How much boost will I be able to run on straight 93 with this combo?

[d0n_3d]

The car is pretty much finished except for a couple things...wanting to know what will probably be the highest boost level I can run without knock with my new combo:

PT61 P-trim, S-cover, internal wastegate
65 lb/hr high impedence injectors
3500 PTS 9/11 stall
bone stock motor with valve springs and timing chain
3" THDP
PTE front-mount intercooler
stock throttle body and plenum, rjc powerplate
extender chip with translator + box...probably will run 18-20 degrees timing at first

I actually have the SMC alky kit but will be having some down time with it because I want to swap out the controller to a progressive style...

anybody have an idea? 18 psi? 20 psi? 15 psi!?

 

[FlyinGN]

every car is different.. Some can support 20 psi some 15.. My Gn can run 17 psi on Sunoco 94..

 

[NEARING]

16-18 depending on timing, IMO.

 

[ijames]

Every car is different but I'd expect 20-22 psi with proper fueling and 20 deg timing, in 3rd gear. That's based on the front mount and efficient turbo.

 

[JDSfastGN]

Originally posted by ijames
Every car is different but I'd expect 20-22 psi with proper fueling and 20 deg timing, in 3rd gear. That's based on the front mount and efficient turbo.

I really can't see 20-22 on pure pump gas, especially with a lot of 93 being of lower quality later, i think 15 would be safe to start off, and maybe you can pull 17-18 in the lower gears with out a problem. On a thrasher and stockish combo i used to be able to run 21 in first and 19 in 2nd and third, now with my current combo, i can't run more than 17 before it knocks.

 

[OneLethal87GN]

Why would you have down time with a controller swap? Did you have to send in your old to get it upgraded or something?

 

[d0n_3d]

Originally posted by OneLethal87GN
Why would you have down time with a controller swap? Did you have to send in your old to get it upgraded or something?

well the car isn't running right now...but I am going to have my controller sent out to be replaced with a progressive controller...until I do that I don't want to exactly cut holes in my intercooler piping right away with my new front mount...just want to get the car tuned and running perfectly before I start to get on it hard...thus why I was asking how much boost on straight 93

 

[ijames]

I really can't see 20-22 on pure pump gas, especially with a lot of 93 being of lower quality later, i think 15 would be safe to start off, and maybe you can pull 17-18 in the lower gears with out a problem. On a thrasher and stockish combo i used to be able to run 21 in first and 19 in 2nd and third, now with my current combo, i can't run more than 17 before it knocks.

You have to tune up to it, carefully and slowly, but I've been running 22-23 psi in 3rd gear for 5 years now, ever since I got my PTE54 turbo (a tic smaller than the original poster's GT61 P trim), with a bone stock long block, V2 front mount and fuel system/injectors to match. Last December I moved up to a P trim GT67 4" inlet turbo but couldn't run any more boost. That's all on the poor 93 we get here in MD. I've driven to states with better gas several times and got the expected 10-25% increase in mileage but never had the chance to retune to see if I could do better. A couple of local friends with similar combos (plus bigger turbos and good heads) have run at least 22 psi in 3rd with no alcohol. Obviously the better heads let them flow more air at the same boost, but I really don't know if that lowers the max boost that can be run at a given octane, or not. I would bet that stepping up from your TE44 to a 6x turbo would let you run at least 2 if not 4 psi more on 93 octane, and get the better mph to go with it. Whether or not your et actually improved would depend on your converter and traction, of course. When I went from a TE34, one step smaller than a TA49, to the PTE54, I moved from 19 to 23 psi in 3rd gear on the same 93 octane gas. One key is delivering the fuel; 50's are only enough for 12.20's to 12.40's on 93 octane in spite of their 10 second potential on race gas and high timing. Most guys don't really tune up for 93, they run race gas at the track and live with 93 on the street with everything turned down. I run 100 octane unleaded less than once a year and have never run leaded stuff; I keep my 93 tune as optimized as possible at all times.

 

[NEARING]

Originally posted by ijames
You have to tune up to it, carefully and slowly, but I've been running 22-23 psi in 3rd gear for 5 years now, ever since I got my PTE54 turbo (a tic smaller than the original poster's GT61 P trim), with a bone stock long block, V2 front mount and fuel system/injectors to match. Last December I moved up to a P trim GT67 4" inlet turbo but couldn't run any more boost. That's all on the poor 93 we get here in MD. I've driven to states with better gas several times and got the expected 10-25% increase in mileage but never had the chance to retune to see if I could do better. A couple of local friends with similar combos (plus bigger turbos and good heads) have run at least 22 psi in 3rd with no alcohol. Obviously the better heads let them flow more air at the same boost, but I really don't know if that lowers the max boost that can be run at a given octane, or not. I would bet that stepping up from your TE44 to a 6x turbo would let you run at least 2 if not 4 psi more on 93 octane, and get the better mph to go with it. Whether or not your et actually improved would depend on your converter and traction, of course. When I went from a TE34, one step smaller than a TA49, to the PTE54, I moved from 19 to 23 psi in 3rd gear on the same 93 octane gas. One key is delivering the fuel; 50's are only enough for 12.20's to 12.40's on 93 octane in spite of their 10 second potential on race gas and high timing. Most guys don't really tune up for 93, they run race gas at the track and live with 93 on the street with everything turned down. I run 100 octane unleaded less than once a year and have never run leaded stuff; I keep my 93 tune as optimized as possible at all times.

I wish I knew as much as you've forgot!