Well after the THIRD rebuild of the motor I have been out testing things.

Whilst my brother was driving and I was tuning on the FAST we went for a blast. FORTUNATELY I had logged the run.

Started in third gear at 2850 rpms. Excelerated to 5500 rpms. Boost went as high as 13.4#'s. Air fuel PERFECT and then my brother went to change gears. At that split second - and thus unable to tell if the lift of the throttle caused the problem - there was an 'explosion' a grinding vibration that was scary as hell. Was it the clutch, tranny, motor? No lights on the dash so i assume oil pressure is still good.

Its the blower. The impeller has fouled the housing badly. The boost side of the blower tubing has a film of grey aluminum sludge. As I spin the impeller there is a tasty grinding happening. The differance in the set up THIS year is that I installed the SDCE bracketry. With 13.4 #'s at 5450 rpms I wonder what the boost is going to be at 6200 rpms? Previously the highest boost I had ever seen was 13.4#.


So what happened? What should I be looking for? What do I do? Send it to ATI for a rebuild or is it not worth it? Buy a new one? What about damage to the motor? Once I had taken the blower out I disconnected the coil wire and turned the motor over. The motor sounds fine. However, I noticed a little oil at the back. Almost certainly another leaking rear main seal. I plan on installing an electric vacuum pump.

Almost certainly unrelated but, the water out of the rad was dirty. Had very fine dirt in the water. It is brownish, not silver so I hope its just general dirt.

So question guys, any ideas why it happened? Whats it going to cost for a rebuild?

 

What size pulleys are you running?
Which bypass valve are you using?

It would probably only be around $1,200 to fix the blower vs $2,000 or more for a new or used one.

 

15# pulley, ATI stock surge valve AND an HKS blow off valve.

There was no apparant problem with the vacuum lines to either of them - although they both use the same vacuum source.

 

My bad, maybe I should've been more specific.
What diameter blower pulley are you using? (ATI doesn't make a 15# pulley, they go by the diameter of the pulley.)
What diameter crank pulley are you using?

 

I was afriad you would ask that- my bad becauese I suspected that IS what you were asking and was hoping to get off light. LOL

I'll have to measure them but I THINK it is a 7 inch and a 3.75. But that is from memeory from 2 years ago.

 

Well, it doesn't sound like you overspun the blower or anything. Maybe just some bad luck. Did the blower have oil in it? Did it sit for a long time allowing the oil to run away from the bearings? The only other thing I can think of is, if you weren't getting a good vacuum signal to your bypass valves, which would cause the boost to have to go back out through the inlet of the blower, thus causing it to surge and crashing it.

 

Well it hasb been sitting BUT I put freash oil in AND I have had it on the road for about 300 miles. I agree, the surge valve seems the likely culprit but how does one know for sure. The vacuum line was plugged in.

I'll have to call ATI tomorrow.