I know its impossible to get an exact number, but any guesses as to how much power my 6262 tt ecu set up would make on 10psi with stock hg and 3 inch single exhaust on an auto tranny? Just curious. I will also get mine dynod when my tuner finishes the tt conversion. Ill even post a video.

 

when i had mine on the dyno at 8 psi around 4k rpm it was hitting just around 300hp so i didnt run it any harder given the stock auto. not sure what power will be with the tt ecu, hopefully the same just alot smoother. can usually get a tt auto trans for $400-500 on your favorite auction site if you want more power but keep it mostly stock. the headgasket probly cant take much more than that i wouldnt think.

 

should be over 300whp but the auto it varies some.

Milon on SF got to like 600whp on the stock headgasket but he has a lot of mods and an alpha tune.
Its all in the setup and tune, I wouldn't be surprised if one could boost more than we say is generally ok on the stock headgasket since the gte ecu is a bit better than the ge ecu, but you won't hear me recommending you to crank the boost on the stock headgasket with pump gas to find out, seriously I would not recommend that on pump gas generally speaking.
But the problem isn't actually the stock headgasket the problem is the compression and the pump gas, the gasket itself is arguably stronger than a gte gasket because it is only 1 layer, so the gte gasket has more places to leak from as it is muliple layers.

 

So what your saying is gte ecu+ Race gas+ stock head gasket = profit?

I saw a couple people on supra forums running stock head gaskets at about 10psi, I thought anything over 8psi was just considered reckless.

What mods support boosting with our stock compression?

 

oh boy, i'm having mine cranked up to 10psi on a stock HG with a manual boost controller. I hope I dont mess anything up. But I will be running it on a dyno sometime early next year

 

it used to be considered reckless, and with the GE ecu it sort of is still.
It just depends who is repeating what info. Personally I have run 11 psi on the stock headgasket, stock injectors, stock pump, stock ecu, stock everything else literally and made 330rwhp.
when the ecu was not confused it pulled to redline in a beastly fashion. when the ecu got confused, it would tend to miss and a few times I got some very large backfires while boosting.. lol.
I never blew the headgasket believe it or not, but I did get rid of the ecu promptly as I thought I blew the motor the sound was so bad but the motor turned out to be pristine when opened up.

just gotta eliminate the variable that can lead to detonation, and the stock ecu is a huge one.
the gte ecu doesnt ever get confused, so I would say 12-14 psi is probably a better idea of where to stop than the old 8 psi if you have the fuel for it. the stock injectors are pushing it at 11 psi, but when we upgrade to 440's and gte ecu mod, alot of those problems go away. just go a few psi at a time.

only issues I can see with the higher compresion gte ecu wise, is that the jdm ecu's are rumored to have more agrressive timing, which would not be helpfull in that case on pushing it up there.
If it were true you could run a US ecu though and maybe have a better match but the odb1 US ecu has a lean spot in transition or so they say.

I dont think you generally have issues at 10 psi with the gte ecu mod in on stock compression and pump gas unless you get really bad gas in your area. If you plan on pushing it, consider doing the datalogger mod and you can see your knock values.

also 10 psi on stock compression is pretty fun for a street vehicle.

 

thats what i wanted to hear

 

Yeah that is nice indeed, I always thought you HAD to do the head gasket. But since alot of us are transmission limited its not that big of a deal and you can always swap it out later.

Also im obdII so im guessing thats a positive? Can you obtain the knock values through the obdII port?

 

Ali what size turbo did you have when you made that 330whp on stock fuel?

 

im thinkin ill swap the 8psi spring for a 10psi spring in my wastegate once i get my gte ecu/ffim setup going...maybe a fuel controller and throw in my 550s since i have a set from oside when i thought i was going usdm ecu (probably not necessary). i only run chevron supreme pump in my car so whatever that can support.

 

I have those same 550s from oside tiger. I am going with a usdm obd2 ecu. Even with the advice above I am scared of going past 10psi on stock hg

 

ill never go beyond 10psi on stock hg myself either but thats just my power goals and reliability needs for a daily driver. some would argue against that but whatever.

 

Yeah especially with the auto its not a bad idea to max out your setup with the stock compression. I honestly miss the off the line response, but it is nice to run like 18 psi and not worry about it.

I have a xs power knock off 61mm turbo, still waiting for it to go bad or smoke but nada it keeps working fine.

keep the 8 psi spring and get a manual ball and spring boost controller. your turbo's will spool faster because the wastegate wont creep open at like 6 psi loosing precious boost.
when you put the boost controller on, even if you go up only 1 psi, the wastegate will not crack open until the psi you set it at, meaning you pick up a ton of spool by just having one in there, so no need to change your spring. I have like a 9 psi spring as well and a $20 manual boost controller and it keep the boost rock solid at whatever I set it at and it spools much faster than without it. with low psi springs like these they tend to creep alot without the controller.

Just start out low and work the bugs out. 8-10psi is a great place to start you get used to the extra power and when it comes in, and you start to notice all the other problems with your car at that level. like in the rain you can't go more than 1/3 way down on the pedal or the back end starts to slide out, while going straight, not so fun. in the right gear it happens even sooner.
then you will start making faster stops and more of them, you will need ls calipers and rotors at least, I know my SC did not feel safe until I did that upgrade, now I can stop it as fast as I need to.
tires, you will need some good wider ones and wheels to fit them on. try and get a 275 on the rear or better in a good brand or you may be all over the place at times. 255 is the bare minimum upgrade on those.

With boost I always tell people take it slow, once you get used to that power don't worry you will get the itch later on again, but jumping from a slowish vehicle to a 4-500hp vehicle is not something that should be done in one step unless you are used to that kind of power and do all the rest of the supporting mods.

Instead of trying to raise the boost more alot of fun and more power can be put down by doing drivetrain stuff too, like a vlsd will help you use more of the power you already have, same with a better trans, but one thing to remember is wider grippy tires and a vlsd is almost sure to break a weak or limited trans. I am still on the open diff not gonna do vlsd until I go r154 but I am in sort of a break of modding my car I am just enjoying it as is for a little while.

 

My next mod will be an LSD, but I'm not in a hurry just yet. Which one would you recommend for a OEM w58 car?

 

the lsd unit from an automatic TT supra will bolt in your differential, or if you get the whole auto tt pumpkin it will have a lower gear ratio which is usually desired for a turbo unless you are drifting it or something like that. at highway speed your rpm's will be lower which is nice and it gives you more gear to boost with before you have to shift again.

you can use the diffs below and put in auto tt lsd into them except for the 6 speed has a different bolt pattern. that way you get the lsd and you get to choose your ratio.

https://www.clublexus.com/forums/per...ial-ratio.html
92-97 SC300
6 cyl, AT (4.27 ratio)
6 cyl, MT (4.08 ratio)

98-00 SC300
6 cyl, AT (4.27 ratio)

92-97 SC400
8 cyl (3.92 ratio)

98-00 SC400
8 cyl (3.266 ratio)

92-96 MKIV Supra

w/o turbo; (4.27 ratio) Limited Slip
w/o turbo; (4.27 ratio)
w/turbo, MT (3.133 ratio) Limited Slip
w/turbo, AT (3.769 ratio) Limited Slip

97-98 MKIV Supra
w/o turbo; (4.08 ratio) Limited Slip
w/o turbo; (4.08 ratio)
w/turbo, MT (3.133 ratio) Limited Slip
w/turbo, AT (3.769 ratio)
w/turbo, AT (3.769 ratio) Limited Slip