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KoreanJoey
11-14-2012, 12:13 AM
Anyone on here have any first hand experience with playing with high compression and low boost with E85?

This is a strictly track car so streetability is not an issue.

I'm looking at 12.5:1 compression, healthy NA cams and lower boost through a T28 on a 3SGTE.

MrWOT
11-14-2012, 01:21 AM
Go bigger. High compression dictates a large a/r. You can run plenty of boost with 12.5:1 and high rpm.

KoreanJoey
11-14-2012, 01:45 AM
Really? See, I'm not really familiar with turbo tech so I'm in the dark right now.

I was thinking 8-10psi on a T28 with the high compression would make for decent mid range spool and a bit of a bump higher up.

Looking at 8500rpm for max HP.

Mafix
11-14-2012, 05:01 PM
i'd assume you want stupid low boost response?
i think you are on the right path but...you'll want a boring n/a cam. a simple set of ge cams should be fine. also i'd look at a bit more modern turbo, though i'll admit i haven't been following garrett turbos.

MrWOT
11-14-2012, 07:23 PM
I would disagree. If you're aiming for peak hp at 8500 then redline is what, 9, 9.5?

A large set of cams and a mid-large frame turbo with an a/r over 1 would be my choice. High rpm + E85 will handle plenty of boost, even at 12.5:1

KoreanJoey
11-14-2012, 08:49 PM
It's the low end response that's the killer.

Yeah, I'll set the rev limit to 9.5. I'm not looking for huge power, I need the response.

MrWOT
11-14-2012, 10:29 PM
BB rotating assembly if you're really concerned about it. But still, I wouldn't touch anything that spins up under 4.5k if you're redlining that high.

KoreanJoey
11-15-2012, 12:13 AM
The high rev limit is more so that I don't have to shift than making power.

MrWOT
11-15-2012, 06:58 PM
Well.. I'm not sure how you wanna work this then. If you run high overlap cams and a smallish hot side, it will revert (exhaust MAP will be far higher than intake MAP) like a mother if you ever spin that high. Normally (gasoline) EGT would skyrocket too, dunno about EGT with E85 though?

Luni
11-15-2012, 11:03 PM
T28 is too small for a 3SGTE at 8500 RPM especially at 12:1 CR IMO.

KoreanJoey
11-16-2012, 12:34 AM
How about a S256? Or a GT30? Would it still provide decent spool up?

MrWOT
11-16-2012, 02:29 AM
First you need to figure out how much power you want to make and where rpmwise you want to make it.

Then use an online flow calculator to get the specs you need, try the one I just posted up earlier http://www.turbodriven.com/performanceturbos/matchbot/index.html

Now you gotta call the manufacturers (Garrett, Borg Warner, Holset) and see what part numbers they can give you for matching turbos. Then call a distributor to find one somewhere.

Mafix
11-16-2012, 11:19 AM
i know exactly what you are trying to do here joey. stupid low response and a turbo that holds to redline. what i didn't think about were the egts at that redline limit on a small frame turbo. in light of that...supercharger?

MrWOT
11-16-2012, 05:54 PM
Trust me on this, if you have cams and are above 5500, response is not going to be an issue with a well setup turbo. There will be some lag, but not a lot, you just gotta learn to drive around it, otherwise you're going to compromise too much on the top end and you're going to regret it for all the power you could be making to redline.

Otherwise just setup the head for lower rpm, no high overlap, no big problem with a smaller hot side.

Mafix
11-17-2012, 12:44 AM
i suppose that would be correct if you kept the rpm above 5K the whole time. but if this is for autocross, that's not entirely possible the whole time (where i race it is nearly impossible). there are other ways to make speed without rpm. you can always increase tire size. or swap the trans (3.91 final in my trans). 10 different ways to do the same thing.

KoreanJoey
11-17-2012, 12:49 AM
i suppose that would be correct if you kept the rpm above 5K the whole time. but if this is for autocross, that's not entirely possible the whole time (where i race it is nearly impossible). there are other ways to make speed without rpm. you can always increase tire size. or swap the trans (3.91 final in my trans). 10 different ways to do the same thing.

Exactly.