lookinco

So this is a follow up on my previous thread regarding the boost curve question on the kraftwerks kit.

Last week I was noticing the jerkyness of my boost gauge as shown here in the video:[media]http://www.youtube.com/watch?v=Vxg03Hg1RJY [/media]

I tried to look for boost leak and belt slip but it all seems to be fine. I then took out the bypass valve and found this.



The valve is all damaged. The inside is damaged as well but I was not able to picture it. The valve was not able to seal tight under boost so we thought that contributed to the boost jerkyness.

We replaced the valve with a Forge Fast Road Closed Loop Diverter Valve:



We then proceed to make a few dyno runs:



We ran a total of 4 runs. Peak boost was consistent at 7.3lb, 290whp, and 188lb/tq.

The numbers are pretty disappointing to say the least. Compared with the kraftwerks dyno for their AP2 Base Kit, I am making less horsepower and torque, but mine is supposed to be the high boost kit. So I am suspecting that something must be wrong with my car.



Here is a list of what I have in my car:

AP1 JDM (11.7cr) Short Block
Alaniz Ported and Polished Head
J's Racing Header
70mm test pipe
Greddy TiC Turbo Exhaust
Snow Performance Meth injection (50/50 mix) with a 375ml jet. The variable controller is set to activate around 4psi and peak at around 10psi.

More background story. I actually blew up a Rotrex before. I bought an Ap2 kit because I had a brand new Ap2 engine. The engine blew due to some stupid installation error. (They swapped an airline with a coolant line.) The engine ran for 4 seconds and a rod shot out of the block. I then got the AP1 engine and installed the kraftwerks. We were out tuning one day trying to tune the high rpm section in vacuum so we kept the rpm at over 7500rpm for a short while. Suddenly there was a loud squeak and the car wasn't boosting properly. We then later found out the sun shaft snapped and the rotrex is toasted.

Contacted kraftwerks and they said we overspun the charger with the Ap2 pulley on the Ap1 and so no warranty was offered. I had to purchase another brand new rotrex unit and got the Ap1 high boost pulley.

Here is a dyno graph when I had the AP2 pulley on the Ap1 engine.



Notice how the numbers are so close to the dyno I did yesterday. Peak at 307whp and 185lb/tq.

Does anyone know the size of the pulley for the AP2 highboost and AP1 highboost?
I tried to measure my pulley in the car yesterday and it was around 115mm. I measured the Ap2 pulley and its around 110mm. Is this correct?

DeadZero

and thats on dynapack.. your probably making 260-270hp on dynojet/dynamics.

something is definitely wrong with this set-up

lookinco

Yes i believe so as well.

Could it be boost leaking somewhere? But looking at the boost graph it seems like a boost leak would make a less linear curve.

camuman

why does the tq graph look like the bering sea during deadliest catch? i feel theres a boost leak, slipping belt, or that head is killing you.

man, after all the crap u have been thru, this must be icing on the cake.

my one concern is that boost started to build at 7-7500k and then it drops again. when your blower grenaded, did u clean out the intercooler? might be an obstruction some where. just a thought.

lookinco

They did say they took a lot of time cleaning out all the junk in the intercooler, but i guess it is possible that it was damaged somewhere.

camuman

did they pressure test it after? could be a leak.

well, even when you had the ap2 kit on an ap1 you were down on power. kinda brings me back to the head. thats a pita to test though. ask juntuned or kewlwhip, one of those two had KW hi boost and a built head, but didnt get good results.

juntuned

The AP2 high boost pulley is 100mm (for certain) ..... and the AP1 high boost is I think 110mm to compensate for the increased RPM....

Man, I look at your mod list and you should be almost at 400..... WITH A METH KIT you should be well over 400 for sure. I was contimplating getting that snow kit, Im interested to see how you have it mounted/set up and how you like it? Obviously you cant be too impressed with it at this point because of your numbers.

sigh, heres what I would do if it were my car and in this order...

1) who tuned this car? yourself, a buddy that claims to know what he's doing? no offense Im just making sure the low numbers are not a culprit of BAD tuning. I did a fair amount of research before when I wanted to go higher compression 12:1, and was told every time that I MUST be an EXPERT tuner and the car would need weekly adjustments to adapt to different conditions etc. Well, it sounded like more hassle than it was worth! I suspect even if your problem isnt in the tune, that you need to keep a watchful eye on this aspect due to your increased compression. I would just get the AP1 greddy emanage straight from KW and hook it up and run your car on that tune. If it dyno's anywhere near 360 you know that was your problem. Maybe OJR will send u an emanage just to test.

2) did you buy that alaniz head from sideways or have you had it for awhile? From my experience you wont gain hardly any power from headwork with this kit. I dont know if its s2k's in general or just how the head flows with the blower, at any rate the head still shouldnt HURT you that bad. I would still eliminate this as a factor by reinstalling a stock head.

3) I have that same forged motorsport BOV, and it works great... I think im running the green spring which is the softest of the three. I dont think this is an issue..... I actually vent mine just to atmosphere now.... (kind of makes a whistling sound)

4) what spark plugs are you running? That plays a bigger role than I thought previously.... you should be good with the BKR7E stock heat range.... or even better go with the BKR7E-E

The only other two variables are the block itself, and the blower and charge piping! make sure you have the blower cooler hooked up properly and everything flows in the proper direction. Also what map sensor do you have? factory should be good....

In regards to the belt slipping, I would run an 82 inch belt...... as opposed to the 82.5. Clean everything to insure there is no oil causing your belt to go haywire and slap on the slightly tighter belt. (you may need to mill off the outer flanges on the tensioner in order not to make contact with the crank pulley) On mine it ever so slightly touches, I havnt milled the tensioner pulley yet!


All you can do is take it one step at a time....

lookinco

Here is a few more things that i have missed in the list:

I am also running K-Pro, RC750cc injectors, Walbro Fuel pump, SOS 3bar map sensor, and a FPR.

How do you measure the diameter of the pulley? Do you just measure from the most outside lip? If that's the case than i am CERTAIN that the pulley i had on the blown charger is 110mm. I will take a picture tonight to double make sure. If that's the case then it means my charger didn't blow up because I overspun it. But again i will double make sure tonight.

1. The car was tuned by a very reputable tuner in the area. It was tuned both on the street and dyno. AFR is kept on the safe side at around 11.5 due to the high compression. We double made sure it was not detonating.
Kraftwerks sent us a basemap on the Kpro and we went from there.

2. I bought the head from sideways. Apparantely it was the last head done by Alaniz. I don't have any flow numbers for the head with me but sideways assured that it flows a lot better then stock. I guess we could swap the stock head back but like you said I do not think that it could cause that much performance loss.

As for spark plugs I am using some copper spark plugs right now but I have to double check the model number.

I guess first thing i would do is to make sure which pulley am i actually using.

juntuned

oh.... unhook your boost gauge.... hook it up like this... vacuum directly from the manifold to the BOV.... (see the furthest inside right nipple on the manifold runs directly to the BOV). All your T hoses are confusing me...

lookinco

I guess I will try that tonight. My bov is tapped from the same line except I had an extra T to hook up the boost gauge.

The line going to the left goes to the bypass valve, and the line going to the right goes to the boost gauge.