Max boost on pump gas?

[John B]

I have a really good three-core IC. How much boost can I get away with on pump gas? 2.5 Swirl head.

[Frank]

Cannot accurately answer that. It depends on how hot your turbo gets, how much your IC can cool, how much fuel you put in, how efficent your setup is, how much timing, etc. You can run lots of boost if your timing is week. You could probably get into the high teens without worry if you are able to at least properly tune the fuel curves.


Frank

[turbovanman²]

Also depends on what octane you can get. I could run around 20 psi on 94 octane with a 3bar cal, T3/T4 on my van.

[BadAssPerformance]

Pump gas? I just got 100 octane at the pump the other night ;)

[GLHSKEN]

It's all in the tune. The answers given are all dependant on it. I've gone as high as 22psi no issues. Take it slow and check plugs often.

[turbovanman²]

It's all in the tune. The answers given are all dependant on it. I've gone as high as 22psi no issues. Take it slow and check plugs often.

Or pull a Simon, say f8ck it and keep her pinned, :partywoot:

[GLHSKEN]

LOL... I've done that too!!!

[Rattlesnake]

Cooler intake charge allows for more boost. I was running 36psi on 93 and an extra 5 degrees and a custom aggressive cal. All that with water/meth injection. Without it I couln't go over 18psi because the knocking was very bad, regardless of how much fuel I added. Since I only use the car for the road course and I did some more upgrades, now I use 100 octane. I did track days for 3 years with the older setup on 93 boosting 36psi with water/meth and never heard a knock again. It has been 5 years now and it is still the same long block with new upgrades.
http://www.turbo-mopar.com/forums/photopost/data/514/medium/09-04-2006_04-54-50pm.jpg
This is with my older set up.

[DBB mini]

Both the van & shadow I own run 91 octane. Both are stock computer cal. 12-14dg initial timing. Shadow runs 20 psi boost on a stock Garrett TII & a double stocker IC, RRR, 5th injector, stock 88 2.2L TII. Van runs 24psi boost on Garrett GT2871R turbo, double stocker IC, RRR, 5th injector, 2.5L venolia forged pistons, ported swirl head, stainless header. Both have 3" exhaust. Both run +40s injectors with AFPR set around 30 psi. Both run front mount IC's. RRR comes on around 15psi of boost. Never had a problem with detonation, but like Ken said, take it slow, check your plugs after every lb of boost. I also suggest an A/F ratio guage, wideband if you can afford it. Narrow is better than nothing. Dawes, etc.:thumb:

[Russ Jerome]

I have a really good three-core IC. How much boost can I get away with on pump gas? 2.5 Swirl head.


Stock or a calibration, if a cal full timing advance would be the most
important things to consider (assuming fuel and timing bases are cool).

A stock cal can peter out at 15psi or run 20 psi with nothing other than
a good cooler. Depending on the cal a s-60 can break 4 pistons at 16
psi, a good cal 26 psi on pump gas. Highest I ever safely run on pump
gas (94 oct) was 24 psi with a triple core and a old Maxxon cal with
timing soft and fuel set at 10 index.

[John B]

Thanks for the info. I have an S60 turbo, +40s, F2 cam, Menegon head, Venolias, two-piece intake, 52mm TB, 255 Walbro, 3/8" fuel line, AFPR, RRR, graingered, 3" exhaust from SV to exhaust tip. The cal is an MP Performance for the '91 T1. I did the cooling mod and have double cross-drills in head and block. The gas here is 93 octane. I want to use 21 ponds boost if I can get away with it.:amen:

[turbovanman²]

93 should get you 21 psi. If not, theres always ALKY, :partywoot:

[Directconnection]

It's all in the tune. The answers given are all dependant on it. I've gone as high as 22psi no issues. Take it slow and check plugs often.

Yuppers.

One friend was running his S60 clone turbo at 23psi on pump gas w/out issues. He was running the stock T-II cooler as well. But, after 5,000 miles, the hypereutectics let go.

I think Aaron is the one to go the farthest on pump gas and no alcohol injection so far at the tune of what... 379 whp?

I have a friend right now that bought my other friend's project car that we had been working on. It's a 2.2 w/swirl head that I did a basic port job on (stock valves) and nothing more except for the addition of a REAL S60 turbo and 3" exhaust. FWD S5 cal with the base down at 50 and 20psi boost on 93 octane it made 271whp. This is on the original stock pump, too. The a/f climbs as rpms go up, so I assume his pump may be right at the ragged edge and cannot flow enough volume to support much more boost. We'll see how much more they can go without adding any race gas. I think the "safe" cal will allow much more boost, but at the sacrafice of some HP.

[Dave]

I definately would add an alky. injection kit. You can run lots of high boost on pump gas all day.

Also, don't just focus on turning the boost up. Tune everything to meet the max efficiency of your setup. Say at 18psi you're at 15* advanced, you make 250WHP. Now you back off 1* and gain 13WHP just by backing off the timing. I've seen lots of people gain HP by not even touching their boost.

[Speedeuphoria]

Say at 18psi you're at 15* advanced, you make 250WHP. Now you back off 1* and gain 13WHP just by backing off the timing.

I think your confused

the only way that would make sense is if you were getting knock. More timing = more power(till the point of detonation)

[Dave]

I think your confused

the only way that would make sense is if you were getting knock. More timing = more power(till the point of detonation)

Beh, yeh I meant that if the engine is knocking. I don't understand why folks run ungodly amounts of boost when there seems to be more power in tune, other than lots of fuel and boost. Of course it's all after a point is broken where you raise the boost so much it starts pulling lots of timing. I've never personally found more power in tune, but I learned how to read good. ;)