Suggestions on built short block and compression ratio?
 

Looking into getting a built short block not to sure on the cr though. I have a maperformance turbo kit with a precision 5858 turbo. I've had a few people tell me to stick to stock cr and a few others tell to go for around 9:1 or around a 10 not to sure what to do any help would be appreciated thanks

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Do like 5:1 and run 80 PSI
JK

How much boost are you going to run and what are you using the car for?

Don't want to run anything in the 20psi area really. I was just running 11.5 on e85 and I'd say around 390,400whp so not looking to run insane boost just to hit those numbers again. And I'd mostly be using it as a street car occasionally drag, but more of a little drift car.

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Go with the 10:1 then as you get more response and off boost power. You should beable to hit your 400whp easy with that, and still have a streetable car.

on e85, my 10:1 ran great with a 5858 and a 6262. ran out of fuel at 525whp on the 5858 with 1000cc's. with the 6262 we upgraded to a walbro 485 and a return fuel system and maxed the 1000's at 590whp. for what you want, id stick around 10:1. a lot more room for error and headroom than 12.5:1 in my opinion. the spool on the 5858 was great for the power it can produce at 10:1

Do you recommend any company's that offer built short blocks? Been taking to full blown and they offer a built short block but their cr is a 9:1 I believe.

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And are you still running that 10:1 cr ? If so what kind of internals?

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i have a full blown motor. they offered 10:1 originally then just offered 9.5:1 as a standard package. they can do any ratio you want, just have to wait until the pistons come in. we did a few 9.5:1 full blown motors and they do really well on pump gas as well as e85. i guess that's why he offers it as the basic "go to" piston now for people who do not know enough about it to choose their own ratio. their built motor works great, just be sure to upgrade the valve springs/retainers during the build

What would you recommend the 9.5:1 or 10:1 how has yours been holding up hp,tq,miles?

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If you plan on truly staying with E85 and not going over 20 psi, I fully recommend you keep the 12.5:1 stock ratio. Only reason to lower comp. is if you're going for the big power (25+ psi) and/or need to get off E85 and run just pumpgas.

sorry but 20 psi is quite a lot of boost E85 or not and there's not a manufacturer out there running CR over 11:1 on a boosted engine
drop the ratio to 10.5:1 and you'll have far more headroom against detonation and not have to swing the cams out to lower the dynamic ratio

look at the rest of the industry and consider that the hundreds of engineers and talent applied to those engines and ask yourself why none of the comtemparies are running high ratio and high boost

Stay with 12.5:1 if you plan on running E85. Detonation isn't really a problem unless you're pushing big boost. All the engine really needs is stronger rods.

While true, OEM's also do not design for all out power. They have other considerations like emissions and long term reliability.

I'd stick with 12.5 as well if your going to run e85. Better response off boost and quicker spool.

dafuq

Talk to your tuner. You're in SoCal, I'd be on the phone to Delicious and whoever they recommend, whether it's MAP, Moto East, Element Tuning or whatever you decide.

Coming on here to figure out what you want and then dropping it off at your tuners shop going 'figure out how to make this work' is complicating the process.

Call Your Tuner!!! They Will Know!!!!!

Yeah heard that from a few people. Won't be on e85 all the time though will be switching between 91 and e85. And I'm still stuck on choosing just want the safest setup with good power and room for better power.

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Yeah already talked to Zach at delicious and he recommended me staying with the 12:5. But kind of hesitant, was running tune by them and over boosted. Didn't know it didn't have over boost protection and the last thing I'd want is to spend even more money. Already have to do a rebuild now don't want to have to deal with it again.

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Manufacturers do not build forged internal engines for the most part.

This thread is about forged internals designed to withstand way more than 20 psi of boost/ 500 whp/ 400 wtq.

All E85 does is give you a huge detonation free window. As long as you don't knock, the forged internals designed to take much more than 500 whp/ 20 psi will be just fine.

Heck, I am running stock unopened motor E85 552 whp for almost two years now.

There's really no need to increase lag and hurt the out of boost performance of the engine going with lower compression as long as you plan on having the knock resistance of E85 when going with the full boost (20 psi) map.

It's fine if you won't be at full power all the time. Get a flex fuel kit and have boost by map setup, or boost by E% content. That way when you go on 91, the ECU can adjust you to a low setting map, say 10 psi lower timing etc... then on E85 killer mode 20 psi, etc...

Best of both worlds, no need to compromise.

Yes already have flexfuel kit to.

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I strongly suggest 6:1 and half a dozen of the other.

Problem with a delicious tune is you apparently don't know what you are getting. More your fault than theirs but sealed tunes are sealed.

Go talk to somebody who does the total package. Including building the engine and tuning.

We have done a couple of FA20 builds this year, including mine. on my personal car i also run the MAP turbo kit (which is fantastic) but i am running a 3076. For my setup we went with a 11:1 compression ratio which worked out great for us

Best regards,
-phil

I've run DT tunes for years set records with them and never had a problem. I would bet my house on you having a failing part, check your wastegate and lines check your mac valve too one piece of dirt in that valve and its game over. Im running 10.5 comp but I'm boosting over 30 psi too. 12.5 for 500hp or less will be fine. Or 12.5 for 20psi or less with E85 with 91 I wouldn't boost past 10psi personally.
I truly feel its not the tune, they don't just work one day and change the next, it has to be mechanical. Also do what I do and get a stand alone boost controller /protector that lets you control the boost and everything about it. I run a AMS 2000 Pro and love it!!!!!!!!!
Call Jeremy at Outfront Motorsports in Buena Park tell him I sent ya and to give you that big brother hook up on a motor and then cal Ian at MAP and tell him hook you up on a boost controller turbo smart isn't that expensive and work good. Mark at Spencer Fab runs one and likes it I believe Outfront stocks them too.

I've never had an issue with my ecutek setup. Closed loop boost control and boost cut, standard Mac valve with push loc hoses/fittings. I melted the rubber wastegate line back when I had my avo kit and the ecutek boost cut worked flawlessly

What about for a built motor running a supercharger, what compression ratio would be good? I was looking at 10:1 compression.