Have a 168 pulley and OE tune, put Kleemans mid length (1st cats removed test pipe in place) on my car no other mods. Went from 487 to 493 and 550tq stayed the same. I think the 168 may have reached its limit
here is the data only 8.6 lbs of boost. at 6233 rpm
datetime","Air Intake Temp","Timing Advance","Intake Manifold Pressure","RPM","Boost"
2011-10-26 16:30:53.367,120.2,-21,23.35108,6233,8.655128

And the highest boost reading was 10.3 lbs.
2011-10-26 16:30:52.487,100.4,-19,25.09153,4546,10.39558
All the data through the run

"datetime","Air Intake Temp","Timing Advance","Intake Manifold Pressure","RPM","Boost"
2011-10-26 16:30: 22.809,91.4 ,-5.5, 6.526699, 596,- 8.16925
2011-10-26 16:30:23.702,91.4,-6,6.381661,597,-8.314288
2011-10-26 16:30:24.602,91.4,-9,6.381661,582,-8.314288
2011-10-26 16:30:25.507,91.4,-7.5,6.381661,578,-8.314288
2011-10-26 16:30:26.406,91.4,-18,5.656472,717,-9.039477
2011-10-26 16:30:27.315,91.4,-18,5.221359,846,-9.47459
2011-10-26 16:30:28.234,91.4,-18,4.786245,979,-9.909703
2011-10-26 16:30:29.132,91.4,-19,4.49617,1029,-10.19978
2011-10-26 16:30:30.020,91.4,-19.5,4.786245,1062,-9.909703
2011-10-26 16:30:30.928,91.4,-23.5,5.221359,1185,-9.47459
2011-10-26 16:30:31.818,91.4,-27,5.076321,1414,-9.619628
2011-10-26 16:30:32.716,91.4,-28.5,5.076321,1658,-9.619628
2011-10-26 16:30:33.619,91.4,-30,5.221359,1928,-9.47459
2011-10-26 16:30:34.512,91.4,-31,4.786245,2216,-9.909703
2011-10-26 16:30:35.410,91.4,-31.5,4.786245,2457,-9.909703
2011-10-26 16:30:36.309,91.4,-30,5.511434,2262,-9.184515
2011-10-26 16:30:37.189,91.4,-29.5,5.946548,1881,-8.749401
2011-10-26 16:30:38.099,91.4,-29.5,5.656472,2064,-9.039477
2011-10-26 16:30:39.005,91.4,-30,5.511434,2236,-9.184515
2011-10-26 16:30:39.893,91.4,-31,5.656472,2395,-9.039477
2011-10-26 16:30:40.772,91.4,-31,5.511434,2555,-9.184515
2011-10-26 16:30:41.681,91.4,-31.5,5.511434,2672,-9.184515
2011-10-26 16:30:44.072,91.4,-28.5,6.671736,2086,-8.024213
2011-10-26 16:30:44.972,91.4,-28.5,6.381661,2072,-8.314288
2011-10-26 16:30:45.871,91.4,-28.5,6.671736,2168,-8.024213
2011-10-26 16:30:46.778,91.4,-29.5,6.526699,2270,-8.16925
2011-10-26 16:30:47.705,91.4,-29.5,6.526699,2366,-8.16925
2011-10-26 16:30:48.594,91.4,-29.5,6.816774,2449,-7.879175
2011-10-26 16:30:49.493,93.2,-10,24.80145,2680,10.1055
2011-10-26 16:30:50.392,96.8,-14.5,24.36634,3672,9.670392
2011-10-26 16:30:52.487,100.4,-19,25.09153,4546,10.39558 <max boost
2011-10-26 16:30:53.367,120.2,-21,23.35108,6233,8.655128 <max rpm
2011-10-26 16:30:54.270,122,-18,25.38161,5043,10.68566
2011-10-26 16:30:55.168,120.2,-31,3.045793,4641,-11.65016
2011-10-26 16:30:56.067,116.6,-31,3.045793,4388,-11.65016
2011-10-26 16:30:56.955,114.8,-30,2.900755,4047,-11.79519
2011-10-26 16:30:57.863,113,-29.5,2.900755,3708,-11.79519
2011-10-26 16:30:58.740,111.2,-28,2.900755,3362,-11.79519
2011-10-26 16:30:59.671,109.4,-26.5,3.045793,3032,-11.65016
2011-10-26 16:31:00.920,109.4,-25,2.900755,2684,-11.79519
2011-10-26 16:31:01.828,107.6,-23.5,2.900755,2212,-11.79519
2011-10-26 16:31:02.717,107.6,-22,3.045793,1881,-11.65016
2011-10-26 16:31:03.624,107.6,-19,3.335868,1567,-11.36008
2011-10-26 16:31:04.556,107.6,-2.5,3.770981,1179,-10.92497
2011-10-26 16:31:05.479,107.6,-9,4.786245,907,-9.909703
2011-10-26 16:31:06.371,107.6,-4,5.656472,714,-9.039477
2011-10-26 16:31:07.268,107.6,-4.5,6.381661,696,-8.314288
2011-10-26 16:31:09.465,105.8,-2.5,6.671736,631,-8.024213
2011-10-26 16:31:10.763,105.8,-3,6.381661,619,-8.314288
2011-10-26 16:31:11.671,105.8,-6,6.381661,605,-8.314288
2011-10-26 16:31:12.580,105.8,-7,6.381661,594,-8.314288
2011-10-26 16:31:13.477,105.8,-7,6.236623,587,-8.459326

 

I'm no expert in interpretation of the data but love your updated signature.

 

you are at the limits of your intake also,get a 82mm tb,renntech airbox and retune and you should hit 515-520whp

ps let me know when you go bigger pulley,im looking to go to a 168 setup and I will dyno that vs my 178 pulley.

 

The way you posted it is confusing as hell, but I see 11.8psi quite a few times. Maybe I'm just confused. Can you maybe post it up as an image file or something so that the table looks normal?

 

I'd ask Shardul. If he doesn't know the answer he knows who does.

 

I know it is but, thats the way the file opens. Your seeing a spike in boost (11lb) because the run was completed and the throttle was let off.

This is my dilemma...
How am I getting 10.39558 boost at 4546rpm and only 8.6lb at 6223rpm. I would think since the motor is spinning at a higher rpm the blower would create more boost.

Is it that the motor runs more efficient at a higher RPM and its maxing out the 168 pulley or is the car bleeding off boost?

If Shardul was here im sure he would chime in and I would make a choice of what to do and the paying sponsors on here would see some business from my end.

Thanks Scratch. I need to be sure of whats going on before I make the next move.

 

I went from 502whp to 530whp from just adding a ported 80mm tb and not even touching the tuning.

I have same mods as you with the addition of a renntech airbox tb.next time you dyno take the whole intak off with no filters and see if theres more in her.

you lost boost because its flowing more threw the engine and its showing less boost but there is more power to be made with tb and airbox.

 

@Scratch
The dyno #s you mentioned, are they with the 178 or 168?

Wouldnt a larger TB and AB just make the problem worse as far as boost #s (filling a bigger hole)? If the pulley is too small then thats my next step. I would like to do a single upgrade at a time and dyno for results so I can see how much of a benefit each upgrade made.

 

Centrifugal superchargers build boost exponentially because of their design, but screw type superchargers don't so it's not uncommon to see the same boost throughout the rpm range or even a loss of boost in the upper rpms.

Here is a previous scan I made of my car:


This is 2nd and 3rd gear. You can see that at in the 4000ish rpm in 3rd my car sees 14+psi yet at 6000 in 2nd it actually touches 12.9psi. Even at 5,600 in 3rd it goes down to 13.2.

Keep in mind I have a 178mm Pulley.

I do agree that the possibility exist that opening up your throttle body and intake setup should mostly solve this issue ( in my car as well, I have stock TB and airbox ).

 

Incorrect, freeing up restriction in the inlet of the supercharger will make the supercharger more efficient. Remember, air isn't being forced into the throttle body, it's being sucked into the throttle body. It's vacuum that it sees, not boost.

 

I got you GT, its sucking through the throttle body (restriction) and the blower is filling the intake. Gezus man...Im down nearly 5lb of boost compared to your numbers. I think TB is my next upgrade since I have no cooling mods and live in a warm climate.

 

Remember though, my pulley is a good size larger than yours.

 

Always good...having a bigger pulley. Looks like my car has the 74mm TB(113 141 01 25) disappointing to find since mine is an early 03 model.

GT since your setup is similar what would you go with, the pulley or TB in my case?

 

I used to not believe to much in the larger TB business but after careful consideration and seeing some decent numbers being put down with larger TB's I am beginning to think that perhaps a large TB will be better than a larger pulley. If you had the oem pulley I would say get the larger pulley, but since you already have a larger pulley then just stay with what you have.

 

Thanks GT, after doing some research today I think I'm going with heads and TB. I've seen it mentioned on the boards, there's a car in the 10s with a 168, more evidence its not the pulley.

 

I wouldnt bother wasting money on heads.I would go 82mm TB and put that extra money into a renntech carbon airbox,carbonio python intake tubes and TTM intake scoops to get the most air into your engine.

then down the road upgrade to a 180 pulley etc.

 

I dunno....Exotic Metal put some SERIOUS power down when he installed the heads. Although I have yet to see a before and after dyno of the heads alone so maybe it's not as much as I'm thinking it is.

 

True.. But the heads were $3,500 or more, and Exotic is to the point where that was the next step.. If the OP were to put $3,500 into other mods (cf air box, python tubes, and a bigger tb) he may actually get more power from those mods..

Just a thought

 

You may be right...though I don't think I've ever seen a dyno on the CF airbox nor the python tubes either.

 

There definitely good for some power.. Skratch gained 2 mph in the 1/4 mile just from the RennTech air box..

 

I have yet to see a better flowing head not make more power. Im sure in Brooks case he'd see much more benefit since he needs as much flow as possible running a 200mm pulley. Would be nice to see what those heads make on a mild setup like mine.

Are the intakes really that restrictive? There are 55k cars making over 500bhp with stock boxes.

I cant get over the low boost #, anyone have boost reading with a similar combo 168 pulley with stock TB
RPM Boost lbs.
6233 8.655128