So here's the deal, I have been fighting a shift hesitation for some time now. No its not the PPRV. Those of you that are running 11.50's or faster with returnless fuel system. I would like to take a look at your data logs if you have them.
11.50's and faster with returless fuel system
- Thread starter r103
- Start date
I dont have any logs for you but what pumps you running? I was running low 10's with a returnless setup for a while and never had any issues. Twin gt pumps BAP -8 line to stock rails and 60's.
Stock pumps. It was hesitating after shift with stock blower too. It doesn't do it all of the time but it does it enough to really piss me off! It seems like the faster I shift the more likley it is to do it. On the dyno everything looks perfect... the problem is when shifting the FP spikes then drops so when I'm back in the the throttle there's not enough fuel.
I have no problems! I have GT (Supercar) pumps, BAP & PPRV delete with my E85 setup and POSI Ported Eaton .... maybe you need more pump?! Whens the last time the fuel filter was changed?
No issues here. Basically the same as above.
Sounds like it may be in the tune.
i'm a tad short of the 11.50 goal but i have no issues. i still have the pprv even as my only fuel mods are a bap. next time at the track (oct 7th) i'll be datalogging my runs to try and figure out why my car stalls after each pass so if you need something by then i'll be happy to share them with you.
I run mid 10s and have the hesitation on occasion. My belief is it is the fuel pressure fluctuation from letting off to shift.
I've noticed that if I shift rather quickly and only let off the throttle half way it will not hesitate.
I run 3 gt pumps in a fore hat, 3 fpdm's, -8 line, fore rails, 80s.
I've noticed that if I shift rather quickly and only let off the throttle half way it will not hesitate.
I run 3 gt pumps in a fore hat, 3 fpdm's, -8 line, fore rails, 80s.
What he said. Drag racing i never have the hesitation, open tracking it happens all the time because i do let off the gas all the way for the braking zones. Power shifting it never does it.
What is your fuel level? I ran 10.5's last yr with returnless. Everything in tank was stock at time with a BAP. I found that if i ran tank down around 1/2 tank i would get shift hesitation. If tank was 3/4 it never had an issue. Just a thought.
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Thats whats crazy about my car I can no lift shift and it is more likely to do it.
It has done it with anywhere from 1/4 to 3/4 tank.
i only noticed if i shifted too slow...im still returnless..but going auto now lol.
I had the same problem, went return and the issue was gone. However, after speaking to another shop owner/tuner he said it's in the tune. There's a small lean spot causing the problem and he mentioned the MAF tables so I'd focus there first.
After melting my motor LEANED out
The shop that built the car ( before i bought it )
Had GT pumps with single stock FPDM and pprv delete and it had hesitation
New motor new tune fore hat dual fpdms
Problem gone
Did it always do it?
The shop that built the car ( before i bought it )
Had GT pumps with single stock FPDM and pprv delete and it had hesitation
New motor new tune fore hat dual fpdms
Problem gone
Did it always do it?
After melting my motor LEANED out
The shop that built the car ( before i bought it )
Had GT pumps with single stock FPDM and pprv delete and it had hesitation
New motor new tune fore hat dual fpdms
Problem gone
Did it always do it?
The shop that built the car ( before i bought it )
Had GT pumps with single stock FPDM and pprv delete and it had hesitation
New motor new tune fore hat dual fpdms
Problem gone
Did it always do it?
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