Forced Induction Superchargers | Turbochargers | Intercoolers

How much boost?

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Old 12-17-2007, 04:40 AM
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Default How much boost?

10:1 Compression, forged motor, no meth but ATA intercooled, 94 Octane fuel.

What would you consider safe boost level to push through?

10 psi or less

(1 bar would be awsome, if I mixed with race fuel) possible?
Old 12-17-2007, 06:34 AM
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if your forged I dont se why you cant go with a bunch of boost, forged is pretty vague but if you have good parts BOOST IT UP! 1 bar wont be an issue, just watch your afr and your iat without meth in your climate
Old 12-17-2007, 06:45 AM
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I'm building a 9.5:1 347 with compstar rods and mahle pistons (forged) and I'm planning on 10 psi on 91 octane pump and 14.7 psi on 101 octane that can be had about 30 mins away out of a pump at a station. Hopefully not too much timing will have to be pulled in both scenarios and it'll make some good power.
Old 12-17-2007, 09:28 AM
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Just because it is forged doesn't mean that detonation won't become an issue with 94 octane and that high of a CR with a large amount of boost.

(All intercooled >)For 10:1 CR, I wouldn'd go higher than 8#'s. With methanol, maybe 10#'s at the very most. FWIW, 9.5:1 would take 12#'s with methanol, and 9:1 would go 15#'s. I am running 8.8:1 and could do 22#s or so if I wanted to safely.
Old 12-17-2007, 09:53 AM
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It's all in the tune and how conservative you are with the timing and fuel. With 10:1, pulling timing out of it shouldn't hurt low end much, just be careful with a pump gas tune. Theres tons of 10:1 cars on here making good power on 91 octane pump with 10 lbs, they just don't run aggressive timing

Check out this thread...

https://ls1tech.com/forums/forced-induction/783603-high-static-compression-forced-induction.html
Old 12-17-2007, 10:24 AM
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Cam timing will play a big role imo...With higher static comp up the overlap and use the cam timing to lower DCR. That'll help you run higher boost. Meth injection is great as well, the alky control kit is awesome...

1) A2A intercooler focusing on getting the most airflow through the cooler as possible and lowest IATs. (Some even put an electric fan on the back of the intercooler to run in the staging lanes. Also intercooler sprayers work well too)
2) Cam selection
3) Meth injection
4) Great tuning
5) Special attention to the cooling system (dont get the car hot)

10#s should be safe with the above imo...
Old 12-18-2007, 05:51 PM
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my buddys ls2 w/ lq9 heads (around 10:1) sees 13-14 lbs everyday and has no hint of detonation and runs an afr around 9.5-10:1. car has meth injection on it though but uses an ata intercooler.
Old 12-18-2007, 05:53 PM
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btw forgot to mention thats on a 100% stock bottom end. just swapped the heads and ran the gt3 lingenfelter cam.
Old 12-18-2007, 06:48 PM
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My new Motor is going to be up there...... but i by no means am going to try 94 octane with it......
Old 12-18-2007, 11:44 PM
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With any kind of pump gas I'd always recommend Meth inj. with FI. If your tune is safe (very low timing, and between 10.2-11.0AF is what I like on mine) you might be able to squeak by with 94, but I'd keep a close eye on it for detonation, no matter the timing.

Quite a few race-only turbo setups are 10-1 and a little more compression, but on race gas as well of course. I have 8.8-1 compression and when I race I have 116-120oc AND a lot of methanol. (Snow Performance Dual nozzle kit with 75/25 Meth/H20 ratio)
Old 12-19-2007, 05:59 AM
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Thank you all for the feedback, it gives me a pretty good idea.
Thank you Chrispy for cam feedback, it makes sense to me.
Unfortunately Methanol is not allowed here, but I can find some av-gas at a good price.

I think I will start low and add boost a little at a time while monitoring for detonation.

Thanks again



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