Hi guys, Maybe I'm going crazy but I've searched and it seems that everybody else with a t-78 have had more hp at the same amount of boost. One problem is my turbo is from a supra....the exhaust side is huge....could this be a factor? I know people are going to ask me what I have but its too much to list.....I've done it all! I appreciate all feedback good & bad. Thanx

 

The exhaust side on the Greedy turbos are normaly larger on the rx-7 than on the supras. The large turbine will only help you make more power especialy at higher rpm.

 

Well then why does my turbo start to hall a$$ at 5000-5200rpm. I've searched and most people say their turbo's start to spool at 4200-4500rpm's. Way too much lag here.

 

A dyno sheet sure would be helpful here!

Do you know the exhaust A/R and trim?

 

The lag is not responsible for the lower HP numbers you are claiming to be low. I thought your original question was about low power output at the same boost. Like I said before if anything the bigger turbine section would give you more HP not less.
BTW. Your idea of 'starting to haul a$$' might be different to others when they say 'start to spool'.

 

yeah my t66 starts to feel great around 4OOO then at 46OO its in full boost and at 55OO my car is hauling serious ***

I think you do have a problem with your tuning because I have a .7 exhaust side on my turbo and 1O.5 a/f ratios for a good amount of the rpms and it put out 38Orwhp on a hot day at 15psi without the water injection stock engine...4O5 is a ton of power though!

care to meet up with a few other rx7s owners during christmas break? ill see what I can get together hopefully like 2 others

 

Thanx for the input crispeed. I was sort of saying that, yes they are low(HP #'s) compared to others. But the the lag also concerned me. It does start to spool at lower rpm's though full boost is reached around 5000-5200. Hey surge, that sounds good. I missed out on the tampa meet cause my car was at the shop and stuff came up. Let me know.

 

Superman: I was there at Secret Services when Scott was tuning your car. We'll have to get together some time.

Surgemonster: His car is super-light, so it's gonna haul ***!

 

ohhh no wonder the hp numbers are low scott is tuning your car lol why didnt you say so? Seriously though thats the deal

umm my car gets full boost at 47OO so 52OO is understandable for yours...

I didnt go to the tampa meet I go to school up at UF

any way scratch the meet I just wanna race both of you guys...im gonna mark my car with a #1 on the rear glass though so we know i beat piano cause our cars 'look' the same lol

 

Well, don't know if this pertains to you but i only got 415 at 20psi. This was with a stock port reman. I think with bigger ports you might get more power. Are you on stock ports?

 

my car made over 400rwhp @ 10psi after slight tuning....... with a T78 kit of course, my car was not the norm though. al's car should now make similar power to what mine had

 

vosko, what porting did you have to make that power at 10psi?

 

judge ito spec largest possible street port and built motor by him

 

i make 403 rwhp at 19 psi, I would say its all in the tuning. I am very happy with the 403 rwhp at 19 psi on the t78. It is a little on the low side but, I like that it is a little on the rich side, so i am not that worried. i cant even drive the car with 403 rwhp on the streets, i get no traction. i keep the boost at 13 psi, and my max boost is at 17 psi. Maybe when i get to the point where i need the higher boost to win races, i will get the car tuned better. But that isnt the case!
adam

 

Holy cow. Wtf happened to your car Vosk? You parting out? I'm interested in the rims since Ray took his back. I need an interior too.

 

al you forgot our conversation already jeez LMAO

the car is wrecked! i would sell you the interior but a guy is buying the rolling chassis. i have two sets of rims. i'll talk to you when you go by the shop or CALL ME

 

Thanx for all the info guys, I greatly appreciate it. I'm happy with 401hp, I was just wondering because of alot of other people were getting higher #'s. Fastcar: I hear you....I gets no traction at all...its pretty scary. I'll have to go buy some stickier tires now. al900rr: I've got a mild street port. At the time I just wanted a little more power when I had the twins. I wish I would have went all the way but owell its fine I think. Vosko: Thats some insane power #'s. Probably some crazy a$$ porting and perfect tuning. Piano: Yes, we should hook up one day. My car does'nt get out much. I work like crazy hours and there has been too much rain lately. Your car looks very nice if I might add. Thanks again guy's!

 

just remember with buying stickier tires, and having that much power, things start to break. The first thing that will prolly break is the differential. If that breaks go with the kaaz 1.5 LSD. I hear its almost unbreakable, and it frees up even more power. KDR was telling me how one guy got 30 rwhp out of changing to the kaaz.

 

my tuning was CONSERVATIVE at best......very rich 10.00 AFR

 

does the graph look anything like the one where you hit ~459 @ 15 psi? IIRC you were running stock plugs? It looked like to me on the 15 psi run you had ignition breakup, a lean condition, and a spike in power. I'm sorry man, I'm just skeptical. I would only believe it if you repeated it on seperate runs on a different dyno. I think there are too many variables in favor of it just being a one time fluke....

not a flame...I think that 459 is very possible at 15 psi on your turbo. Hell, people have made close with a T04S, but your graph only shows a quick spike to that level IIRC and not a somewhat smooth slope up to it.
"over 400 rwhp @ 10 psi" is pushing me to raise an eyebrow and ask....I would really love to see the sheets....and that is not said sarcastically.

 

I think that that is pretty low power and slow spool for a Greddy T78 if you have a good sized port on your motor (missed it whether you do or don't). Even on stock ports, I would expect around 400 @ 15 psi though....but maybe similar spool up time...

I'm not even going to begin to guess what the problem might be.....too many variables and too little info...

 

actually it made 415 @ 10psi



i was using stock plugs and it was tuned for 10.00 AFR sooo anyway

 

SAE corrected?

 

here is my dyno #

 

is that ignition breakup in your graph jon?