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Boost Leaks Make You Slow

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secongendsm

20+ Year Contributor
51
0
Mar 6, 2002
Salt Lake City, Utah
After a disappointing trip, scratch that – trips, to the racetrack a few weeks back we were stumped as to why. Ever since the motor swap (read about my over rev that resulted in spun bearings) a few months back I lost about six mph on the top end. Previously, even if I bogged the launch I could trap 130ish in the quarter mile. Now I haven’t been able to get above 124 mph. We thought we had the timing off – nope. I’ve been staring at my ECMLink logs comparing old good runs to the ones now – couldn’t see anything that jumped out. So we hit the track again.

This trip to the track I kept rolling out of the lights before the green. Clutch in, car rolling out of the beams. Next, I wasn’t able to get it into third gear. Seriously T. Talon?!? (her name, yes my car has a name) you’re going to be parted out like your many sisters before if you keep it up. Back in the pits my male BFF (BFF version of Jet Snow Moody only hairier) Travis noticed there was no fluid in the clutch master. Well fill her up! But where is all the fluid going? Never mind that now, my class is up! Filled and bled I repeated the same issue as before; rolled through the beams and couldn’t shift into third. Maybe my used (yes, used clutch – this was a budget build remember?) Act 2600 and six puck was done for.

Needless to say, T. Talon went on the trailer for the night. That was a disappointment because we had a handful of UTDSM’ers coming to run the midnight drags with me.

The next day we started looking her over trying to diagnose my two new issues. A good eye by the husband caught the clutch master rubber hose cut. Weird but we never saw any fluid anywhere. Fixed that and bled the crap out of the system. One problem down, now what about my mph?

4843482787_e87c931be7.jpg


We figured it was time to go back to the basics and start with a good old-fashion boost leak test. As soon as the air started filling the system we heard a huge bleed off of boost. After some feeling around we found the air coming out of the HKS BOV (it’s not recalculated back into the intake). Now from what I understand the great thing about the HKS is the more boost you make the tighter that baby gets. That wasn’t the case right now. I’ve wanted one of those fancy limited edition flat black versions so here’s my chance. Ordered one from my favorite one stop shopping site – ebay and two days later she was at my door. Installed and boost leak free, I took T. Talon out for a test drive.

That’s my girl! She felt like she had her umph back! But that umph would be short lived. We pulled back into our shop and the check engine light popped on. If you’re familiar with ECMLink you know that you can disable all the boring CEL’s that hinder your go-fast umph. When this one didn’t go away quickly (sometimes I see a quick flicker of the light with phantom knock) I got concerned. While waiting to grab the laptop to check the code, we heard bubbling from the overflow bottle. The light ended up being from the car overheating. Hmm, that’s weird. Yes, it was hot out but I’ve never had any issues with overheating. Head gasket? A boost leak test didn’t produce any bubbles in the coolant but a hand checking if the fans were blowing . . . Bingo. One of the fans wasn’t kicking on – Fixed. Now where is that huge puddle of oil under the car coming from?!?

There has always been a small leak we’ve been unable to pinpoint since the new motor went in, but that drip turned into a puddle. When you’re finally able to push that 30 psi through the motor without a boost leak, all that pressure made the leak worse.

4844096132_abb832c368.jpg


The driver’s side of the motor is coated in oil. Since we can’t see the leak we assumed it was coming from the front case. Guess what we’re in the process of right now? That’s right – oil pan dropped, front case off. Looks like a gasket used for the front case was leaking right below the water pump.

Right now T. Talon is still stripped down showing her bare block, but she’ll be back together by this weekend and ready for Rocky Mountain Raceway on the 6th (cross fingers).

I need no reminder of why I named her project “What was I thinking“. She’s doing a good job reminding me!
 
Thats a good project name, I'm constantly finding new problems here and there, and once or twice a week i see a new droplet of oil under the car... It burns me up and none of my buddies understand the frustration LOL, none of them own DSM's so they wouldn't understand... Now I know you're running a completely different BOV but, I'm wondering if my boost leak could be coming because mines too tight? Its the adjustable Greddy RS And ever since I went back to the T25 I can't build above 5-8 PSI but when I first did the install it went up to 10 just fine Theres no telling... Ever! Lol but if you know about the BOV hook it up with an answer please? P.S it is recirculating
 
project1g;bt9307 said:
Thats a good project name, I'm constantly finding new problems here and there, and once or twice a week i see a new droplet of oil under the car... It burns me up and none of my buddies understand the frustration LOL, none of them own DSM's so they wouldn't understand... Now I know you're running a completely different BOV but, I'm wondering if my boost leak could be coming because mines too tight? Its the adjustable Greddy RS And ever since I went back to the T25 I can't build above 5-8 PSI but when I first did the install it went up to 10 just fine Theres no telling... Ever! Lol but if you know about the BOV hook it up with an answer please? P.S it is recirculating

Have you checked for boost leaks?
 
What gasket are you going to use for the front case to fix the problem? I've had a leak from there since forever.
 
Also have a small leak from the front that I can't pin point since finishing the engine build. But when replacing the front case gasket to try and stop it I found some rtv in the relief hole for the oil pump sprocket shaft that was causing the sprocket seal to push out after fixing that there was still a smaller leak.
 
Have yet to check for them seeing as how I'm waiting on my oil pan, but once it goes in I'll be putting a fine ear for that famous hissing noise... If not I'll smoke test it BUT I have heard of the bov spring being too tight can cause the boost to do what mine is doing....
 
ziggo0;bt9327 said:
What gasket are you going to use for the front case to fix the problem? I've had a leak from there since forever.

Another stock one. The other one got buggered up on install.
 
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