No power after Paxton installation, any ideas?

Hi,

I made a complete built up this winter on my RT/10 1994. But the car don´t gain power. With fully opened throttles the engine speeds up to 3000rpm and than there is no more power left. I sent a Logging File to Roeracing and he told me I have a boost problem, the boost is dropping of and the engine is going into vacuum.

I made a test run a few month ago, it was cold outside about 32°F. The car had a lot of power, but now I run the car on the streets, there is not much left?! Where is the boost going to? Does anyone have problems with the bypass valve? I used clamps on all hoses, even on the small vacuum lines I used zip tiess.



I used following parts:

Built Cylinderheads (RoeRacing)
CompCam with Supercharger grind
Roller Rockers
70mm throttle bodies
Bellanger headers
high folw cats & muffler (RoeRacing)
Paxton Novi 2000 (Tuner Kit)
Walbro dual Pumps
Aeromotive pressure regulator
Vec3
ATI Super damper

I made a belt tensioner by myself - becauce I got no answer of DLM.

My (AEM) pressure gauge shows strange things - sometimes. While the engine is idling it shows +5 PSI ?! It shows also +10PSI @3000 rmp and then it falls to +5psi. Sometimes it shows correct values like -10PSI while idling and about +2 PSI till 3000 rpm. But there is no difference while driving the car, there is absolutly no power after 3000rpm.

I placed the sensor under the intake manifold into the connection pipe between the 2 throttle bodies.

When I speed up slowly the engine goes without any problems over 3000rpm.

I also checked all things a few times, looks ok so far.

Maybe someone has ideas to help me.

Greetings

Jürgen

sounds to me like a problem with the tune.........the engine management........

Sounds like tune and probably belt slippage too!.

I'm betting on belt slippage. Are you seeing any dust particles around where the blower belt travels? Usually black dust, from the belt slipping. It gets worse at higher rpm.

did you pin the crank/pulley?

Hi,

I also thought the belt is slipping, I made a belt tensionier. I was careful not to overstretch it and maybe demage the crank shaft bearing.
But my problem always happens @3000 or 3500 rpm in each gear! The people told me, if there is slipping on the belt, than it´s just on higher rpm and not always just sometimes?

I pinned the crank.

Just tested the bypass valve, it looks Ok.

Sean Roe told me, after he checked my file, I have a boost problem.

Thanks for your help.

Jürgen

Looking at the graph you're not making any boost. What's your AFRs look like?

Does seem mechanical though. belt slip,bypass valve, or a huge boost leak. Is it a new unit?

Hi,

even before the boost is dropping, the AFR goes to 10-11 : 1

But this can´t be the reason for the dropping boost. The boost is increasing till 3000 rpm to aboout 2psi.

In the instruction manuels they wrote the number 8D204-010 the number of the bypass valve I´ve got is 8D004-010.

But I think there are no differences?

http://www.vortechsuperchargers.com/page.php?id=30025

I screwed the adjuster 50% more in to get more pre-load.

Jürgen

Maybe adjust it all the way one way and see if it makes a difference.

I have seen bad valves and even though your hose connections look ok you need to double check them all. When we do the installs we always "scuff up" the aluminum hose connections for grip.

Hi Mark,

how do you check the valve?

Jürgen

You will probably need to remove it and rig up a measurable pressure source to check actuation of the valve and then again for the sealing of the valve simulating boost. It will take some ingenuity, we had to piece meal some stuff together here to do it before.

Stahlhart said:

Hi Mark,

how do you check the valve?

Jürgen

Click to expand...

Hi Mark,

I think the Bypass Valve is the only way to loose about 32psi within such a short time. At the moment it´s removed and I checked it with compressed air and 22psi. Also the piston inside is moving smoothly.

Jürgen

Stahlhart said:

Hi Mark,

I think the Bypass Valve is the only way to loose about 32psi within such a short time. At the moment it´s removed and I checked it with compressed air and 22psi. Also the piston inside is moving smoothly.

Jürgen

Click to expand...

Did you do the cam/heads and S/C all at one time? Maybe the cam is wrong or indexed wrong and under boost the overlap is incorrect for blown applications, letting the boost leak through and out the exhaust? In that scenario it could run fine without the boost, just thinking out loud here.

Hi,

did a lot of tests today. I adjusted the bypass valve all the way, screwed it all in and completely out but there was no big difference. When I´m driving more then 3300 rpm (under full opened throttles) it sounds like I´m loosing the boost controlled (in every gear the same). You can hear it whisteling at this point.

It feels like the BPV is closing to maybe 1-2 psi and then open again @ about 3300 rpm and all the power is gone. While idling I was able to see, that the valve is open, after I pulled the vacuum/boost line it was closed.

I´m wondering why I have two different part numbers (8D004-010 on the valve and 8D204-010 in the installation guide). I was not able to find some information for 8D004-010.

I could get a greddy BOV in Germany, but don´t no if there are big differnences between a BOV and a PBV?

Could there be a problem with line loss because of a too small vacuum/boost hose? I put it on the smae ****** with a "T" (intake manifold) where I also conected the pressure switch for the 2nd Walbro pump and the map sensor for the vec3.

Hopefully someone could help me.

Jürgen

Yes, undersized vacuum to the bypass valve can create several issues. The first problem is typically surge with the valve wanting to chatter due to vacuum source being on the ragged edge of minimum required. I had this issue with the big red Procharger bypass on my F1A setup. Ran a larger dedicated line straight from the intake and never had another issue.

Vacuum holds the bypass valve open, so your issue with loss of power is a bit strange and less likely to be due to an undersized vacuum source since that would actually close the bypass and build boost earlier. Could still be a bypass valve mechanical issue.

Hi

after about two weeks and 1000$ later we found the fault. It´s the f**ing Paxton Airbox! I was sure, when I buy a Supercharger Kit everything should work well,...

With the Airbox on the charger there are just 1 PSI of boost and then there is a vacuum between the charger and the airbox.

I´m very angry about Paxton, they don´t answer e-mails and the quality of the parts is also bad (all plastic parts, "water" radiator, water pump,...).

I bought a new water pump (Johnson) an we made a complete new radiator and now I also have to make a new air intake...

Have a nice weekend.

Jürgen