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Hey guys

 

Have been reading around some sr20 builds, and have seen a few people running fairly high static compression with good power results and still responsive. just wondering if anyone on here is running a highcomp turbo setup?

 

i know you need to run E85 and will need a good tuner to get it right, but are there any downfalls from a set up like this? (ie drastically reducing engine life, really high running temps etc?) am aiming for around the 300kw mark on a forged blacktop sr20 with brian crower 264 degree cams and a gtx3071 twin scroll set up, but still want it to be as responsive as possible which is the main reason i'm looking at running a higher compression.

 

what do you guys reckon?

 

 

cheers guys

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High comp is an excellent way to get good response. I'd run 9.3-9.5:1 for 98 RON or around 10.2-10.4:1 for E85.

 

I'm running 9.5:1 on 98 RON but I'd like to switch to a 25% ethanol mix when I can be bothered so I can get more ignition advance into it. Mine's sleeved and bored to 89.5mm to get 2.16L. It makes full boost at 3300rpm with a BorgWarner EFR 7064 .92. I'd still like to make a couple of tweaks before posting dyno sheets etc.

 

I can't recommend a BorgWarner EFR enough. I can't get over how responsive my turbo is for it's size. One of the smaller ones with the upcoming 0.80 divided housing should be incredibly responsive. I hope they offer the new 0.80 divided housing for the 7064. I'll swap it over as soon as I can get my hands on one.

Edited by bradsm87

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Stock SR20DE. GTiR T28 with up to 13.5 PSI boost. GTiR quads modified to fit DE. Air to water intercooler. 550cc injectors. Poncams.

 

Just shy of 300 fwhp, with over 360,000 klms on the odometer.

 

Why not do it??

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^^ because thats only like 210KW

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E85 burns slower and cooler, who told you it burns hotter? who told you it reduces engine life?

 

All E85 does is clog up your injectors :)

 

Because it burns slower & cooler, you're able to dial in shit loads more timing into the motor, this creating more power. Also E85 is less prone to knock than 98, which actually prolongs your engine life. So back to your post, it's actually easier to tune E85 than 98, and the chances of blowing your motor on E85 is less than 98. E85 will just misfire or splutter when you dial in the wrong timing, 98 will knock and blow apart ringlands.

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Currently building my SR20 for higher compression. Manley rods, 9.1:1 CR Wiseco pistons and a light head and block deck with an oem headgasket, which will raise the compression a little further. Recently got handed some NA cams by one of the guys, so I'll see how those go.

 

Not shooting for mass power, but rather as much torque as low in the RPM band as I can get it, without experiencing a plateau in power before hitting redline. Was previously giving serious thought to a twincharge setup with a small and cheap roots or twinscrew supercharger like an SC14, but I'll see how this goes first. However anyone who had driven a twincharged car knows that twincharge is where it's at.

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E85 burns slower and cooler, who told you it burns hotter? who told you it reduces engine life?

 

All E85 does is clog up your injectors :)

 

Because it burns slower & cooler, you're able to dial in shit loads more timing into the motor, this creating more power. Also E85 is less prone to knock than 98, which actually prolongs your engine life. So back to your post, it's actually easier to tune E85 than 98, and the chances of blowing your motor on E85 is less than 98. E85 will just misfire or splutter when you dial in the wrong timing, 98 will knock and blow apart ringlands.

 

He wasn't refering to e85 as being the downfall of the engine, he was refering to running high compression.

 

I'd would prefer to think anything under 10 isn't high compression, if stock engine is 8.5 and you raise it to 9-9.5 that's not high is just higher than stock.

 

Google search will give up a lot of answer in regards to building any type of high comp turbo engine.

 

High comp will produce good torque and awesome response but make your engine into a time bomb in the wrong hands.

 

From what I've found through researching the reason for going low comp is to provide a safe engine that's not on it's exteme limits.

We're as high comp motors are border lining every aspect of the motor and one slight miscalculation and she is gone.

 

Need a real good tuner who knows what he is doing.

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maybe I didn't read properly haha..

 

+ back then we didn't have consistent fuel, running lower comp reduces changes of knock on rubbish fuel, these days E85 is like bawse fuel and even 98 is quite consistent, not to mention newer ECUs have a knock map, i.e. retards timing on knock reducing chances of motors going kapow..

 

So please don't buy a dinosaur PowerFC, they're great for that they "were" but these days for similar money you get so much more such as MAP sensor, launch control, e-flex, closed loop wideband for auto tuning a/f off load.

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thanks for everyone for your input, i was thinking of going for around the 10 or 11:1 comp mark. yea have heard e85 can be a bit of a dirty fuel, not as refined as 98, will be running 3 filters before the fuel gets to the rail. yea have heard that you can dial in a ridiculous amount of timing on e85 and it still doesn't knock. still havent decided on a tuner yet, but uni group is on the cards, have heard there very good and they work on heaps of high end build(ferrari and porsche targra car's). would love a twin charge set up, but reckon its a bit complicated for the response gain.

 

As for the ecu, im tossing up between link and haltech, will need something that can run a flex fuel sensor as e85 strength changes from season to season.

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another question for you guys, would the standard block stand up alright with 11:1 comp and about 20psi? would sleeving it be a good idea for reliability sake? and would the head need looking at considering its going to be under much more pressure with the higher compression?

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10.5 will be a decent figure.. run the E85.. give your tank and fuel system a good clean as all the sht in the tank the E85 will dissolve and pump it into your fuel system.. as been said you can add more timing.. most of the fun is feeling the difference in response as you can add it in the transition too..

 

there are a few datos running smallish turbo's with the E85.. helps them with more boost and also add's to already lightning response.. watch out cranking your static compression too much as you may find there will be a point where you physically cant screw in boost without getting knock.. and sometimes that can be 15PSI.. if you are going too far... also cam choice and cam setup will come into play.. Donny has a fair bit of knowledge in this area..

Edited by chris2712au

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