Miata Turbo Forum - Boost cars, acquire cats. - 10:1 + turbo... tell me why/whynot

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- - 10:1 + turbo... tell me why/whynot (https://www.miataturbo.net/engine-performance-56/10-1-turbo-tell-me-why-whynot-58080/)

A lower static compression ratio will allow you to add more total fuel and air into the cylinder without detonation. More fuel and air yields more power.

This is inconsequential if the detonation threshold of your chosen fuel is very high. e85 has such a high threshold for detonation that detonation is not a major consideration, but to anyone running pump gas it is very important.

Quote:

Originally Posted by Doppelgänger (Post 731848)

The stock 01+ VVT engines are 10:1....and I'm running 14psi w/2560 on pump with no problems....been doing so for years. When I had an engine failure last year, I was pleasantly surprised to find pretty much no signs on detonation when I pulled the head. To this day the failure is still a mystery and wasn't a catastrophic failure...no holed pistons, no pretzeled rods, no bent valves...it wasn't boost/tune/fuel related.

Once I get my hands on a squaretop IM, I'll be on the dyno and going for 290+rwhp on my stock engine...or whatever I can get from the 2560 at 16-17psi.

How many times did you hang the tach at 6000rpm in 6th for 20-seconds?

Output aside, an 8.5:1 motor is probably much safer and will live a longer life at the racetrack.

"How many times did you hang the tach at 6000rpm in 6th for 20-seconds?"

LOL this reminds me of Corky Bell's book Maximum Boost.
Think he recommneded no more than 19 seconds at maximum power.

Quote:

Originally Posted by Techsalvager (Post 731881)

I want the VVT so I can increase compression out of boost hopfully netting power sooner

Yeah boizzz. VVT represent. I really could care less about revving 8k. I don't track it enough. I went with 9.5 pistons because e85 is in my very near future. I think if you are doing E85 10:1 would be fine, It just isnt something that I would do on pump gas.

Quote:

Originally Posted by shuiend (Post 731883)

Off topic, but why do you want a square top manifold so much? Why not do one of the honda manifolds?

A) I want to find out how much benefit there is to it on a boosted car.
B) I want a IM that is OE because I don't want to bother with cutting, welding and fitting. Not knocking the Honda hybrid IMs, I would do it, but I want to try the squaretop since it's a direct swap.

Quote:

Originally Posted by musanovic (Post 731879)

can you share your timing map?
Please
just trying to compare mine and yours.
or you can PM me.

I'll see if I can find a map at work and PM you for your email addy.

Quote:

Originally Posted by hustler (Post 731900)

How many times did you hang the tach at 6000rpm in 6th for 20-seconds?

Output aside, an 8.5:1 motor is probably much safer and will live a longer life at the racetrack.

Honestly that argument is getting old Hussie. I know, as well as pretty much anyone on here with any sense, that there is a big difference between a track car and a street car. Honestly, most of the information posted here, and threads like this, pertain to street going steups...which 98% of us have. What works for years on the street is fine to discuss, which is what I am assuming this thread is aimed at. And if you don't think I'm hard on parts and break weird shit.....don't make me list of the oddball shit I've had to replace. As much as I wish the world was a racetrack, it simply isn't.

hustler is missing the argument where real race teams would run the ragged edge and just carry spare motors instead of worrying about how many race days it will last.