CeBrwn5454

iTrader: (2)

Greetings,

I've got a problem with my vortech blower, or so I think, and need some help/advice before I send it off to 928 Motorsports for a rebuild. The blower is a V2 SQ-Trim on my 04 G35 Coupe AT with full bolt ons (headers, test pipes, exhaust, plenum ect...).

The facts:
UR Underdrive crank pulley + 2.87 pulley ='s 6.5 lbs of boost.
Stock crank pulley + 3.12 pulley ='s 3.8 lbs of boost.

BOTH of the above netted 355 rwhp hot runs...375rwhp on cold runs, but the stock crank pulley set-up torque was greater than the underdrive crank pulley by 20 ft/lbs.

Also, the blower is surging at idle. Jared, the head tuner at UpRev, pulled the throttle input and it is flat, yet the MAF voltage is all over the place. The surge causes the car to sound like it is cammed (idle raising and lowering at 50-100RPM intervals). The surge at idle is also causing my A/F's to range from 13.4-16.6.

I am not making up the numbers, my car was on the dyno at UpRev in Austin. Please do not say it is an inaccurate boost reading...Jared used both his boost gauge (Osiris software) and stand-alone gauge, both read the same thing.

I have performed a boost leak test and replaced the BPV. (Rule those out)

I appreciate any input.

Thanks in advance.

binder

iTrader: (8)

so why couldn't the tuner who has experience with these cars fix it when it was on the dyno?

are you using a reflash?

Mine is bouncing like that but it always has since my vortech. It seems to be worse now but not by much. I'm running the ss box and stock ecu. I'm pretty sure mine is a problem with the closed loop fuel management of the ecu. a reflash should be what will fix this.

also, the stock crank along with a 3.12 pulley should yield well over 3.8 psi. The 3.33 pulley should give around 9psi (give or take). 3psi is really low so i would say boost leak somewhere.

str8dum1

iTrader: (11)

the blower cannot surge. its connected to the motor. your motor is surging.

theres probably nothing wrong with your blower. if there was it would be grinding or leaking oil.

and if it was the blower, you can take off teh cog belt and have a perfectly running car????

you have EMS problems if your maf is all over the place, that might have went bad.

How did you perform a boost leak, please dont say you sprayed pipes with soapy water and looked/listened

CeBrwn5454

iTrader: (2)

Jared has dyno tuned the car multiple times...so if you call that a reflash, sure (stock ECU, yes). I am not running an SS Box...for fuel I've got 600cc DW injectors, and a Walbro.

The boost leak test was done with a cap on the in-pipe to the blower with a open/close valve and an air tank...it was done properly. When the boost leak test was performed we did find one leak, fixed it, and then the system held 5 mins at 20 lbs.

I am well aware of the amount of boost that each pulley should yield...thus my question as to what is wrong.

Agreed that the blower cannot surge, yet it is forcing differing amounts of air into the engine which is causing the surge.

...I'm not a noob.

Thanks for the quick answers.

str8dum1

iTrader: (11)

ya so your motor must run just fine with the cog belt off right?

if it doesnt, its not the blower. easy 10 second test

CeBrwn5454

iTrader: (2)

I will check that asap...but I have run it in the past without the cog belt and the motor is just fine.

My problem is that I have never been able to achieve normal boost numbers whether with the 2.87 pulley or the 3.12. I have been to UpRev 4 times now each time with a different set-up, yet always yielding low boost with overall good dyno results.

Jared and I had a hard time blaming anything on the motor when we are getting great numbers considering the amount of boost.

Thoughts?

If everything runs fine with the cog belt off, then what do you recommend?

OldManZ350

iTrader: (23)

If that is an accurate Boost Reading, then you have major Belt Slippage.
(Hard for me to beleive that you made 375whp@ 6.5 lbs of Boost)
I only made 394whp@10lbs of boost cold

As for the surging problem, your tune is out of range in closed loop and Jared should know that.

Please list your setup in detail.

What is the Mean Dia of your aftermarket pulley? A smaller Dia will create more problems with belt slip


Tim

CeBrwn5454

iTrader: (2)

The dyno graph does not show any belt slip. (No waves of power) It is actually very smooth, the only difference being that boost comes on sooner with the stock crank pulley and 3.12 set-up than the UR Underdrive crank pulley and 2.87 set-up. The belt does not squeal at start up or anything...its tight.

My set up:
Headers, test pipes, exhaust, crawford plenum, one step colder plugs, gtm pulley mod, walbo pump, 600cc DW injectors, AAM oil pan spacer, tranny cooler, oil cooler, greddy catch can, Osiris software. (Thats all of I can think of that has to do with the engine/blower)

I do not know the diameter of the UR crank pulley. I will look for it later today, but my guess is that the blower should be spinning at somewhat comprable speeds between the two set-ups.

Stock crank pulley w/ 3.12 v. UR Underdrive crank pulley (smaller than stock) w/ 2.87 pulley.

OldManZ350

iTrader: (23)

1. Can you post your Dyno?

2. I need a number to calculate. And if you think that they are comparable, than WHY would one pulley setup 6.5 lbs and the other 3.8 lbs.

djamps

iTrader: (1)

The idle 'surge' is the stock ECU struggling with the larger injectors in closed loop mode and low duty cycle. A fuel return and some careful scaling (possible the opposite direction you think) should help smooth it out.

binder

iTrader: (8)

i'm just throwing this out there and not attacking you in any way.

The boost numbers are odd for a system that holds pressure. They are definitely not typical numbers for that setup and hp number.

600cc injectors are known to have idle issues when not tuned properly for their size. The uprev flash should fix that and I would assume Jerod is a knowledgable person to have that adjusted properly.

With boost holding like it is on the test, i would almost have to say it's 100% the boost gauge that isn't properly reading.

This is a very interesting issue since you have a qualified tuner working with you and there are still issues.

whoojong

iTrader: (9)

Sounds like a vaccuum leak to me for the surging from 50 to 1000 rpm.

As for the AF, did you do the walbro regulator mod? Maybe your Fuel pressure is not staying constant.

http://www.cj-motorsports.com/342install.htm

CeBrwn5454

iTrader: (2)

Yes I did the Walbro regulator mod.

I contacted Jared an hour or ago and should have the dyno graphs later today. I also refered him to this thread so maybe he or Richard will chime in to help explain the situation.

Still looking for the diameter of the underdrive crank pulley...

Thanks for everyones input!

CeBrwn5454

iTrader: (2)

Dyno graph is below.

Just spoke with Jared...he advised that I also unhook the line from my plenum that goes to the BPV and blow through it to make sure it is not restricted in any way. We have been reading the boost by splitting the out-of-the-plenum line to go to the BPV as well as read boost.

I was not spot on with the numbers as you can see below, but realize that that the blue was not the best run of the day (it was a hot run), it was just most indicative of the boost v. hp relation.

Thoughts?

CeBrwn5454

iTrader: (2)

binder

iTrader: (8)

that would be ruled out with the pressure test that showed up fine.


looking at those numbers, it appears that the boost is half of what it should be. Is there any way that it is set to read half? 5.96 would put you almost 12psi at redline which is standard for a 2.87 pulley on our cars (give or take a little for variations)

CeBrwn5454

iTrader: (2)

Jared's response:

"Nope. It's actually just reading the voltage of the sensor. The sensor has a V per pound output."

PunKidd

I don't know why I didn't think to check the fuel pressure while it was on the dyno. That's been a problem with these Walbro pumps on many occasions. More often than not there is a leak from a botched installation and we loose pressure at high RPM. This one is doing fine at the top end, but I didn't even think to check if it's stable at idle.

I'd still like to hear back about the port in the plenum, if that has some blockage it would explain the bad boost readings (with two gauges) and could even explain the unstable idle if the BOV is getting bad pressure that is keeping it unstable.

Still interested in any other ideas though. We've been chasing our tail on this one for a while now.

Jared@UpRev.com

06g35meister

iTrader: (3)

Watching Christian going through all of this, i am equally as stunned as anyone else here, but know that Christian has troubleshooted everything that could be wrong with the system. I said the boost was too low for the power, but they had 2 gauges reading identical numbers... The only thing i can think of at the moment is there might be a clog in the manifold line...

My lack of knowledge in the department is my shortcoming here, but it would seem the surging would come from something like fincannons supra, the car sprays fuel in, revs up, then cuts fuel at the higher rpm and drops, fincannons has this rev problem as well, maybe once you get yours fixed it will be the same on fincannons.

Your boost numbers are insanely low for the setups though.

Oh and +1 for Uprev, great guys helping Christian out!

PunKidd

And I don't believe the injectors are the cause of the bad idle. I've tuned a 600WHP G35 with built motor and JWT TT kit that was running 1000cc injectors and we had a nice flat idle at 700RPM. What we're seeing here are BIG surges in air flow when the throttle plate and injector pulse widths are not moving whatsoever. If the BOV is getting a bad pressure reading and becoming unstable, that would explain it.