jimbo1111

what is the max amount of boost one can run on pump gas? lets assume we have enough fuel.

rage2

Depends on the turbo, the intercooler, many factors.

Alan C.

With the right timing, fuel delivery intake charge temp I have run as high as 20 psi on pump gas. Adjusted the timing and fuel and lost a few hp.

I have run a complete DE weekend at 18 psi on pump gas with no problems. That was with a dyno tuned Tec3 program.

Alan

rage2

Alan, what's the most timing retard you have run? I too have run 20psi on pump fuel, but at a total ignition advance of 9. At this level, EGT's must be through the roof (I have no EGT meter). The car's fast, but i dunno how reliable it is =).

At total ignition advance of 18, I can do 13-14 psi depending on air temperature. I think a bigger intercooler should be my next upgrade, allowing more boost on pump fuel.

Curious, what octane is your pump fuel? Mine's 91 octane. Some stations offer 92 octane, but I have yet to see a difference between the two.

jimbo1111

alan c. do you think i can get 18lbs boost on a dyno tuned maf ? pump gas , stage 3 sfr turbo,52lbs.injectors,46mm tial wastegate,stock head and lower half.

jimbo1111

rage we have 93 octane at sunoco in ny

jimbo1111

i think the best way of making lot of hp is the turbo. we need a turbo that can spool quickle and give us a high rate of cfm at low psi to keep us in the safe zone . dose anybody agree.

David Salama

Can someone explain how ignition advance works to increase performance, decrease preignition, etc. I've always been confused with this. Is there a way to change the timing with the stock DME? I do have fuel adjustablility with my ARCII, but the computer handles the timing?

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Alan C.

Rage,

I,m running 19 degrees on 100 ocatane at 21 psi. I ran 17 degrees on pump gas,93 octane, at 18 psi.

At 3400 - 6850 rpm it looks like this for 100 octane:

Boost/Advance Deg.
0/36
2.7/34
4.9/32
7.1/30
9.2/28
11.4/25
13.6/23
15.8/21
17.9/20
20.1/19
22.0/19

Fuel pressure static set at 43 psi for 0 boost. Pressure rasies 1:1. 83 lb. injectors pushed by a big Weldon pump. Tec3 management.

Steve Lavigne

[quote]Originally posted by jimbo1111:
<strong>i think the best way of making lot of hp is the turbo. we need a turbo that can spool quickle and give us a high rate of cfm at low psi to keep us in the safe zone . dose anybody agree.</strong><hr></blockquote>

No

Alan C.

Jimbo1111,

I think you can get 18 with your setup. I would put it on a dyno and look at the air fuel to be sure. Watch the A/F on the dyno while doing the run. I use a post-it note with an arrow to indicate on the monitor where I want to abort the run if it goes lean.

Alan

Alan C.

jimbo1111,

If you flow more at lower pressures to get to the same hp you still need fuel. To flow more at a given psi you need to upgrade: head, IC, intake, exhaust and THEN match that to a turbo.

You could do it a piece at a time but you would still leave a botle neck each time.

Depends on what you want to do. There are a lot of really fun 280 - 300hp 951's out there. They last and don't kill the budget. Products from Danno, Tim, John, Lindsey to name a few.

Alan

jimbo1111

thanks alan . is it true that i sould start out rich and then start to lean the mixture to get the proper 12to1 a/f and at what rpm sould i see 12:1 a/f. i don't think a maf is designed to give me a 12:1 a/f mixture through the whole rpm range .i think i'll be rich till the higher rpm then start to lean out. what do you think and what sould i do.

Russ Murphy

[quote]Can someone explain how ignition advance works to increase performance, decrease preignition, etc. <hr></blockquote>
David, try reading these two tech pages form the SDS website. They're pretty informative.<a href="http://www.sdsefi.com/techcomb.htm" target="_blank">Ignition and Combustion</a><a href="http://www.sdsefi.com/techocta.htm" target="_blank">Horsepower and Octane</a>
[quote] Is there a way to change the timing with the stock DME? <hr></blockquote>
Yes, with the fuel quality switch, but it's not really useful (in most instances) as a performance enhancer.
[quote] I do have fuel adjustablility with my ARCII, but the computer handles the timing? <hr></blockquote>
Yup.

Ahmet

Completely stock except boost set @ 19psi, turbo back open exaust (3 inch) intake and europroducts chips. No problems in almost 5k miles. There's a loss of power issue at the moment but it's doesn't appear to be internal.
Ahmet