Either I'm losing my mind or my SE has lost power

[luzinit]

So, I have a SE that is totally stock minus a few bits that were taken off by the previous owner, namely the stock boost control solenoid. Actually it does have one mod which is a nitrodann TBI pipe.

Lately I feel as though the car feels very linear in second and third gear. It no longer has that notorious SE power surge after 5000rpms.

Thought it might have been a boost or vacuum leak, so I installed a boost gauge recently and it building close to 10psi on what I assume must be wastegate pressure. Vacuum at idle is around 20psi. On a cold night I can no longer hit the violent boost/fuel cut.

Checked all hoses and lines and all appears ok. I even took off the heat shield and checked manifold nuts incase they were loose.

Mania had a quick look and drive of my car during the last service and they reckon it was fine, but it was also a very hot day so it was probably very hard to tell.

Anyone have any ideas on what else I should be looking for? If anyone has a stock SE in Sydney and open to taking me for a spin, that'd be awesome. At the very least if my car is normal then at least I can sleep at night again

Thanks
Tony

[pepejesus]

I assume the Nitrodann TBI pipe is the 'elbow' just prior to the throttle body? I know you've said you've checked the hoses but it would be worth double and triple checking that it is clamped and sealing correctly, along with all of the clamps along the intake path (intercooler, etc).

I had a similar problem with mine recently and it turned out to be the compressor inlet tube. I've got a BEGi intake so mine will be different from yours, but worth checking that as it's just two 6mm (I think?) allen bolts. Mine had worked loose so I put some gasket on where the turbo compressor and the outlet pipe mate up, then loctited the bolts that hold the two together.

Is the car running hot? That will sap power pretty quickly too.

[ManiacLachy]

Did the NitroDann elbow come with a replacement Blow Off Valve, or are you still using the stock unit? The stock is known to leak.

When you say the previous owner removed the stock boost control solenoid, I assume he replaced it with an aftermarket MBC of some description? Or is it actually just running wastegate pressure? 10psi sounds high without some kind of bleed off. Probably not related to your power loss, but I was curious.

My SE lost some power with a crack in the exhaust, I presume it was creating turbulence which was adding back-pressure. During this time I noticed a reduction in the 5000rpm hump, at the time I was stock ECU, with exhaust and intake, so the hesitation was normally quite pronounced. At the time my fuel consumption also went up, just another symptom for you to keep in mind.

[luzinit]

pepejesus - yep it's the elbow prior to the throttle body. I will check again, the ones I haven't checked properly are the clamps to the intercooler. I have checked the compressor inlet tube though, 2 big torx bolts, which I had to remove to take off the heat shield. Thanks for the suggestion though. How do you check whether your car is running 'hot'? Do you have a temperature sensor and gauge in yours?

ManiacLachy - yep it came with the BOV. How did you notice your exhaust crack? was it audible? In regards to my boost pressure, maybe it is 10 psi, maybe around 9 psi?? Bit hard to keep a close eye on the gauge whilst driving, especially as my gauge goes to 30 psi.

I really wish I had access to a hoist to go through and check it all!!

[ManiacLachy]

I had an odd noise over some bumps, I thought suspension, I couldn't hear anything odd from the actual exhaust though. I put the car on stands and gave a few things a shake, exhaust was really loose, led to a crack after the resonator.

[pepejesus]

pepejesus - yep it's the elbow prior to the throttle body. I will check again, the ones I haven't checked properly are the clamps to the intercooler. I have checked the compressor inlet tube though, 2 big torx bolts, which I had to remove to take off the heat shield. Thanks for the suggestion though. How do you check whether your car is running 'hot'? Do you have a temperature sensor and gauge in yours?

Sorry I should have said compressor outlet tube but it sounds like you knew what I meant, as it is two torx bolts.

I only have the stock temperature gauge to go on, but anything over halfway is getting hot and will result in a reduction in power. I found this out last time I was on track as I started bleeding time on the straights, looked down and the temp gauge was creeping up well past half way. The stock gauge is slow to react so it was actually the loss of time on my lap timer that alerted me before anything else...

This weekend I'll be making an attempt at ducting the air from the front of the car through the heat exchangers.

Cooling on these cars is marginal even at stock power, particularly if you're on your second radiator (plastic end tanks usually last about 10 years so I'd imagine there have been a lot of SE radiator replacements recently) and it's not been replaced with the larger SE specific radiator.