installation is complete, weird WOT feeling

[BH Tuner]

Hey Guys,

so finally, i installed my Roush TVS blower, ran into some small problems, like the tune file i was using was corrupted, and when i used a different strategy some paramaters were missing and SCT were super helpful to help me get it fixed.

so finally i started the car and it feels amazing, took her for a drive around, and i noticed a couple of things, the RPM feels heavy and on WOT it felt like i had turbo lag the RPM was heavy and once i reached around 4.5k rpm the rpm was faster. the good thing the car is responding to my commanded lambda 0.79 with no knock at all.

what could cause this weird heavy rpm response and the weird lag feeling? i was thinking a couple of things
- belt slip ( the car jumped to 15PSI when the RPM was heavy and when it dropped to 11Psi it felt like a different animal )
- VCT settings ( i'm using roush strategy with no changes to the VCT settings at all )
- spark ( the test run i had i had the universal spark pulled from all the tables by -4)
- bosst leak

the car got the following mods:
- Ported 2.3 roush blower
- VMP 67mm throttle body
- JLT CF 127mm intake
- MMR cooling Mod
- Dual Heat Exchanger
- FIC 1000cc Injectors
- American Racing Headers & Xpipe with no Cats
- Stock pulleys

 

[Riddick]

What size upper pulley are you running? If your seeing 15 psi on a ported blower you are spinning it way to fast. I wouldn't go any smaller than a 79mm on stock bottom end especially if your on pump 93 fuel. A 79mm should net around 10-11 psi on a ported blower.

If you have belt slip there should be belt dust near your upper pulley.

 

[BH Tuner]

What size upper pulley are you running? If your seeing 15 psi on a ported blower you are spinning it way to fast. I wouldn't go any smaller than a 79mm on stock bottom end especially if your on pump 93 fuel. A 79mm should net around 10-11 psi on a ported blower.

If you have belt slip there should be belt dust near your upper pulley.

the upper pulley is the stock pulley, my doubt is that my Boost gauge was reading wrong.

i just took the car for a long drive, the jerking is still there and my gas pedal feels so heavy especially between the 2k to 4k rpm. I'm not sure if it's my Throttle although i'm sure my values should be fine especially that i crossed the values against several different tunes and they are all the same.

one thing i have in doubt is the strategy, i had to make some adjustments on the axle ratio and the axle switch was on, when i switch it off the tune won't load and it will ask me to return the car to stock.

 

[Riddick]

Roush offers numerous pulley sizes. Their stage 3 blower kit comes with a 80mm and I think their base kits run an 85mm or maybe even larger pulley. Also, VMP makes tons of pulley sizes, you should be able to look at the pulley and it will be stamped with what size it is. Considering the blower was ported and you probably bought it used someone probably had a different pulley on it.

You mentioned you are going off the Roush strategy, did you adjust for the VMP throttle body? The roush kits come with a Twin 60 and your running a Twin 67. Also, the Roush intakes are 110mm and yours is 127mm. Make sure your tune is right, definitely sounds like something is off.

 

[BH Tuner]

Roush offers numerous pulley sizes. Their stage 3 blower kit comes with a 80mm and I think their base kits run an 85mm or maybe even larger pulley. Also, VMP makes tons of pulley sizes, you should be able to look at the pulley and it will be stamped with what size it is. Considering the blower was ported and you probably bought it used someone probably had a different pulley on it.

You mentioned you are going off the Roush strategy, did you adjust for the VMP throttle body? The roush kits come with a Twin 60 and your running a Twin 67. Also, the Roush intakes are 110mm and yours is 127mm. Make sure your tune is right, definitely sounds like something is off.

i will check the pulley later on tonight. because when i first got the kit it had a much smaller pulley (69mm) and this is supposed to be the stock pulley (the previous owner was running 19PSI and i still have like 4 different pulleys not installed)

i did make the adjustments for the throttle body and i did also made the changes for the 127mm JLT intake.

i just rewrote a new tune based on my original strategy and i'm really hoping it works out, i'll give it a test in a couple of minutes.

 

[68gtscode]

I would post this in Tuning A La Cart section. I think you would get more traffic from knowledgeable people.

 

[BH Tuner]

I would post this in Tuning A La Cart section. I think you would get more traffic from knowledgeable people.

that i will do perhaps.

so the update is my car won't accept the rewritten file i made yesterday, but my guess is that my effective throttle area is what causing the issues. so i worked that problem out and will give it a go.


UPDATE to REDDICK

the pulley is 79mm

 

[BH Tuner]

attaching a video of the issue I'm having.

 

[BH Tuner]

well to update anyone who might have the issue.

problem is resolved, throttle is opening up perfectly. just had to do a ton of datalogs and work on the effective throttle area and it's all done.

car is very responsive and even at 50% to 70% pedal it pulls so hard. what is left is to complete my testing and spark tables and an oil change and i'm all set for the dyno.

 

[nyuk98GT]

Good detective work to solve the problem, BH Tuner! Thanks for the updates - it's nice to hear about the follow-up work and successful resolution. Please post up your dyno run graph so we can cheer you on! Any engine bay photos?

Keep up the good work.

Chris

 

[BH Tuner]

Good detective work to solve the problem, BH Tuner! Thanks for the updates - it's nice to hear about the follow-up work and successful resolution. Please post up your dyno run graph so we can cheer you on! Any engine bay photos?

Keep up the good work.

Chris

i always love to share because i know one day someone will be in my spot and i might be the one who gives the solution .

no dyno yet, i'm taking it very slow i dunno why i'm not even excited for the dyno, maybe because i'm tuning it on my own, but will definitely share the numbers.

the engine bay is super dirty lol, i'll post the photos of the whole build once i'm done