This is for those guys in the 12+ range, at what point do you need alky or race gas? Right now I am seeing 15 psi on my gauge, on 93 octane. So far it seems to like it, but I need to pull the plugs and see how they look.
My comp is right at 9-1, so that should help quite a bit.. and I am still running the stock LT1 cam. I figure when I get a turbo grind that I should be close to the edge, so what's everyone elses thoughts?

 

Im at 13 psi, 383 ported heads cc305 9.0 comp p1sc, ati twin highflow IC. no problems on pump gas (98oct = youre 93-94) have run it at 31 degrees timing at the dyno 600rwhp...
My friends car 383 ported canfields cc305 9.0 comp BIGGEST fmic i have seen D1sc same fuel as mine 25 degrees timing 17psi no problem.. havent dynoed it yet.. We gonna dyno hes car whit a 50/50 mix 98/race fuel...
Its all in how much timing/power you wont

 

What size pulley are u using to get to 13psi on a 383 with ported heads with a P-1sc. Lisa

 

My timing is retarded with a MSD6BTM; right now my WOT numbers are 36, minus 1 deg/lbs of boost, so I should be around 22 at 14 psi. I also have twin FMIC, at 6 psi I was seeing zero increase on my IAT's, haven't checked them yet with the increased boost, may do that tomorrow.
Thanks for the reply Lisa, I was just curious what others are getting away with.
I DO know traction has become an issue on the street.. Hoosiers are crying the blues!

 

7.65" and 3.1" reving the engine to 6000-6100 revlimiter set on 6300...
And yes, i have trouble whith slipping belt
The heads are "mild" ported...
Going for ported trickflows and custom cam for next season and planing to reinstall my 3.3" pulley and rev the engine to 63-6400, had no slipping problem whit that pulley...

 

depends on what sort of detonation/pre-ignition issues you run across..i know some people making ~700rwhp still running 93...while others who try to squeeze every bit of timing, and pound of boost out of their setup, who end up having to run 100, only to make 500rwhp....

 

How far are you willing to push pump gas? Would alcohol injection be a possibility for you?

Just as an example: when my GN's engine was stock(~8.7:1 CR) i could run up to 17psi of intercooled boost on 93 alone with a TA-49 turbo and 36# injectors. This was with an "18*" chip (not sure of the actual timing tables). With the alky kit installed i could run up to 25psi before it started to show knock counts on the scanmaster. So alky alone netted me 7 more psi and a huge SOTP improvement. About 25psi seemed to be the limit with alky injection on most TB's. Then propane injection came along and now many of the buick guys are running upwards of 30psi on pump gas(with larger turbos and supporting fuel mods, of course). About all these guys don't even use race gas anymore because they can run almost as much timing and boost and get near or better results. Plus the alky only runs when needed. A 2 liter tank would last about 7-8 runs down the 1/4. The SMC kit i'm using only costed about $320 when i bought it new(there are better progessive kits out now) and most assuredly saved money in the long run over that $5/gal race gas.

I've seen a number of boosted mustangs have great results with it too..... so it could be what you're looking for if you never considered it before. HTHs

 

Actually, I am planning on an alky kit when I get the turbo cam. So I had hoped to have zero issues at the 15 psi range on pump gas.

Might even be able to go to 20 psi or so, for the track only.

I will add unleaded race gas for the spray; I have a 100 shot on it for a little added "pop"!

 

Sounds good. I'd recommend the newer progressive kits that allow you to increase injection volume relative to boost. My kit only has adjustable turn-on point and pump speed (static, it sprays the same amount all the time while it's running). Works great even though i get a little sputter when it first comes on (at ~15psi) b/c it's injecting more at low boost than is needed. Other than that it's great.

One thing about propane injection is that it works slightly better than the alky, while lasting a long time. One guy on the TB board who developed the kit did a LOT of testing and running (street and track)... the tank lasted him over a month!!! Others are reporting extensive times between fill-ups too. Under the conditions i run my car it probably would last 2 months or more. And as cheap as propane is, it'll pay itself off in no time. My only quirk with it is that i don't want to get in an accident with a full tank back there

 

An intercooled, 9:1 stock cube setup should be able to handle 12psi with 93 pump gas and no alky or race gas. Can 15psi work? It's hard to say, what are your IAT's at the top of the track or during a dyno pull? On the dyno my IAT's were like 105F but at the track they were like 140F since my track passes were thru all the gears.

I think 15psi, decent timing, decent FMIC or A2W, on 93 pump w/o is possible but I would not base it off the dyno I would base it off the real world. I personally think that 15psi will be on the edge. For an LS1 stock WOT is ~27 degrees. If I were to try to find a 15psi pump gas tune I bet my WOT timing would be in the 16-20 range with 11:1 - 11.5:1 AF. The issue is when you make the same power at 15psi with 16 degrees of timing that you make at 12 psi with 24 degrees...

 

Well I did a test pass and logged it thru the DFI..
outside temp was around 90, iat started at 110 and went to an indicated 158 at 16.3 psi. O2 readings on the heated DFI O2 sensor were around .777-.806.
The a/F gauge I have stayed at slightly rich the whole run.
Timing was an indicated 34, my MSD pulls out 1 deg/lbs, so figure 18 degs timing.
No hickups, pulled very well, but I plan to pull the plugs to see how they look. There is no knock sensor on the car.

I have a stand alone wideband I plan to put on it, and tune for 11.5 or so at WOT.

I think with a dedicated turbo cam I'll need to add alky, but it seems to be fine with the stock LT1 cam for now.