tuning

[12's]

I have a 2g awd with a super 20g, supra SMIC, walbro 255hp, 660's, Safc, Ported exhaust mani., intake, 3" turbo-back exhaust, hallman mbc, slimline fan. I am at 15psi with no tune because I cant get my pocketlogger to work right.
I used the g-tec the other day and it said my max hp was 268hp @5503rpm and my max torque was 261.4 ft/lbs at 5301 rpm. I looked at the whole hp vs torque graph. After I got to 5500 rpm and got my max hp and torque, the hp and torque dropped off a lot. At the end of the gear, it was only 189 hp and I don't remember the torque but I can check if anyone wants to know. Does anyone know why the numbers drop so much and why the power doesn't carry?
Thanks

 

[Blk_99gst]

I think the drop off is just a fact of turbo cars. I'm sure there's reason; stock cams are a problems at higher rpm, intercooler is heating up and producing less cooler air, turbo is running out of steam... Could be several explainations. I just had my car dynoed on Friday; big16g, 3" exhaust, fuel pump, 660's, gm-maft setup, external dump, etc... I made my peak horsepower (279) at 5500 rpm, then it slid down to 200 by the top or 3rd. I have some lean issues between 3000 and 5000 rpm, but that's beside the point.

 

[kpt4321]

Originally posted by Blk_99gst
I made my peak horsepower (279) at 5500 rpm, then it slid down to 200 by the top or 3rd.

Not by that dyno chart it didn't. You don't go below 250 whp.


Horsepower dropping up top can come from many sources; bad tuning, stock cams, heat soak, knock retard, etc...

 

[Blk_99gst]

kpt4321 - You're right; I got confused when the lines crossed and thought the hp one was the one that went down. Opps. Thanks for pointing that out.