I was wondering what would be the limitations of pumped gas ( 93 octane ) in a turbocharged B-series? I mean, how much horsepower can it handle in a safe margin and maximum timing? Lets just say a fully built B-series motor with an average size turbo that can easily push out 500+. I know theres a few knowledgeable tuners in here and i wanted to see their opinions on this topic, well lets hear them

 

I would like to know as well....except 92, cause that is as high as I can get here...

-Ryan

 

im not a pro but i personnly run 1 bar on pump gas daily and have seen 414whp on 93 octane in the past!

 

You guys should be happy, in we have 91 octane here. Our low octane gas cost as much as your high octance gas.

 

i asked the same question to Howard (AR Fab) and he said 18psi for my setup, and after that you need race gas.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Teg4e &raquo;</TD></TR><TR><TD CLASS="quote">i asked the same question to Howard (AR Fab) and he said 18psi for my setup, and after that you need race gas.</TD></TR></TABLE>

How much compression are you running?

 

is it by psi or whp you be limited?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boosted92 &raquo;</TD></TR><TR><TD CLASS="quote">

How much compression are you running?</TD></TR></TABLE>

stock LS, but Howard might be referring to my future setup which would be 9.0 JE SRP pistons. Don't let me give you the impression I'm saying 18psi is a rule of thumb regardless of turbo size, compression, ignition timing, etc. I was simply stating for my (future) LS setup, (t3/t04 54 trim, hondata, 9.0:1 compression) that Howard said 18psi was the threshold.

Personally I have no experience with high boost, so I'm curious as well, which is why I asked him. He knows and works daily on Honda race cars, and I trust his judgement.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 11sec.sleeper &raquo;</TD></TR><TR><TD CLASS="quote">is it by psi or whp you be limited? </TD></TR></TABLE>
There are a ton of factors that have to be considered, but boost level is not really one of them...

 

The limits of pump gas are going to be compression, timing curves and amount of boost. They are all analogous to one another when it comes to how your engine performs with said octane rating. Lower compression engines with conservative timing curves can run more boost, then a higher compression engine with aggressive timing. You cant apply a simple rule, its something that the tuner needs to be able analyze, decipher and apply to the engine/tune he/her is tuning.

 

I wanna get mine tuned to run pump gas also. Most of you people have 9:1...9.5:1 compression. Im starting to think my compression is to high. Im running 10.5:1. Is that to high?

 

then you have to deal with tradeoffs, like is it worth running the extra boost over pulling the timing to keep knock away..

i think displacement, combustion chamber/piston dome design, compression, turbo size, and intercooler size are probably some of the larger factor in determining HP output.

It seems to me now, many people have been able to make around the 350-400 HP mark on pump gas.

With 10.5:1 compression you aren't going to see a lot of horsies on pump gas, but everything is reletive... 400 HP isn't anything compared to 800 .. etc.

Typically the lower the compression, the more power potential on low octane you can have (many other factors of course.. but _generally_) the ability to make more power, because you can remove the heat from the air AFTER it is compressed, not someting that can happen once it's in the combustion chamber :-)

bottom line, don't get too greedy on pump gas, and we (at least i) don't live in a country where high octane is readily served at the pump for an inexpensive price. it's simply not worth it to run so close to detonation that one dollar of bad gas here could cause you an engine failure.

oh yea, FWIW i bet the general concensus will be 350-400 WHP safely on pump gas assuming proper intercooler etc.

you COULD go with propane injection and run tons of boost on pump gas. it's a proven system, and very inexpensive for the gains.. especially in the long run IMHO.

Damnit i need to stop it with all this writing i'm starting to annoy myself

 

i guess what i really wanted to know is whats the most horesepower people have seen on pumped gas?

 

..this is a very tough topic.
I love seeing all the posts with high dyno numbers but I think its total entertainment. Most likely, if they are over 500whp, they're not using pump gas

High comp = less potential to run high boost, but you can run less boost on a high comp motor and produce power = to a low comp motor with moderate boost (keeping in mind there is a limit ..pump gas).

With high comp, you'll get better lowend pickup, turbo spools up quickly, but tuning will be edgy

You dont want that under the changing conditions (including the rising temperatures with stop&go traffic). High comp = more chances to detonate.
Id say with 10:1, it'll be hard to see 400+ whp with pump gas.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lazerus &raquo;</TD></TR><TR><TD CLASS="quote">
you COULD go with propane injection and run tons of boost on pump gas. it's a proven system, and very inexpensive for the gains.. especially in the long run IMHO.</TD></TR></TABLE>
Got Propane accessories?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TurboDANDEE &raquo;</TD></TR><TR><TD CLASS="quote">i guess what i really wanted to know is whats the most horesepower people have seen on pumped gas?</TD></TR></TABLE>

Well, ATI is making around 1050 RWHP on 91 octane, but that's a whole nother story 9:1 compression 1.8, I'd say 400 WHP would be a safe limit for 93 octane.