What's max boost on pump gas??

Ok, here's my dillema. I've been planning my car for a little while now. When everything was done it would be topped out at 23PSI and would be daily driven at about 15. But then I was thinking, how well would that work on stinking 91 octane gas?? So for those of you who know, what's the max boost you can run on basic 91 gas?? Thanks.

BTW, it's an H22A engine that's being built.

You need to make sure that whatever boost you're running, you have enough fuel for it. So if i am not mistaken, you only need hi octane when raising the compression, not when adding more boost. so 91 should be fine.
Correct me if im wrong.

more boost = more cylinder pressure = more compression

therefore fuel volitility is a factor. dont know what the threshold is for 91 octane is.....

Drift or someone with more FI knowledge, please....

Well it looks like we're just gonna have a few boost setups. One at 10PSI (full pump gas), 15PSI (mix of pump/race), and 23PSI(full race).

The guy building the whole thing said max of 10 on pump gas but I just wanted to get into a discussion about it and see what anyone else had to say about it? I'm gonna be running the AEM EMS so we'll be able to tune whatever we have pretty good.

those numbers sound reasonable....

let us know how your setup goes. does AEM's EMS factor boost curve in?

it all depends on variables you havent yet listed...

static compression, injector size, static fuel pressure, timing advance or retard, ambient air temperature, turbo size and efficiency.. etc.

if you're running enough fuel, with proper ecm adjustment for timing, and a bulletproof bottom end and ignition system, you could boost until the parts fail.

but if the ambient air temperature raises 10 degrees, you can detonate to no end.

Originally posted by drift
it all depends on variables you havent yet listed...

static compression, injector size, static fuel pressure, timing advance or retard, ambient air temperature, turbo size and efficiency.. etc.

if you're running enough fuel, with proper ecm adjustment for timing, and a bulletproof bottom end and ignition system, you could boost until the parts fail.

but if the ambient air temperature raises 10 degrees, you can detonate to no end.


then again, you could also boost 23 psi, retard the timing 20 degrees, flow 1000cc/min fuel injectors with 2 more additional injectors plus jump to 80psi rail pressure, lower your compression to 4:1 static, time your cams for max overlap, and never detonate tho you'll only make 50hp.... but you'll show 23psi on your boost gauge

Well we're planning on using 850CC injectors, 9:1 pistons and I have not a clue about what the cams are gonna be at or the static this or static that. That's why he's building it!! But I do know the turbo alone (at least it is a ball bearing) is costing me almost $2K!!!!!!!! I'm even having somebody reroute my AC and PS so I can fit in a bigger turbo and keep both the AC and PS. I can't wait!!

Originally posted by super 96 accord
Well we're planning on using 850CC injectors, 9:1 pistons and I have not a clue about what the cams are gonna be at or the static this or static that. That's why he's building it!! But I do know the turbo alone (at least it is a ball bearing) is costing me almost $2K!!!!!!!! I'm even having somebody reroute my AC and PS so I can fit in a bigger turbo and keep both the AC and PS. I can't wait!!

Jesus, 2 grand for a turbo for an accord? I paid 2 grand for my ball-bearing T76, but that's for an engine with 2.5 times the displacement!

If you want to get the max potential of a turbo that big, you'll want to run a lot lower compression. 9:1 isn't exactly ideal for boosting, 8:1 or even 7.5:1 would be a LOT better.