wheel spin
10-21-2009, 10:31 AM
#1
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wheel spin
I've got a mostly stock 87 930. The only mods are headers, B&B exhaust, 1 bar spring, and B6 intercooler with removed slide valve. My turbo seals went south so I replaced it with a K27 7200 about a month ago. After the replacement and break in period I was surprised to find that my car would now destroy the rear tires when hitting boost in 1st gear. I'm not sure if it's the cooler temperatures, the turbo, or a combination of both. I've got small tires for the rims (255/40/17 on 11" wide fikse in back). I'm considering going to 315/35/17 rear and 245/45/17 front. Is this normal for my setup? Any opinions/suggestions?
Last edited by fletcher0780; 10-21-2009 at 04:06 PM.
10-21-2009, 02:29 PM
#2
Same wheels (fikse) Almost the same sizes 315/35/17 Rear 255/40/17 Front.
It handles great.
If you want to see photos go here. http://www.flickr.com/photos/14150269@N07/
You can enlarge the photos.
Fitment is very good. Got great tires cheap here: http://www.tirerack.com/tires/TireSe...er=17&x=27&y=8
It handles great.
If you want to see photos go here. http://www.flickr.com/photos/14150269@N07/
You can enlarge the photos.
Fitment is very good. Got great tires cheap here: http://www.tirerack.com/tires/TireSe...er=17&x=27&y=8
10-21-2009, 04:30 PM
#3
You might be having an issue with you differential getting overpowered now. Smoked is what I like to call it. If you still have the stock LSD in it or an open differential, it may be time to make a change, or at least get your current differential overhauled.
What happens here is that as a differential starts to wear out, the plates no longer stay engaged, Locked, thereby allowing one wheel to break away and Smoke the differential plates, this can result in a fairly large amount of wheel spin.
The Porsche differential has only 4 plates in it, 2 per side. You should in my opinion upgrade to a OS Giken differential, and I would be willing to bet that some of your wheel spin issues will be addressed.
I hope that this information has been helpful and we are doing a group purchase for Rennlist Members for the OS Giken diff if you are interested.
Warmest Regards,
Erik Johnson
GBox Sales Manager
(303) 440-8899 work
(303) 895-4828 cell
What happens here is that as a differential starts to wear out, the plates no longer stay engaged, Locked, thereby allowing one wheel to break away and Smoke the differential plates, this can result in a fairly large amount of wheel spin.
The Porsche differential has only 4 plates in it, 2 per side. You should in my opinion upgrade to a OS Giken differential, and I would be willing to bet that some of your wheel spin issues will be addressed.
I hope that this information has been helpful and we are doing a group purchase for Rennlist Members for the OS Giken diff if you are interested.
Warmest Regards,
Erik Johnson
GBox Sales Manager
(303) 440-8899 work
(303) 895-4828 cell
10-21-2009, 07:48 PM
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Something else to think about is your boost level. Do you have a mech boost gauge? You might be over boosting. My wastegate was bad and I was spinning the tires. Took me awhile before I realized what was happening with the stock (POS) gauge.
10-21-2009, 08:51 PM
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The first thing I did when I started having problems with boost issues was get an in dash clock replacement boost gage. It will tell you so much more so much sooner than that toy in the tach. Issues like turbo over boost and when the over boost protection device actually kicks in etc.
10-22-2009, 12:28 AM
#6
The first thing I did when I started having problems with boost issues was get an in dash clock replacement boost gage. It will tell you so much more so much sooner than that toy in the tach. Issues like turbo over boost and when the over boost protection device actually kicks in etc.
Id like one but the prices are crazy for that item. Just because of the "correct size".
10-22-2009, 12:59 AM
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Go to NHSpeedo.com and see what the prices are. I bought mine for about $250 plus $70 for the hose hookup kit. Pretty cheap if it saves your engine.
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10-22-2009, 07:42 PM
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I recently replaced the boost gauge sending unit, but that doesn't mean it's accurate. Both tires spin when it breaks loose, so I don't think it's the differential. There's no way for me to tell if it's overboosting, but the wastegate appears to be working correctly. I'll need to find a mech. boost gauge that matches my silver backed gauges.