Miata Turbo Forum - Boost cars, acquire cats.

- DIY Turbo Discussion (https://www.miataturbo.net/diy-turbo-discussion-14/)

- - Planning my new build (https://www.miataturbo.net/diy-turbo-discussion-14/planning-my-new-build-27475/)

Quote:

Originally Posted by Markp (Post 325010)

Couple of points I disagree with.

1. Studs are re-usable. I like them for that reason and they make installation and removal of the head a snap. I like the fact that studs provide more even torque but as you note, it's overkill. It's the fact that you can reuse them forever that makes them worth it.

2. Built motor, 8500 RPM rev limit makes sense for ********... it's not that you make "no" power, but you make no additional power... 300 RWHP at 7000 is still the same 300 RWHP at 8000 RPM... for ********, this extra rpm can be useful.

3. Compression ratio. He is running VP109 race gas, so using an 11:1 compression ratio makes perfect sense unless he wants to run 35 PSI of boost. Really it will help the turbo spool earlier and it will make massive torque at relatively low boost. Once again, ******** is not about making the most power, just enough power to over-whelm the tires at will across the widest RPM band. If he was running pump gas, I would agree with you.

Mark

Sounds like we agree on the studs.

On the RPM part, I see your point. But again, I don't think I've EVER seen a miata that made usable power after say, 7500. I'd "guess" any miata that's making 300 whp at 7K is making say 270 at 6K, and making more like 250 or less at 8K. 8.5K it's probably like 220whp. So having the rev range may be nice, but you reach a point FAST where it's no longer usable w/ respect to making power. If it were true that you could make 300whp at 7K or 8K, then yeah, I'd agree. But this ain't a B16.

And I agree on the compression ratio part. When I wrote this, I was kinda assuming this thing sees street use. If it's just a track car, go big.

Just a track car.

Thanks for all the info guys!!

Quote:

Originally Posted by patsmx5 (Post 325112)

https://www.miataturbo.net/gallery/f...geot_run1b.jpg

Yep you are right on the numbers, ASSUMING stock cam timing and no additional timing. Change the timing with cam gears and you can shift the powerband up 500 RPM easily. Adding ignition timing in this case would have fixed much of the loss of upper RPM power. We are both pretty much in agreement, but 250 RWHP at 8k RPM will do the trick for ********... I wish I had the chance to tune the car because it had more high RPM power left in it.

OK folks, this build is coming close to the end.

After all that I have learned I dont know the answer to a pretty dumb ass thing. I think its dumb ass anyway.

I had a vac hose running to the IC outlet of the turbo for my boost controller.
The new turbo I have does not have a nipple. I am not exactly sure what that vac line is doing for the ProfecB II boost controller.

Is there some where else I can plug that line to- to serve the same purpose. Even serve it better??

Thanks everyone.

I hope to get some thumbs up on my Dyno plot I should have in a week or 2.

Pre throttle body, and post intercooler.

btw, what did you end up doing/going with?

Thanks bro
After all is said and done I will give greater detail. Things are still in the mix.
pistons
rods
crank mod
bigger valves
valve springs
a little bit of head work, mild bowl blending
Intake manifold modded
racing bearings
SPA turbo
3" down pipe
3" pipe all the way out
billet oil gears
dual feed rail

I think those are the mods so far.

I guess if you're going to build a drfit-buttsex-ing machine, this is the way to do it.

I hope one day to build something like this.

I wouldn't mind seeing more pics of the head work you did. This is something I'm sure a lot of us would like to tackle, but there's not a lot of BP specific info on.

GS thanks for the someone what back handed compliment. Maybe I will do some time attack action and see what happens. Then I can have grip buttsex..

I actually dont have many pics. My machinist has some and I am waiting for him to pass it on. It may take a while though.

He just did some mild blending of the bowls. I saw some work on here people had done and it def wasnt that extensive. Knocked down and cast/hi points and blended any edges. It was a full port and polish.

This thing should be pretty serious once its tuned. i am hoping for a dyno plot like Pauls. That would be ideal for me. Since I have quite a different build it will likely be a bit different.