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-   -   Did compression test: Turbo this engine as it sits? (https://www.miataturbo.net/engine-performance-56/did-compression-test-turbo-engine-sits-79313/)

iTurn 06-02-2014 12:37 PM


Originally Posted by concealer404 (Post 1136000)
So? Who cares?


The higher compression is a DOWNSIDE of the VVT motor, and not because it makes the motor weaker.

Wait, huh... Why?

Or do you mean how the higher compression is acheived?

concealer404 06-02-2014 12:38 PM


Originally Posted by iTurn (Post 1136064)
Wait, huh... Why?

Or do you mean how the higher compression is acheived?


Moar compression = less timing = failsauce.

curly 06-02-2014 12:50 PM

OMG, shhhhhhhhhhhhhut up.

How in the world a $1200 engine with "documented miles" in a $3000 car that currently has 170/170/170/180 compression numbers better? That's just nonsense.

concealer404 06-02-2014 12:53 PM

Doesn't matter, gained post count.

curly 06-02-2014 12:59 PM

No, I merged his posts down to 12. It'll buy is 10 minutes of PM quietness.

krissetsfire 06-02-2014 12:59 PM

lol @ psi talk. You picking out his turbo for him too breh? I agree with concealer. Run it till it busts.

I'm not sure why your last one went, your experience with tuning, or your plans but those compression numbers look pretty good to me. Anything that is within 10% across the board above 150 is pretty good IMO.

If you have everything running correctly and aren't stupid that motor will last for a good while.

If you want to switch to vvt they spool quicker. BUT you probably won't be running any big turbo anyway since stock block. Your spool should be quick anyway.

If you ever plan on going built motor you could just buy a vvt motor (in decent shape who cares about miles) drive around on that while you build your 94 bottom end and then plop the vvt on the 94 and be on your way.

That's my opinion.

jspadaro 06-02-2014 01:00 PM


Originally Posted by krissetsfire (Post 1136084)
lol @ psi talk. You picking out his turbo for him too breh? I agree with concealer. Run it till it busts.

I'm not sure why your last one went, your experience with tuning, or your plans but those compression numbers look pretty good to me. Anything that is within 10% across the board above 150 is pretty good IMO.

If you have everything running correctly and aren't stupid that motor will last for a good while.

If you want to switch to vvt they spool quicker. BUT you probably won't be running any big turbo anyway since stock block. Your spool should be quick anyway.

If you ever plan on going built motor you could just buy a vvt motor (in decent shape who cares about miles) drive around on that while you build your 94 bottom end and then plop the vvt on the 94 and be on your way.

That's my opinion.

Last one went (naturally aspirated) because I had an old, clogged radiator and didn't watch my temps at track day because I was busy giggling like a little school girl.

Definitely not the car's fault.

Yeah, that's true, although if I were looking to build it I'd probably just get another old engine to build. For the time being, I'm just eyeing like high 100's whp to start, stock injectors, and then try to go to low 200's, that's about it.

curly 06-02-2014 01:08 PM

You won't hit high 100s with stock injectors.

RX8 injectors are a superior design and only $28 each at Rockauto. They're 420, and good for 200-215 flywheel hp. That's at 80% DC, so plenty of headroom.

krissetsfire 06-02-2014 01:08 PM


Originally Posted by jspadaro (Post 1135853)
Thanks! I appreciate the sanity check.

I was figuring with the age and mileage I'd definitely be looking at putting in another one, but with that response in mind, I think I'll just pull it to do some refreshing (clutch for the turbo, RMS, VC gasket, WP, timing belt, coolant reroute).

I'll also look up more info on compression testing, thanks for the tip.


BTW I think this post is on the money. You're well within your means on your power goals. Stock injectors will be pushing it though.

edit: curly beat me to it on the injectors.

concealer404 06-02-2014 01:10 PM


Originally Posted by curly (Post 1136091)
You won't hit high 100s with stock injectors.

RX8 injectors are a superior design and only $28 each at Rockauto. They're 420, and good for 200-215 flywheel hp. That's at 80% DC, so plenty of headroom.


The RX8s will do more than that quite easily. The 95 is running pretty rich up top still and is taking 12psi to hit 84% DC. Made 220whp on 10psi. I could easily lean it out enough to keep it under 80% on 12-14psi on this car. (BUT PSI MEANS NOTHING!!!!)

jspadaro 06-02-2014 01:14 PM

That's very good to know. My approach is really to just do what I can probably with the FM voodoo II kit to save time and get some more power, and I was going based on their reported numbers.

I'm basically planning to pull the engine, refresh gaskets and seals, put in a new clutch while I'm there, coolant reroute, slap on a Voodoo II, shove it in, and see how it goes. Edit: and I forgot to add, getting a WBO2 as well of course.

I think any significant increase over stock is plenty for my skill level on the track for the time being.

Then later on, I figure I can ditch the piggyback for a megasquirt and look seriously at my injector options, and do the best radiator/fan upgrade I can get.

concealer404 06-02-2014 01:20 PM

Do it once, do it right.

18psi 06-02-2014 01:29 PM


Originally Posted by concealer404 (Post 1136066)
Moar compression = less timing = failsauce.

only for pump gas peasants

jspadaro 06-02-2014 01:29 PM

Well, googling the voodoo box again in response did get me thinking... The appeal here is having FM hold my hand without paying for a hydra.

If they're really that dangerous, I suppose I could go straight to a megasquirt, I just have no idea what I'm doing.

thenuge26 06-02-2014 01:30 PM

If you only ever want high 100s whp, do the voodoo now. If you even think you might want more power in the future, do the megasquirt first. Learn to tune it now, before adding a turbo.

concealer404 06-02-2014 01:31 PM


Originally Posted by 18psi (Post 1136104)
only for pump gas peasants


If i'm going to use E85, i ain't fucking around with a limpdick 10:1 motor, either.

jspadaro 06-02-2014 01:33 PM


Originally Posted by thenuge26 (Post 1136107)
If you only ever want high 100s whp, do the voodoo now. If you even think you might want more power in the future, do the megasquirt first. Learn to tune it now, before adding a turbo.

That... is actually a really good idea. I'll have to go read more. One thing I have searched for and not gotten a good answer on is whether I should spring for an MS3?

I know with a VVT motor it eliminates the need for VVTuner, but for my '94 motor that isn't a concern of course. Does the increase in table size and resolution make a big enough difference to warrant the extra $$?

concealer404 06-02-2014 01:39 PM

MS3 gives me prostate exams. In the right way.

18psi 06-02-2014 01:50 PM


Originally Posted by concealer404 (Post 1136108)
If i'm going to use E85, i ain't fucking around with a limpdick 10:1 motor, either.

as in stock rods?
or as in you'd go higher comp?

doesn't matter, I don't care.

lol

*edit: its a great dual purpose compression ratio IMO. run corn when you have it, back off slightly and run pump when you don't have corn. Going higher would make pump map difficult.

concealer404 06-02-2014 01:59 PM

All of the above.


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