How much boost is safe on 94 octane pump gas?

[NJVetteGuy]

Now that I can finally build boost, how high can I take it up to? I'm running Sunoco 94 octane, stock chip, no cat and a big neck IC. I was told I could run 20, but want to hear everyone else's opinions.

Thanks,
Artie

 

[kenny]

Use a scantool.

Turn it up until you see knock.

Then turn it back down.

Shoot for ~780 o2's in 3rd.

... and ditch the stock chip.

 

[NEARING]

Originally posted by NJVetteGuy
Now that I can finally build boost, how high can I take it up to? I'm running Sunoco 94 octane, stock chip, no cat and a big neck IC. I was told I could run 20, but want to hear everyone else's opinions.

Thanks,
Artie

I don't think I'd try 20psi with your combo and pump gas.

More like 16. Every car is different but I wouldn't do 20 on pump gas without a scan tool for sure.

 

[turbo2nr]

The cooler the ambient air, then a little more boost could be used. 90F outside, 16psi. 40F-50F outside and a front mount, then maby 19psi? But you should be using a scon tool to mess around with this.

Scott

 

[TurboDave]

Re: Re: How much boost is safe on 94 octane pump gas?

Originally posted by NEARING
I don't think I'd try 20psi with your combo and pump gas.

More like 16. Every car is different but I wouldn't do 20 on pump gas without a scan tool for sure.

I agree, especially with the stock chip. It's timing is far too high to run 20# of boost even with 94.

I am safely running 20# of boost on 93 octane with NO knock, but that's because I choose to run lower timing chips (19°).

You might consider looking into a better chip.

 

[murphster]

I'd agree... thats too much boost for the chip. I'd stay with 16.

If those are 30# green strip injectors and you are running high octane with high boost, also keep in mind that you can lean out in 3rd so you may want a chip with low timing in 3rd to help out. You can also add fuel pressure to help out the leaning out in 3rd. This will probably only come into play when you start upping the boost to 20 lbs or so (which you shouldn't do on 94 octane anyway). On 100 octane unleaded I can run 21-22 lbs boost without knock on a similar combo, but the fuel pressure is raised and while the timing is higher than stock, it isn't very agressive.

 

[strikeeagle]

My car hate pump gas, Sunoco 94 included. Couldn't even run 16 or 17, even with a 52, and FM and every other bolt on known to man.

I would never tell anybody 20 on pump gas - that's a recipe for yanking the motor. This isn't to say a few folks haven't managed it. But it's unusual, and takes one eye on the Scanmaster at all times.

 

[bruce]

Originally posted by NJVetteGuy
stock chip

14-15 PSI.

Like's been mentioned get a scan tool so you can see what the engine's doing.

 

[Tommyg]

I have the scanmaster installed but don't know how to read it for knock. I also have a boost guage but don't know how to hook it up so it's sitting on my work bench. At this point I don't even get on the car in fear of doing it damage. I need some technical help!!

 

[turbo2nr]

Enroll in a twelve step program.
Step one, learn how to read the scanmaster, and what numbers you are looking for.

 

[boosted]

i tend to agree with all thats said..first off...learn to read the scanmaster..once you learned whats what tune your car with it...you'll find no two cars will act alike with the ame tuning but it will give you a baseline idea of where to go..i found that with the stock turbo and stuff my car ended up likeing 19# of boost with 94 octane and some octane booster..but that will differ from car to car. lots of factors, air density where u live, temp.. cool nite or warm day etc...with your scanmaster u could should be able to factor all this in and be able to come up with a happy medium for your car....

 

[NJVetteGuy]

I run WINALDL with the homemade cable or my snap-on scanner. I get no KR at 20 lbs, when we have a cool night like last night, but with the warm, humid air today I could only run 17. I'm running pig rich(O2s were 920-940mv ) so I think I should just install the 009s I have and try some of the chips I have(2 street and 2 race). I just wanted to get the car running right before starting the mods, it looks like the car is running ok now so it's mod time. I'm going to install the 009s, install the stock headers and get a bigger turbo on this thing.

 

[TurboBuckeye]

Originally posted by Tommyg
I have the scanmaster installed but don't know how to read it for knock. I also have a boost guage but don't know how to hook it up so it's sitting on my work bench. At this point I don't even get on the car in fear of doing it damage. I need some technical help!!

Technical Help

 

[77tech9]

I can't even run stock boost levels on the gas down here (91 octane).

But once you put racing fuel in, 19 psi here i come!

 

[galoush]

I run 20 -21 on pump in my car now but the timming is at 20 deg . I think the timming is going to be a big factor of what you can do , plus ported head cars or cammed cars factor in alot i think. There are so many different variables IMO . Tuning with the scanmaster is going to be your best bet if thats what you have . I know in the winter i have to lower the boost a bit too .

 

[turbo2nr]

Why do you have to lower boost in winter? I can raise my boost when it gets cooler outside!

 

[galoush]

The car gets leaner , i guessing with the cooler air its making more HP that and the winter gas is a different formula and picks up more knock at the higher boost on the pump gas.

 

[turbo grey]

Its all in the chip.I'm using a turbotweak chip from eric mashall,with 19*timing,and
running 25 psi on 94 pump gas.I'm running a pt-72 turbo 0 knock,780 02's,and a big smile on my face..His chips also have parameters u can adj to fine tune your combo,such as low boost timing,wot timing,and wot fuel trim.