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Compression drop for turbo?

Posted: Tue Jul 27, 2010 10:34 am
by akio_fr03
Hi guys

Just wondering do I need to do a compression drop on my motor for turbo?
How much do I need to drop t?

93 1.6l

Thanks

Re: Compression drop for turbo?

Posted: Tue Jul 27, 2010 10:52 am
by Juffa
If you think in terms of a holistic solution then the standard compression ratio will be fine. By this I mean you need to be thinking in terms of boost pressure, fuel managment to meet the boost requirements, manage intake air temp, manage the coolant temp.....and the like.

For instance I ran 9 pounds of boost. Used a FM/Link ECU, with 330cc injectors to manage the fuel, had a intercooler fitted to manage the intake air temp and a more effective radiator.

Have a read of the various posts on the big forum and on miata turbo net forum. You will see that there are a number of people running high levels of boost on standard engine internals.

J.

Re: Compression drop for turbo?

Posted: Tue Jul 27, 2010 11:08 am
by Benny
It very much depends on how much boost you want to run.

If you are happy with 8-9lbs, then you can leave the compression ratio as it is, but if you want to run higher boost levels, then you may need to lower your compression a few points.

Re: Compression drop for turbo?

Posted: Tue Jul 27, 2010 1:08 pm
by akio_fr03
Thanks guys, I'm planning to run 7psi so it should be. Fine

Re: Compression drop for turbo?

Posted: Mon Oct 18, 2010 12:33 pm
by ShadyDeals
Reviving and old thread but a related turbo question. My newly acquired NA with an old Hitachi HT18-bm turbo off a 12A rotary engine is blowing a heap of smoke. I was quoted 1100 on a rebuild or 1500 on a custome pieced together Garrett ball bearing water cooled. I am leaning toward option B obviously.. I am trying to do as much of this project myself as possible so am just wondering where everyone else with a water cooled tapped into their water jacket. Someone said the heater lines are the best option?? Any pictures would be greatly appreciated...

This is my virgin post on this forum, i will do an official introduction with some pictures soon. I also have access to some wholesale parts but more information on that at a later date. :)