Rageous
New member
Can someone tell me the proper techniques and specs for compression testing on a 91 Turbo please and thanks!
Compression?
- Thread starter Rageous
- Start date
fireflyse
Active member
Service manual Turbo supplement states any procedures not listed in the supplement will be found in the factory service manual. Compression test is not listed, so standard compression test is performed. 180psi across the board would be great, all testing done at wide open throttle with all plugs removed.
Rageous
New member
That’s the thing, wouldn’t a N/A and Turbo’d car be different specs?
How low compression is too low?
Initially when I bought car 2 years ago I did a compression test (one plug at a time & not WOT)
iirc numbers were between 150-140
How low compression is too low?
Initially when I bought car 2 years ago I did a compression test (one plug at a time & not WOT)
iirc numbers were between 150-140
fireflyse
Active member
The service manual states that the compression ratio on the Turbo 3 is 9.5:1 but I've heard as low as 8:1. Do the test at w.o.t to get as much air in there as possible. The engine should be warm too. No specification listed in the manual for what you should see. 180 would be for a new engine.
If your numbers were fairly even I wouldn't worry about it too much.
There is a great deal (like as much as 20psi) of variation between one test setup and another. I don't have Mk2 turbo (wish I did!) but my turbo car, an 89 Volvo 740 is in the 150's, my NA Swift GT is in the 180's--a new NA motor would bea good bit higher still.
There is a great deal (like as much as 20psi) of variation between one test setup and another. I don't have Mk2 turbo (wish I did!) but my turbo car, an 89 Volvo 740 is in the 150's, my NA Swift GT is in the 180's--a new NA motor would bea good bit higher still.
With brand new bore, NPR Honda piston ring, Vitara low compression pistons 75 mm (somewhere between 8:1 and 8.5:1; 0.013 & 0.015 ring gap) mint compression is 155 psi. The higher compression pistons can see up to 210 psi (this is usually after the head & block is planed). Ring gap can play into this also. Always WOT, pull the fuel pump relay fuse, and I recommend putting a battery charger on.
blueturbofly
Well-known member
its boosted. run it. no smoke out the tailpipe then all should be ok.
had one of my t3 with poor seals in the turbo. would smoke like a banshee at times, other times just fine. weird.
had one of my t3 with poor seals in the turbo. would smoke like a banshee at times, other times just fine. weird.