Cars acting up sense double pumper install

[Onalky87]

I have not gone Wot yet this year. But easing into the throttle(30-40%) the car stumbles and noses over for a split second then picks back up. Happens coming into boost (0-10psi). I wanna pin point it to a fuel issue sense that's the only difference sense last year. The fp regulator that I currently have is a Bosch 0 280 160 233 which I believe is not adjustable. My a/f when it spools is 14-15:1 and fp is 37ish with line connected

 

[Chuck Leeper]

Double pumper and no adj reg?? That would be the FIRST item to correct. [Especially, if the mods in the signature are what's on the car!]
Any data info, from Scanmaster, powerlogger??
It may well be that the DP in-tank connection are leaking, 1 pump is not turning on, etc.
14-15 AFR is going to get into problems, really fast, should you continue.
At this point, a membership in the DOTC club is a possibility!

 

[Onalky87]

Ya it looks like I'm going to have to buy an adjustable reg and add base fp. I just wasn't expecting a fp change to change all this. I had no issues with car when I had walbro 340

 

[Mike T]

Ya it looks like I'm going to have to buy an adjustable reg and add base fp. I just wasn't expecting a fp change to change all this. I had no issues with car when I had walbro 340

Just got a look at your signature, 590 whp would be like 750 at the crank. Was that on the 340 ? Short time of 1.90, lifting after the 1/8, 11.40 et, that car has to be close to low 10 high 9. The regulator is a must at your level and good job on the build sounds like the regulator & fp were the only thing's left out.

 

[bison]

Just got a look at your signature, 590 whp would be like 750 at the crank. Was that on the 340 ? Short time of 1.90, lifting after the 1/8, 11.40 et, that car has to be close to low 10 high 9. The regulator is a must at your level and good job on the build sounds like the regulator & fp were the only thing's left out.

It was more like 10.40-10.50 power in the 590whp tune with a 1.48-1.5 sixty time

 

[Mike T]

It was more like 10.40-10.50 power in the 590whp tune with a 1.48-1.5 sixty time

Was that an actual pass or estimate ?

 

[Onalky87]

Was that an actual pass or estimate ?

An estimate Car is prob a 10.4 car with a full pass. That 11.40 run was the first time ever going down the track. And was having some issues. I looked down and say 19* KR haha so that's y I rolled out the back half

 

[bison]

Was that an actual pass or estimate ?

It's a very close estimate based on many similar combos that made very similar power.

 

[Mike T]

It's a very close estimate based on many similar combos that made very similar power.

Except for the 60#er's Looks like he has all the parts in place for that sub 10 second run.

 

[Onalky87]

Except for the 60#er's Looks like he has all the parts in place for that sub 10 second run.

It would be nice. However IIRC I think he told me before that my turbo would be running out of steam

But there's nothing I want more then a 9.99 pass

 

[bison]

Except for the 60#er's Looks like he has all the parts in place for that sub 10 second run.

If he wanted to run 116+ octane and run the boost into the 32-33 range and didn't have any fuel delivery issues it will make enough power to support those times potentially but going from 10.40 to 9.90 is a huge jump and it doesnt come easy.

 

[Onalky87]

If he wanted to run 116+ octane and run the boost into the 32-33 range and didn't have any fuel delivery issues it will make enough power to support those times potentially but going from 10.40 to 9.90 is a huge jump and it doesnt come easy.

I say we throw ur slicks on it and u in the drivers seat and give her hell haha

 

[Mike T]

It would be nice. However IIRC I think he told me before that my turbo would be running out of steam

But there's nothing I want more then a 9.99 pass

We have a local car here in central Florida that had a older 67 on it with less in the motor than you have crack the nines. I think it now has a 76 and some internal changes going 9.30s, the man that tunes it is amazingly talented and his wife drives the car.

 

[Mike T]

If he wanted to run 116+ octane and run the boost into the 32-33 range and didn't have any fuel delivery issues it will make enough power to support those times potentially but going from 10.40 to 9.90 is a huge jump and it doesnt come easy.

Would the 32-33 be due to the 67 ? On a side note because some of the higher power stuff is new to me the former owner of my GTQ 70 said he won BG a few years ago with a 9.60 at 24psi. Does the GTQ 70 out flow the 67 by that much?

 

[Onalky87]

Would the 32-33 be due to the 67 ? On a side note because some of the higher power stuff is new to me the former owner of my GTQ 70 said he won BG a few years ago with a 9.60 at 24psi. Does the GTQ 70 out flow the 67 by that much?

Was it a 4 bolt turbo? Mine is a 3 bolt

 

[Mike T]

Was it a 4 bolt turbo? Mine is a 3 bolt

The 70 is a 3 bolt with an 85 housing & I run it on the street every day.

 

[bison]

Would the 32-33 be due to the 67 ? On a side note because some of the higher power stuff is new to me the former owner of my GTQ 70 said he won BG a few years ago with a 9.60 at 24psi. Does the GTQ 70 out flow the 67 by that much?

Im basing that pressure on last results. It miht not even make that muck boost if the air was crappy. The 6776 has been 9.80's. Going 9.6 on a stock stroke 9:1 engine@25psi is not common especially if done with any of the smallish hyd cams that guys typically run. If it had a real fast ramp cam and the pressures were adequate then an engine with a set of aluminum race ported heads sees a huge advantage with larger turbos. I recently did a turbo change on a members car here from a 45a or t64e (or whatever vendors feel like calling it) to a 70hpq and the car ran faster than it ever did with 2psi less boost and 1 degree less timing. The 45a uses a 66mm inducer with a clipped 76p ex wheel. Re-dialing that 2psi back in is going to really wake it up. The difference in rwhp between the 2 was about 40-50hp if I recall correctly and this was an alky 93 tune. If he had adequate fuel system I'd expect over 100whp difference at 31-32psi. That's a lot from just a turbo change but his engine is up to the task if his fuel system can support it. Fred would be working everything very hard to run those numbers with any turbo. He has a much less aggressive valvetrain setup, heads that flow less, and a lower CR. I repaired the shortblock on his car last year. I installed the heads/cam exactly how they were removed prior. I didn't analyze anything on the top end. I know there's room for improvement there. There is with just any cast cam setup. The lobes just flatten out a lot more when ground on the cast Buick cam cores. More cam/spring/turbo will net a bunch of power up top. Bsfc improves quite a bit when dropping backpressure too. Mostly due to pumping losses being reduced.

 

[Onalky87]

Im basing that pressure on last results. It miht not even make that muck boost if the air was crappy. The 6776 has been 9.80's. Going 9.6 on a stock stroke 9:1 engine@25psi is not common especially if done with any of the smallish hyd cams that guys typically run. If it had a real fast ramp cam and the pressures were adequate then an engine with a set of aluminum race ported heads sees a huge advantage with larger turbos. I recently did a turbo change on a members car here from a 45a or t64e (or whatever vendors feel like calling it) to a 70hpq and the car ran faster than it ever did with 2psi less boost and 1 degree less timing. The 45a uses a 66mm inducer with a clipped 76p ex wheel. Re-dialing that 2psi back in is going to really wake it up. The difference in rwhp between the 2 was about 40-50hp if I recall correctly and this was an alky 93 tune. If he had adequate fuel system I'd expect over 100whp difference at 31-32psi. That's a lot from just a turbo change but his engine is up to the task if his fuel system can support it. Fred would be working everything very hard to run those numbers with any turbo. He has a much less aggressive valvetrain setup, heads that flow less, and a lower CR. I repaired the shortblock on his car last year. I installed the heads/cam exactly how they were removed prior. I didn't analyze anything on the top end. I know there's room for improvement there. There is with just any cast cam setup. The lobes just flatten out a lot more when ground on the cast Buick cam cores. More cam/spring/turbo will net a bunch of power up top. Bsfc improves quite a bit when dropping backpressure too. Mostly due to pumping losses being reduced.

I would be working everything very hard to run what numbers?

 

[3.8L V-8 eater]

Onalky87,
Be sure to update this thread when you get this problem resolved...I may be having a pump going bad and my issues are similiar to yours....Think I'm just going to change the pump seeing it has been in since I bought the car...

 

[Mike T]

Im basing that pressure on last results. It miht not even make that muck boost if the air was crappy. The 6776 has been 9.80's. Going 9.6 on a stock stroke 9:1 engine@25psi is not common especially if done with any of the smallish hyd cams that guys typically run. If it had a real fast ramp cam and the pressures were adequate then an engine with a set of aluminum race ported heads sees a huge advantage with larger turbos. I recently did a turbo change on a members car here from a 45a or t64e (or whatever vendors feel like calling it) to a 70hpq and the car ran faster than it ever did with 2psi less boost and 1 degree less timing. The 45a uses a 66mm inducer with a clipped 76p ex wheel. Re-dialing that 2psi back in is going to really wake it up. The difference in rwhp between the 2 was about 40-50hp if I recall correctly and this was an alky 93 tune. If he had adequate fuel system I'd expect over 100whp difference at 31-32psi. That's a lot from just a turbo change but his engine is up to the task if his fuel system can support it. Fred would be working everything very hard to run those numbers with any turbo. He has a much less aggressive valvetrain setup, heads that flow less, and a lower CR. I repaired the shortblock on his car last year. I installed the heads/cam exactly how they were removed prior. I didn't analyze anything on the top end. I know there's room for improvement there. There is with just any cast cam setup. The lobes just flatten out a lot more when ground on the cast Buick cam cores. More cam/spring/turbo will net a bunch of power up top. Bsfc improves quite a bit when dropping backpressure too. Mostly due to pumping losses being reduced.

The 9.60 run was on Champion iron heads and you are right about the stroke he had a 3.625 Cat. My car is a stock stroke, mild ported 8445 heads w/large valves, 204/214 and I run the 70 @ 20#s. Would you have a guess on hp ?