New Bolt Ons, Torque Loss?

[aleccesarenriquez]

I'm having issues with some new bolt ons.

18 manifold with harness, TSP long tubes, GT350 CAI, 47 lb injectors.
Flex fuel tune

Here is my dyno:
https://imgur.com/a/fLtEaNZ

Torque numbers are low but so were base torque numbers (poorly calibrated dyno?). With everything I gained 80/50.

When I saw the graph obviously I was very excited.

However now that I've been driving it for a while, the car feels strange.

Above 5k rpm it feels pretty good. Pulls pretty hard and obviously revving to 7.5k is great. Any rpm lower than that though, the car feels pretty dead. For example, if I'm trying to pass anyone on the highway, if I drop it to 3rd around 4k rpm and step on it, the car screams but goes absolutely no where (like it literally feels like a normal car acceleration at 4k). It felt much stronger before between 2k-4k rpm. I get that maybe the power band shifted, but according to that graph, there were still gains in that range so should I still be feeling slower?

Does anyone know what would cause this sluggish feeling? Could it be the harness? Tune?

A couple of more details: right when I first test drove the car after the mods, the ABS was engaging whenever I braked. He fixed it but unsure if that hints at some wiring issue. Also, if I ease into the throttle, it honestly feels more responsive than if I go WOT (only at the lower rpms).

Sponsored

 

[BmacIL]

Well you can see a decent torque dip between 3k-4.5k on your dyno charts. I'd say it's probably the tune, though the GT350 manifold does have some lower end torque loss, but by that point you're starting to get into the midrange where it is very similar to the stock manifold.

 

[DarkestHour]

Did you log these dyno runs? Post up the log.

 

[aleccesarenriquez]

Having a hard time with the sct drivers. The drivers that install automatically seem to be corrupted. Even when I delete them, download them manually, and then use the new ones, it goes back to the previous error.

Anyways i can ask my tuner to send me the logs though when I see him this Thursday.

Bmac: I agree, I do see a little torque loss in that range but since the overall curve is shifted higher, why would it feel worse than stock?

 

[Sean@LethalPerformance]

Yeah, best move from here would be to get with your tuner so he can take a look at some data-logs. The TQ loss should shouldn't be as bad since your using the harness instead of locking out the IMRC's for the 18 manifold.

 

[66sprint6]

Are you throwing any codes...perhaps a P2006 or P2007? Mine was the same way. It made wicked good power but then the IMRCs would close and stay closed and it made the car feel like a bone stock 5.0 Foxbody. It would pull thru the RPM no problem but with no power at all. I would either restart the car or clear the code if a CEL popped up and it would go away for a while.

Matt

 

[aleccesarenriquez]

Nope no codes yet, although our issues do sound similar. Have had it on for about 800-1000 miles now.

Oddly enough the tuner has looked at it and said maybe it’s a throttle response issue and that he can address that but I’m not sure that’s what’s going on. This morning on my way to work I was messing around it has absolutely no problem picking up when I squeeze the throttle, but when I go wide open, it’s like it’s stuck

 

[66sprint6]

Next time it pulls like that, clutch in, turn the car off and then restart it real quick while rolling. Then hit it and see if it doesnt scream! If so, you have an issue with your wiring. Are you running the plug and play harness or is the IMRC wiring soldered to the factory wiring?

Matt

 

[aleccesarenriquez]

Plug n play.

I can give what you suggested a shot on the way home

 

[66sprint6]

Ok, the plug and play harnesses are AWESOME quality BUT the car itself, whether its the sensors on the intake or the factory wiring is appearing to be very picky and will work for a bit and then will close the IMRCs and keep them closed. I have that issue on the drivers side only and have been working on getting it sorted out. Try what I said and if it pulls like a freight train then you will need to either

1) solder the PNP harness to the factory harness

or

2) Find some of the Ford pigtails and solder them in.

On my car it seems that the sensor on the intake is whats being picky and it only likes the Ford pigtail with Ford plug. The passenger side sensor likes the PNP harness just fine LOL

Matt

 

[aleccesarenriquez]

I’ll give this info to my tuner. He didn’t really believe me that anything was wrong when I showed him because it happened to be pullin fine when I showed him lol.

This would explain a lot though.

Now that I think about it, both times I’ve tried to show someone what was wrong, they got in the car and it pulled just fine. One common factor though, I had turned off the car before I showed them. Why would power cycling cause the problem to go away?

 

[66sprint6]

Yep. Mine would pull nice for a couple pulls then it would happen and keep happening till I shut the car down and started it back up. Did it at the track, I just restarted and made 3 more runs. It didnt do it on the dyno for me either the next weekend but did on the way home. I restarted it while rolling so I could have a little fun and it went away for a bit.

Matt

 

[1badrz28]

Have your tuner add some timing in the low rpms. It will take a lot of the bounce away during the throttle tip in. I had both PBD and Lund do that, and the car accelerates and responds a lot better at the low rpms.

 

[GTBOB]

You need to have the cam timing optimized for the different volumetric efficiencies of the intake manifold.

 

[aleccesarenriquez]

You need to have the cam timing optimized for the different volumetric efficiencies of the intake manifold.

Is this not something he would’ve taken care of during the tune after the install?

Sponsored