cas951

It's been 4 yrs since I dynoed my car and they charged me $90.00 then. Not sure how much it is now.

This is their website.

http://www.dynospotracing.com/

Andial951

BTW - I have used this site to find local dyno places.....not sure how up to date it is.

Dynojet Research

UK952

Have a very good look at the hard pipe to IC connector they sometimes split underneath and then as the engine lifts it opens wider - if it is split you might get oil in the area. tightening r loosening the banjo bolt might place extra stress on it.
Good luck,
Tony

Sunnyvale-951

I looked over the IC couplers to the hardpipes very well. I loosened the clamps and rotated the coupler so I could see the whole thing. The looked brand new and were very flexible, no cracks. I also looked very closely at the coupler the connects the turbo to the hardpipe and the coupler that connects the hardpipe to the TB. All looked just fine. One thing I did notice is that the wires going to the ISV have begun to fray a bit. They are not shorting out but I'll need to fix that soon. I'll continue my search.

I was driving it today and noticed just how pronounced the boost loss was. It seems like as soon as it hits 15 psi it drops and keeps dropping down to 6 or 7 psi (even in 2nd gear). But it builds boost to 15 psi pretty quick (at around 3000 rpm in 2nd). I'm just wondering if the LBE is at fault or something else. I'll see soon enough if it's the LBE since 87944Turbo has generously sent me a couple different MBC's for me to test out.

UK952

A friends (new) accuboost did have a piece of dirt stopping the ball seating correctly, might be worth having a quick look inside the LBE,
Tony

Sunnyvale-951

I was thinking the same thing initially. I took the LBE completely apart and made sure everything looked fine and was seating correctly. It all looked fine to me so I don't think it's a foreign object causing problems.

Sunnyvale-951

Update:

I was just driving the car around again today checking things out. The boost definitely drops all the way down to 5 psi even in 2nd gear.

Also, there is a definite ticking noise in the engine compartment when I stick my head in when its running. I can't tell if it is coming from the header or under the intake manifold. The noise is at about 5 to 7 cycles per second at idle. The ticking noise increasing at the same rate as the engine speed increases.

I'm guessing it could be an exhaust leak. I don't smell exhaust in the engine compartment though when I'm poking under the hood with it running.

I also don't see any signs of coolant in the engine oil.

What else could be a ticking noise near the cam cover?

I'm guessing something like this could cause the boost loss that I'm experiencing.

Sunnyvale-951

Just wanted to add something. The car idles and runs perfectly besides the boost loss. No hesitation, no smoke, no rough running at all.

Brian Morris

Right when I got my car I thought there was an exhaust leak - a ticking. I had a mechanic look at it and he found it was the sound of air going through one of the intercooler pipes. If you put your hand on the pipe the sound went away.

--Brian Morris
89 951

Sunnyvale-951

Brian, I listened close to the intercooler pipes. The sound is definitely not coming from them. It's definitely coming from somewhere in the vicinity of the cam cover (either by the intake or exhaust manifold areas). Thanks for the thought though.

Anybody else have any comments?

cas951

My friend and I are getting together tomorrow for a short ride/ Want to join us? We could possibly compare what you're seeing with our cars.

Sunnyvale-951

cas951, you have a PM

SoloRacer

Are you sure the ticking sound is not just the sound of the injectors/fuel rail that are commonly noisy on these cars? I know mine "ticks" like you mention and I believe it to be normal.

Sunnyvale-951

So today cas951, a good guy named Ben (who also has a black 1987 951 with similar mods), and I got together to check out my car. It was determined that my car has an exhaust leak in the header area. We weren't able to determine whether it was a crack in the header or a possible bad connection between the header and the head or flange.

We think it might be a bad connection because one of the header flange nuts is charred black on one side. I'm going to gently try to tighten it tomorrow when it's cool to see if that makes a difference.

So it looks like my boost loss is being caused by too little exhaust pressure driving the turbine wheel when at higher rpms.

Anybody else experienced this upper rpm boost loss when they had a cracked/leaky header or cross-over tube?

Sunnyvale-951

Also, SoloRacer is correct, the ticking was coming from the fuel injectors (good call).