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dicko

Help me improve the powerband of my SR20DET race motor?

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assad i guess it boils to this: Keeping his well built race motor isn't worth it compared to a stock motor. His current motor will not deliver a wide, linear power band when coupled with a standard turbo (as per the rally regulations); this is a problem. He is therefor faced with, roughly, two options: Make the current motor more suitable (cams and other alterations) or swap out for a standard motor. Seeing as many people here on NS have had experience dealing with motors that don't quite work out as planned, the general consensus is that the stock motor option is better even if the race motor wasn't worth more. Considering the race motor is certainly worth a whole lot more than a stock motor, the stock option would free up money to spend on more important things, like having a great time rallying.

 

Your argument, from the few posts I've been able to decipher, is that it's cheaper/better/whatever to keep a 'bulletproof' built motor and rebuild it again to new specs... Good luck getting a quality rebuild for less than the price of a stock SR. Part of your indication there was that since he'd need to re-buy many expensive parts for a new SR but this wasn't part of the recommendation; you'd use the stock SR with stock internals. There's just no need to open it up. You can get 200kw from an SR delivered reliably in a rally setting.

 

It's not all about having the best parts or the most 'bulletproof' setup. It's about having the right tool for the right job. If the OP was racing on tarmac and was allowed to use non-standard turbos then nobody would be advising him to get a stocker, because what he has would be the right tool for that job.

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Well said Matt, but I think assad is just trolling. I listed the parts that would have to be purchased to lower the compression ratio in a previous post, but he paid no attention to it.

 

Assad, what I don't think you've recognised is that between lowering the CR of the OP's current engine properly (i.e not slapping in the worlds thickest head gasket) and straight-swapping his current engine for the bargin price of a stock SR + $500, there's at least a $2000 price disparity. Unless the current engine has head/main studs (lowers the cost a little), then there's a minimum of $1000 of parts and $500 of his time (assuming his pay rate is rather low, otherwise it's a lot more), making the difference between the two options around 2 grand. I rebuilt my SR20 a few years ago so my pricing should be accurate.

 

Considering a 200kw, 8.5 - 9:1 CR SR20DET really isn't going to have detonation issues warranting pistons/rods with a highly ductile material (i.e. forged pistons and rods), the only advantage of rebuilding his current engine is the peace of mind from having new bearings, gaskets, rings and the correct bolt torque values. He could gain a lot of confidence in a used stock SR20 simply by bolting a bellhousing to the engine (whilst it's outside the car), attaching a starter motor and running a compression test.

 

If he were paranoid, then removing the oil pan/sump, removing the mains bolts/girdle/caps, unhooking the timing chain from the sprocket and inspecting the crank and bearings would be an option too. If he felt the need he could then install new oem Nissan bearings based on the crank/block stamps (you can maneuver the crank if you remove pulley, oil pump insert and timing chain sprocket), otherwise just install the girdle and caps, torque to spec using TTY main bolts and call it a day. Personally, I'd just run a compression test and see how it goes.

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lol, new pistons 500, new bearings 150, camshafts 600 then gaskets & seals! How is that more expensive than buying a used sr and swapping it? I would wayy rather a freshly built engine than a thrashed one with unknown history! If he is participating in rally events he should have the resources to take care of a quick rebuild! IDK bout you guys but if you cant afford a quick rebuild when you are asking what should i do to change my setup to better suit my needs and why are you entering rally events?

 

You guys are either soooo broke you blame people that can afford to change setups on your miserable lives or you guys have no freinds no life and you try to stick your penises in your exhaust pipes when your cars warmed up because thats the closest you can get to the real thing!

 

Johnie please stop acting like i need you! There are 500 tuners in syd that have better resources, reputations and experience! I would rather pay mrt or croyden for their time than give you a cent LOL you crack me up so hard..

 

pmod putting a thicker hg is NOT a sufficient way of working around cr numbers and is not a good idea at all, there are many other ways to bring cr down without changing pistons, but over 11:1 is too high to work with if it was around 9.5 or 10 CR could be brought down closer to 9 using methods other than using thicker HG or changing pistons! but since i know nothing i guess i wont say how :(

 

You guys are the ones who first cried about his CR, OP shouldnt of put stage 3 cams in that engine to begin with! and yes those cams didnt come with the engine did they dicko? sorry but you should of at least done 2min of research before you brought stage 3 cams, bigger is not better..

 

And if OP knew he was going to be aiming for midrange from the beggining he should not of brought the engine he has! he should of brought a stock engine TO BEGIN WITH!

 

That is the reality and taking out your anger on me is not going to change dickos poor decisions! If i was dicko i would fix those poor decisions myself by spending 1500 bucks and "wasting" a weekend (rebuilding engines is not time wasted), THEN he would have nice power curve with fresh engine ready for his events with minimal time wasted! Selling his current engine then buying a new one would take SOOOOO much longer!

 

I am not wrong, you people can just not agree with me out of PURE jelousy! Its not my fault youve wasted your lives doing nothing! dont blame me! LOL LOLOLOLOLOLOLOLOLOLOLOLOLOLOLL AAAHAHAHAHAHAHAHAHAHAHAHAHHAHA

 

I can seriously not beleive how much NS has changed over the last 3 years! 3 years ago no one had a but plug stuck up their that they couldnt fish out!

 

I am sorry for being rude but everyone thinks im a wanker and its ok for you guys to dish it out but when i say something i am the worst dumb retard nil wisdom child that knows absolutely nothing!

 

Oh and pmod why would you follow OEM specs? Col said ALL mechanics do not build engines to oem specs? EVERYONE should delete or burn their workshop manuals and just guess! Because all mechanics say " NOT TO OEM SPECS"

 

Seriously i would have loved for this thread to go a different route, but it has not entirely been my fault! To begin with Varvs shouldnt have said " i know nothing about building engines but you are wrong" LOL nuff said

 

Damn guess that 4 year apprenticeship done no good :( shoulda chose plumbing or something :(

 

I cant even beleive im still here typing, its funny hehe

 

edit: couldnt help it! Im the dumbass that knows nothing! But dicko bought 272 camshafts to suit a t25 when he was going for midrange!!!! OH but i know nothing!? even the noobest of noobs know high lift + high duration = TOP END POWER which sacrifices low end!!! if you dont know this you should not be working with cars, But I should go educate myself? i never said i work with dynos or tune cars did i? but since ramp rates are soooo important EVERYONE who works on cars HAS to know what they are and how the effect dyno rollers and if you dont know what they are you are soooooo dumb you absolutely know nothing at all you retard ohhh sooo dumb go educate yourself, there are alot of things i know everything about that you know barely anything about aswel so dont act like your the best person ever in the world that will crush me with your pinky and thumb on your left hand! LOL

 

 

Its ok for you guys to judge and call people dumb, lets go for a meet 2moz night yea? everyone who is from syd in this thread lets meet! Id love to conversate with you guys, then we will really see who is soo dumb the have nil wisdom..

Edited by assad11
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http://skepdic.com/sunkcost.html

 

"When one makes a hopeless investment, one sometimes reasons: I can’t stop now, otherwise what I’ve invested so far will be lost. This is true, of course, but irrelevant to whether one should continue to invest in the project. Everything one has invested is lost regardless. If there is no hope for success in the future from the investment, then the fact that one has already lost a bundle should lead one to the conclusion that the rational thing to do is to withdraw from the project."

 

 

assad11 in a nutshell:

'To continue to invest in a hopeless project is irrational. Such behavior may be a pathetic attempt to delay having to face the consequences of one's poor judgment. The irrationality is a way to save face, to appear to be knowledgeable, when in fact one is acting like an idiot.'

Edited by Varvs

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Assad you say he shouldn't of got the car with that engine however dicko probably got for more reasons then just the engine. The might be a lot of other goodies on the car he hasn't mentioned because it wasn't relevant to the op. You have chosen to comment your opinions and make fun of all others, some of these guys will have more experience than you just because you have done an apprenticeship doesn't mean you are a good mechanic, by the way you are talking and acting you sound like a rather arrogant and shit one. You may call us posers but a lot of has have had a lot to do with cars. Although not relevant to the op my poser s14 can be seen here

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I'd say you've confirmed that you're just trolling Assad, based on your comments trying to school me regarding lowering compression.

 

Mate, we all know you can lower compression by cutting the head bowl, installing [custom] shorter rods, installing a thicker headgasket or changing pistons, but the ONLY things that makes sense for the OP to do is to change the headgasket or pistons. Since the headgasket is a terrible idea as I clearly stated, that just leaves the pistons.

 

"I am sorry for being rude but everyone thinks im a wanker and its ok for you guys to dish it out but when i say something i am the worst dumb retard nil wisdom child that knows absolutely nothing!"

 

You changed your advice 3 times to match rebuttals, then started talking shit and insulting people. If you weren't rude and arrogant in your replies, people wouldn't think you're a wanker. I thought you were a troll from the first rage-post, so I remained polite because it really doesn't bother me, and I'd rather Dicko get good advice. If you're just trying to get a rise out of people, you definitely succeeded with some, albeit not with me.

 

"That is the reality and taking out your anger on me is not going to change dickos poor decisions!"

 

Dicko came here for advice, and received good advice from an ex-professional mechanic that has built and raced plenty of cars, a turbo manufacturer that actively tests turbos for SR20s, a guy that has bought and sold more SR20s and parts than anyone I know, and a bunch guys like me that have fully-rebuilt SR20s themselves, been there, done that, know the costs and pitfalls. Nobody has taken their anger out on you. People initially corrected your advice since it was originally poor, then you changed your advice to be "rebuild bro", which although an option is not the most sensible path for Dicko to follow, and from there people were merely responding to your insults and taunts.

 

"Oh and pmod why would you follow OEM specs? Col said ALL mechanics do not build engines to oem specs? EVERYONE should delete or burn their workshop manuals and just guess! Because all mechanics say " NOT TO OEM SPECS""

 

For the simple reason that if you're using oem Torque To Yield bolts, you have to use oem specs. TTY bolts stretch... you can't just pick any figure you like and expect it to work. When using head/main studs you use a different set of torque values to oem because they don't stretch, and when using an non-oem headgasket the torque values change yet again. You can install any parts you like, but the torque figures must match the parts, crush of the material and be suitable for alloy thread (to avoid stripping it). For the piston rings, you have to grind to achieve an end-gap suitable for the application and piston material, or you'll have binding issues or a tonne of blowby.

 

"Seriously i would have loved for this thread to go a different route, but it has not entirely been my fault! To begin with Varvs shouldnt have said " i know nothing about building engines but you are wrong" LOL nuff said"

 

Your replies are your own doing, and trying to shift blame for your attitude onto Varvs is absurd. What Varvs said wasn't an issue at all, since the OP's problem was fairly clear to anyone with an understanding of detonation and the issues high compression with forced induction present, neither of which require you to have experience swinging a spanner to recognise. It's in the same way that one can understand the science behind small-scale rocketry without ever having machined thier own tube, designed fins, made a launch pad, built a furnace and created their own black powder charges.

 

"Its ok for you guys to judge and call people dumb, lets go for a meet 2moz night yea? everyone who is from syd in this thread lets meet! Id love to conversate with you guys, then we will really see who is soo dumb the have nil wisdom.."

 

I was planning on going to the gym Friday night, but I'm happy to attend a meet if someone organises one in a good location and the numbers are there. If however you're trying to start a fight or something, I have better things to do... like go to the gym.

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and you try to stick your penises in your exhaust pipes

 

Wait, noone else does this? I thought this was how do you do "car culture"

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Perhaps we are going about this the wrong way.... Assad, if you had to build a rally car that had to comply with engine & platform limitations and standard turbo limitations.... money aside.....

 

AND

 

you were building a S13, what would you do?

 

p.s. Dicko, a baffled sump and potentially the GTiR oil lifter could be beneficial to your build

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If we can, can we direct this back to topic and a couple of technical questions which haven't been closed off - as my first post, my understanding the 'why' for me is as important as the advice so I can better understand the relationships between cams/ boost/ compression/ turbos and manifolds.

 

Main things I'm not clear on:

@as Niknuk was saying, a motor flowing 200kw should be flowing the same air, whether that's achieved by boost or static compression. I understand that the turbine and internal wastegate will struggle, but it has an external wastegate (tail 38mm I think). The situation we are looking at here is that boost will bleed off through the external wastegate probably from 5000rpm. In it's current tune it has 185rwkw (5500-7000) (Unigroup dyno) on 10psi (170rwkw at 5000). More boost wasn't applied at the last tune because the spark was blowing out (incorrect plug gap). There is no reason to suspect the turbo couldn't flow 16psi (previous owner had it running that and maybe a touch more - and I think that tune ran very rich to keep exhaust manifold temps down). At 16psi and on rule of thumb 2kw? per psi we are close enough to 200. With a tighter tune this setup is already at desired power, it's just about moving that powerband down the rev range. So with revised tune we could be hitting near enough to 200rwkw from 5000rpm, beyond that boost would be bled off by the electronic boost controller and external wastegate (I assume) and so bypassing the flow limitations of the turbine. If I have this wrong, could someone give a technical explaination - as I haven't grasped this properly from the otherwise good advice posts so far? (Thanks everyone for te posts so far and helping me with this!)

 

@where is torque in all of this? I only have a limited understanding of relationship between torque and power, but good low down torque is also on the want list for rally. The higher static compression, in my mind, would be helping torque in the 2500-4000 rpm range and the combo of static compression and whatever boost the turbo can spool up by then should be combining to give more torque than comparing to say 9.5:1 and the T28? Or have I missed the relationship/ importance of cams in this?

 

@the use of a hydraulic profile cam, in a solid lifter head. We all know not to do it the other way around, but is there any experience this way round? (Other than it would be a waste of money setting it up to then use a hydraulic cam, and need more maintenance)

 

I'm listening carefully to the fix the motor vs buy a new stocker discussion. As this is competitive Motorsport with significant commitments of time and money just to turn up on the start line, bolting in secondhand motors that are untested and unproven is generally not a good way to get the best value out of Motorsport overall if you've bought a dud and it pops. The amount of testing that can be done outside of competition is very limited - it's not like you can drive around as a daily for a few weeks prior to a race and work out if anything in the second hand motor needs attention. So factoring in the turnover cost also would need to consider at least a half pull down and check, as a minimum (good to see some costs on this in posts above- thank you).

 

Thanks again to everyone who has contributed - if we can get some more clarity around the tech questions above that would be awesome! Thank you!

 

Edited by dicko

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@ #2 - engine power is torque multiplied by RPM. If you're using SI units it's literally power = torque * engine speed.

 

So if you make 200Nm from 2000rpm to 4000rpm, you will be making exactly twice the power at 4000rpm as you do at 2000rpm. And so on.

 

You'll notice from before/after dyno sheets that bigger camshafts basically make more power by moving torque curve over to the right /higher rpm

Edited by Skepticism

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Close,

 

 

HP = Torque x RPM ÷ 5252

 

Taken from here:

http://www.epi-eng.com/piston_engine_technology/power_and_torque.htm

 

 

 

 

I think this is being over complicated. Just stick with what you have, go back get a retune and see what it does. It'll either make 200kw or it won't.... At worst you've lost a couple hundred for a retune but learnt something about your setup.

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^ he should really swap cams before his tune tho 272s will GREATLY hinder mid range and he wouldnt be happy until 5k+rpm

 

why was wizard saying OP has a forged crank? No one said anything about a forged crank lol of course the standard sr crankshaft is forged! OP has a BILLET crank!

 

No i never even thought about anything to do with fighting! we are not in year 7, i also have better things to do and would rather learn from a conversation than lose brain cells in a fight.. And of course torque specs must be followed on things like cam caps, rod caps, head studs/bolts etc, i was just saying to the guy that wasnt too confident in his work that if you have followed the specs and done things the right was as the manufacturer recommends then he should be confident in his work! I never said live & die by oem specs all must be exact! lol every builder has their own methods and thoughts on what works better than others and for a mechanic (Col) to assume different is quite funny!

 

Lol ok ok il stop now it was fun while it lasted tho! hehe.

 

anyways, the motor might flow the same amount of air reguardless of CR but the way it uses that air is what differs, just because the higher CR you run will make it easier to make the same power at lower boost levels doesnt mean you should just go for the highest CR you can possibly get, just like everything there is a sweet spot that should be aimed for depending on your application and goals, My uncle was a great engine builder (jap engines in specific) for 30 years and he also has the idea that you should run a higher CR because its easier to make power but he never ran anything over 10:1! I never really asked why he doesnt go a higher CR but i asked if he ever ran into knocking problems or other issues and he said nope never as long as we used 98ron it was never an issue. (unless you start pushing harder than it should be pushed then of course you can have issues reguardless of cr)

 

Wish i could tell you alot more dicko but i have always aimed for just above the standard 8.5:1, seeing an sr with a ratio as high as yours is fairly uncommon, most n/a cars have lower compression ratios than yours lol hopefully someone else can give you more info on why running such a high CR is not the best idea?

 

As for moving the power curve down, you can play with your timing events to adjust the power curve to earlier on or later, the tuner should take care of this when you let him know your needs, generally advancing the timing events will bring the curve down in the rev range, overlap & lobe seperation angle can also play a part in how the power curve sits, you should have a quick read up on these so you get the general idea if you dont already.

 

If you have the standard sr20 intake manifold with the long runners or can find a cheap one i would throw it back on, i already spoke about that and i think it was worth mentioning again. The baffled sump is also an excellent idea especially in your case! chinese ones can be had for 120 bucks or so! maybe even cheaper! and they are fine just use a quality liquid gasket like you usualy would and youl be sweet.

 

I heard that using hyd cams on solid lifters can be noisy, I have no experience with mixing these parts, personally id just stick to hyd but different people prefer different things..

 

Hope i wasnt too rude this time lol pmod your cool!

Edited by assad11

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Hope i wasnt too rude this time lol pmod your cool!

 

Cheers.

 

Yeah, this post was alright. I prefer to be chill with my replies if possible.

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260 procams 12mm lift.

Come in hydraulic or solid.

I think a better idea than poncams for Dickos car.

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260 procams 12mm lift.

Come in hydraulic or solid.

I think a better idea than poncams for Dickos car.

 

Because of the duration and lift are better or at least similar, or because I don't have to convert to hydraulic head to run them? Both?

 

Also it's been my engine builder and my decision the set the rev cut to 7000 because we didn't think sr's were reliable beyond that in terms of valve train. This particular motor and iterations thereof has had 3 previous terminal valve train failures for the previous owner. These were blamed on holding the car on the limiter for extended periods, and also when we rebuilt it we noticed some evidence of valve touching pistons, which we have corrected by flycutting pistons.

 

I'm forming the view that the rev limit can probably be increased with a solid head and either 256's or 260's, which might also extend the powerband at the top end. This might be something like a 7500 cut which will allow revs safely to 7300 without having the limiter kick in. Again not looking to chase higher power at this rev range, and I expect the wastegate would be bleeding off boost to maintain power at around 200rwkw. Interested in feedback on that?

Edited by dicko

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wastegate's going to be bleeding off boost the moment you hit whatever you've set your boost at :P

 

Stock turbo is typically at it's limit around that power level... better watch your intake air temps.

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Johnie, it was like 214 or 216 at peak not exactly 200 on the dot, and to give you an idea, i raced that exact tune on an unrestricted hyosung gt650r in a 60-200+ run, from 60-180 the hyo was just sitting infront by half a car, after 200 the hyo started dying off (v twin) and tops out at 222/223, the 180sx passed easily about 205 and continued to pull until he backed off.

 

I am in no way saying this is the fastest sr of all time and everyone must bow down! I am referring to an sr that REALLY makes a genuine 210 or 220 whatever it was rwkw, if JEM are such bad tuners why is their garage CONSTANTLY packed with well known drift, drag and street cars?

 

Hyosungs are shit we all know that, but for a learner legal bike that you can un-restrict at home without anyone knowing it has been unrestricted leaves you with the fastest bike you could possibly ride on your L's. Id rather stick with road trails for your L's tho.

 

I have ran alot of different cars on the hyo's and not many at all can even come close to keeping up like the 180 did! This is true story no trolling no exaggerating, i know from personal experience how that car performs and it is fine the way it is/was, if it was mine id want a bit more, but he likes it that way and swears by stock internals so if he is happy let him be lol the car also only has 99,xxx amount of k's on it too! It was a nice example of a 180sx until the painted it white and threw a BN kit on it :( (used to have vertex kit and red in colour, interior gutted with 6 point roll cage)

 

Anyways there is also a 260* with 11.5mm lift! this would suit dicko even better! Shift performance has one in stock for the vct engine and they are also on ebay with that combination, i would throw them on if i chose to tune with the disco still on, but i highly doubt itl be staying.

 

Also dicko i would look into what type of rev limiter you are using or what your ecu is programmed to use, alot of guys have had trouble with rev limiters! Ending up in broken valve trains! (mainly rocker arms that ive heard of) some guys swear by fuel cut some swear by ignition cut! this muddies the water even more but it seems that engines vary in what that paticular one prefers! Probably depending on power levels and supporting mods?

 

Maybe johnnie the king of tuners can elaborate?

Edited by assad11

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this is what i found in an old thread, bee-r is ignition cut and seems to not match well with the sr engine coming from alot of people that have had trouble with ignition cuts!

 

"had a bee'r on my car for about 3 months and i'll never put one back on. if you are hitting limiter a couple times a day or even a couple time an hour like myself then you will have heaps of problems. i was fouling plugs so quickly to a point where the car wouldnt start, had to roll start down a hill. not to mention i blew my turbo flange gaskets and my dump gaskets. also destroyed my $500 cat converter. it was great fun though. upsides do not out weigh the downsides in this case. fuel contaminated oil, glazed bores, wickid blow bye and broken ring lands is what you can expect. have personally seen melted rb20 pistons from abuse of a bee'r.

 

some food for thought

 

sab "

 

I really dont think dicko will be on the limiter as much as drifters would be lol but still should be looked into, ive heard of people mis-shifting and breaking rockers from over revving, and not 1 or 2 people! And usually the people it happens to seems to happen a few times not only once. (maybe before they notice its the limiter causing the issue?)

Edited by assad11

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I dont think anyone mentioned bee*r. Rev cut can be changed within the ecu? Its all about the values.

 

Johnny has helped me out before because he's a decent person and that's probably why he has friends.

 

~200 rwkw is what you would expect from a stock s15 t28. I don't think anyone could justify that $ investment for that power increase but you're welcome to try.

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the bee-r was an example of ignition cut! And the previous owner broke valve train 3 or so times! Which could be a result of rev limiter selection! OMG thats why i mentioned it, if it is the cause of previous owners problems it would be well worth looking into what rev limiter he is running on current ecu!

 

Some ecus have fuel cut some have ign cut some have both some have other ways to limit revs, it depends on what you are running, if dicko is running ign cut and his ecu has a choice, he should research and ask around to find out what would be the best thing to suit his app, alot of people swear by fuel cut alot of people swear not to use fuel cut and vice versa, this is why i brought up the bee-r! Not because it was previously mentioned! I cant remember saying someone said something about a bee-r!

 

Some people on here are just soooo brain dead! THINK! you have a brain so use it!

Edited by assad11

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http://www.plmsdevel...rs/gf_s15.shtml

 

stock s15 dynod at 143kw, derrrr

 

after they tuned it and done a few things they were able to crack 200..

 

STOCK S15= under 150kw

http://nissansilvia....ttach_id=250958

 

142kw before tune 170 after tune= derrrr

 

 

http://nissansilvia....howtopic=411815

 

from link above- "180 with the old T28BB: Mods include T28BB, GKTECH FMIC, CES 3" TB Exhaust, CAI, Walbro FP, E-Boost II on 10psi, RAS Kit, Koyo Radiator, Nismo Thermostat" = 170kw

 

or are all these poeple lying??

 

oh but i am wrong sorry i bow down

 

And s15s should have better top end not better response than non vct, when vct is engaged (from 1050-5700rpm timing events are the same as the non vct, its only when disengaged that intake retards 20* which would help top end power.

 

I am not being a dik, i am just forwarding information that is correct! a stock standard untouched s15 will not come close to 200kw and if you think it will you are dreaming lol just google stock s15 dyno and there are tons of dyno sheets that support this claim!

Edited by assad11

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Close,

 

 

HP = Torque x RPM ÷ 5252

 

Taken from here:

http://www.epi-eng.c..._and_torque.htm

 

 

Nah.. I said SI units.. not HP / ft-lbs.... not hugely important though. 1/5252 is just a conversion factor due to using non-SI units.

 

Power (Watts) = Torque (Newton metres) * Speed (radians per second)

Edited by Skepticism

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260 procams 12mm lift.

Come in hydraulic or solid.

I think a better idea than poncams for Dickos car.

 

Because of the duration and lift are better or at least similar, or because I don't have to convert to hydraulic head to run them? Both?

 

Also it's been my engine builder and my decision the set the rev cut to 7000 because we didn't think sr's were reliable beyond that in terms of valve train. This particular motor and iterations thereof has had 3 previous terminal valve train failures for the previous owner. These were blamed on holding the car on the limiter for extended periods, and also when we rebuilt it we noticed some evidence of valve touching pistons, which we have corrected by flycutting pistons.

 

I'm forming the view that the rev limit can probably be increased with a solid head and either 256's or 260's, which might also extend the powerband at the top end. This might be something like a 7500 cut which will allow revs safely to 7300 without having the limiter kick in. Again not looking to chase higher power at this rev range, and I expect the wastegate would be bleeding off boost to maintain power at around 200rwkw. Interested in feedback on that?

 

It gives you the option of going hydraulic or solid. They aren't massive duration like the 272's but have more mid and top end which is where you want it for your application.

I've got a set in my stock sr20 with rocker stoppers and a cheapo td05h-18g turbo making approx 230rwkw. It gets driven to the track, raced and driven home. As you know the rockers are the weak point and like to come off / break at high rpms. So far (touch wood) I haven't had a rocker failure yet.

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never said I was king of tuners, never said JEM were shit... but for a GT3076 to be make sub 220kW there's either something wrong with the car OR something going on with that tune..

 

And.. in regards to rev limiters.. most modern aftermarket ECUs support a soft & hard cut which prevents the aggressive cut thus preventing smashed rocker arms... an example, you do a soft cut at 7500 to cut cylinders 1 and 4, then set the hard cut to 7700 to cut all... also you can set a "cut time" as well so the power doesn't instantly come back on and smash shit to bits.

 

I personally like to cut both fuel & ignition for rev limiters, this ensures you've got no residue fuel to ignite (to create a lean condition) and you've got no spark to ignite the fuel.

 

 

Here's a T28 SR20 tuned by Unigroup making 206kW:

http://nissansilvia.com/forums/index.php?showtopic=494880&view=findpost&p=2088614755

 

190kW:

http://nissansilvia.com/forums/index.php?showtopic=192957&view=findpost&p=6423255

 

175kW

http://nissansilvia.com/forums/index.php?showtopic=192957&st=330&p=6406564entry6406564

 

194kW:

http://nissansilvia.com/forums/index.php?showtopic=192957&view=findpost&p=6024906

 

 

I think you're neglecting the fact that that PLMS article is quite old and at the time most tuners didn't push the boundaries of SR20 tunes... Pete from PLMS has tuned several SR20s with T28s and they've all made close too 200kW with just a T28. If you have a read on the nistune forum you'll see he openly shares his experiences.

 

Oh yeah, here's the creator of Nistune's S14 with a T28 Bush Bearing turbo making 212kW then 220kW on E85 (2nd last post, 1st post is his R34).

http://forum.nistune.com/viewtopic.php?f=10&t=3060

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Maybe there's a screw loose somewhere?

  • Upvote 1

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cuz look at what this guy has done to his s15 to hit 190kw!

 

Size of engine: SR20DET

Modifications to the car:

-Greddy FMIC

-HKS Front Pipe

-HKS Silent Cat Back

-Decat Pipe

-Apexi Pod Fitler

-Power FC L-Detro

-Manual boost 'T'.

-Wallbro intank fuel pump.

Type of turbo: AMD Bush Bearing T28

When does vehicle begin boost: tba

When does vehicle reach full boost and what PSI: tba

Does the vehicle have Cams? if so; HKS Stage 1 264/264

Max power achieve at what boost: 255rwhp @ 16psi

 

Ovaboost Dyno 255rwhp @16psi

 

And:Modifications to the car: Stock bottem end, Poncams, BC Valve Springs, Tomei 740cc injectors, tomei rocker arm stoppers, cobalt rocker arms, Tomei expreme dump pipe + 3 inch front and apexi cat back,highflow cat, walbro pump, z32 AFM, nistune tuned by ECC, metal intake pipe, Greddy Profec B Spec 2, unboxed pod filter, Blitz DD BOV, FMIC.

Type of turbo: Tomei ARMS M7960

Boost:Low boost 14psi, High boost 18psi

When does vehicle begin boost: 2500

When does vehicle reach full boost and what PSI: 3700rpm - 3900rpm

Max power achieve at what boost: 206.8 kwatw on 14psi

221.7 kwatw on 18psi

 

But since stock s15s have 200kw this guy above is retarded and something must be loose on his car....

 

227.8 kwatw on 19.5psi

Fully built one:

Full NITTO build SR20. Low mount 3071r t28 flange. New 1200cc highflowed injectors. Drift suspension etc. Tomei solid top end.

22.9psi 307.7kw max run. 306.6kw on a higher load.

dont forget drift suspension added 40kw, so that really evens it out to what i was saying before!

Edited by assad11

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