Predict the outcome...

Soush · March 19, 2020

So an update... I got the car dyno tuned, the tuner claimed that on his dyno l83 with a CAI, header and full exhaust with a serious tune got 295-300whp (again their dyno reading was like this). I ended up getting 345.1whp and 420 torque... Now the issue I have is a misfire at 4200 to 5200 rpm... new sparkplugs, wiring, fuel injectors serviced... everything has been ruled out, we increased the transmission oil pressure too to rule that out, same issues.. Don't know what seems to be the problem.

silveradosid · March 19, 2020

have you checked to see what the fuel pressure is, possibly the high pressure pump

Soush · March 19, 2020

So update...

The transmission oil was low as I had the oil transmission cooler installed. The garage had set the right amount when they installed it, but I guess they didnt run it enough to top it off... It was off by 1 liter, so got lucky...

If I were to upgrade to add more HP, what would you guys suggest? maybe 50whp more. No supercharger or turbos though.

flyingfool · March 19, 2020

5 hours ago, Soush said:

So an update... I got the car dyno tuned, the tuner claimed that on his dyno l83 with a CAI, header and full exhaust with a serious tune got 295-300whp (again their dyno reading was like this). I ended up getting 345.1whp and 420 torque... Now the issue I have is a misfire at 4200 to 5200 rpm... new sparkplugs, wiring, fuel injectors serviced... everything has been ruled out, we increased the transmission oil pressure too to rule that out, same issues.. Don't know what seems to be the problem.

interesting.. I'm curious as to what the base run looks like , to compare the losses. I'm guessing your using 1-7/8" long tubes headers, cause that torque curve just looks sad, your usuable torque window is roughly 1500 rpm! : (

my stock truck makes 320hp at the flywheel all i have is a resonator delete on the intake and i wired open the muffler flap, running 91 octane and a 180 t-stat

I would upgrade to the Doug THorly Tri-Y headers smaller primaries 1-5/8" and catless exhaust, BTR stage 2 cam maybe play with the VVT for more low end grunt, it's a truck and they need torque to move their heavy asses, corvette camaros can get away with making high rpm power cause they're light weight

Edited March 19, 2020 by flyingfool

flyingfool · March 19, 2020

your misfire might just be the Torque management cutting in and disabling the power to the ground. on test for this is to get your HPtuners software installed and list all the transmission PIDS in a graph, if your holding a gear and not shifting Torque Mngmnt should not show any spikes on the graph. I have a feeling TM is taking away all your smoke your trying to lay to the ground..

also if you increasing the trans line pressure you need to install the larger boost valve in the pump housing and a few other mods . stock trans should be fine up to 550hp.

i think you need to try taking off 20% detune your TM

Edited March 19, 2020 by flyingfool

Soush · March 20, 2020

7 hours ago, flyingfool said:

your misfire might just be the Torque management cutting in and disabling the power to the ground. on test for this is to get your HPtuners software installed and list all the transmission PIDS in a graph, if your holding a gear and not shifting Torque Mngmnt should not show any spikes on the graph. I have a feeling TM is taking away all your smoke your trying to lay to the ground..

also if you increasing the trans line pressure you need to install the larger boost valve in the pump housing and a few other mods . stock trans should be fine up to 550hp.

i think you need to try taking off 20% detune your TM

The transmission oil was low as I had the oil transmission cooler installed. The garage had set the right amount when they installed it, but I guess they didnt run it enough to top it off... It was off by 1 liter, so got lucky... Had a few good runs on and offroad earlier, all well!!

davester · March 20, 2020

I don't know if you did it, but there is a fairly specific procedure in your owners manual describing how to do it, after getting the transmission fluid to the correct temperature range.

flyingfool · March 21, 2020

i'm sure you had enough fluid otherwise it wouldn't of put down any contact with the dyno.

another PID you should data log is the Throttle body, and throttle pedal, you want to see what your telling the throttle to do is just what the computer is "Commanding" the Thottle to do. once you exceed stock power these two will not be on the same page... not too mention TM needs to also be analyzed