Slowest turbo Miata ever
#201
From what I understand if you are going for big turbo power and not running E85 you should go with 8.6:1 pistons. You will not be det limited and you can throw a **** ton of timing at it and make phenomenal power. I remember this discussion somewhere on this forum. I believe both Hustler and Savington said that 8.6:1 on pump gas will allow for the most head room.
#202
This. I've never built an engine, but the TSE pistons page recommends 8.6:1 for their turbo builds. That's what I got, because Savington has probably built more turbo miata engines than just about everyone else on here. The MSM is 9.5:1 because it is an awful hack job that is more marketing than engineering.
#203
Supporting Vendor
iTrader: (1)
Join Date: Sep 2010
Location: Lake Forest, CA
Posts: 7,982
Total Cats: 1,024
We get pretty good gas around here very high quality 94. Plus i have a few stations that sell e85. Not that i would need e85 for 9.5:1. Just because it's that "little bit more" in case i ever want to do silly things and make a ton more power than my current goals. Plus that CR will make my quick spool even quicker, and i like that. With that being said, i have not found any actual data showing how much of a difference 9:1 and 9.5:1 really is. I'd assume there would be some, if i were to even notice i doubt it. Maybe someone can prove me wrong.
The plan was to tear town the engine and get everything measured and figured out before ordering pistons. Like Vlad said i'll probably not bore it over unless i have to. 83.5mm seems to be what everyone is doing.
Edit* lower compression, crank the timing? I'm afarid to add timing, i'm tuned way conservative now.
The plan was to tear town the engine and get everything measured and figured out before ordering pistons. Like Vlad said i'll probably not bore it over unless i have to. 83.5mm seems to be what everyone is doing.
Edit* lower compression, crank the timing? I'm afarid to add timing, i'm tuned way conservative now.
#206
Like Ryan G said, if you think you might want to go for big power later, you want to start with lower compression. 9:1 is a nice medium because you've got enough compression that it runs good off boost, but it's not too high of compression. If you go 9.5:1 you won't be able to run as much boost down the road. Yes you'll have more area under the curve, quicker spool like you said, but the headroom isn't there if you go higher compression and don't run E85.
#207
Supporting Vendor
iTrader: (1)
Join Date: Sep 2010
Location: Lake Forest, CA
Posts: 7,982
Total Cats: 1,024
Won't be able to run as much boost? Are you're talking more than 20psi? There are members here that have made 350whp on 9.5:1 w/ pump gas @ 20psi. I guess the Idea is you don't have to run as much boost if you have higher compression... The seesaw could go back and forth all day on this discussion though. It's preference. 8.5:1 all the way to 10:1 are all doable on pump gas. 10:1 having the smallest margin of error. 9.5:1 in my opinion is not a terrible option though.
Last edited by turbofan; 02-07-2013 at 04:02 PM. Reason: first sentence was retarded
#212
Supporting Vendor
iTrader: (1)
Join Date: Sep 2010
Location: Lake Forest, CA
Posts: 7,982
Total Cats: 1,024
Dillon, did you ever ride in Bryan's car? Is yours the fastest Miata you've ridden in? you might have to take mine for a spin when the weather clears up (if I still have it). 300hp would be fun but I don't really feel like I need any more than I have right now. 400 hp just seems silly!
#214
Elite Member
Thread Starter
iTrader: (5)
Join Date: Oct 2011
Location: Detroit (the part with no rules or laws)
Posts: 5,684
Total Cats: 806
Why lol at MPG when building a high horsepower turbo engine? If you do it right, there's no reason you can't have decent MPG when you're not on it, and amazing power when you are. Yeah if you're talking about 500hp then sure, that's pushing it.
Dillon, did you ever ride in Bryan's car? Is yours the fastest Miata you've ridden in? you might have to take mine for a spin when the weather clears up (if I still have it). 300hp would be fun but I don't really feel like I need any more than I have right now. 400 hp just seems silly!
Dillon, did you ever ride in Bryan's car? Is yours the fastest Miata you've ridden in? you might have to take mine for a spin when the weather clears up (if I still have it). 300hp would be fun but I don't really feel like I need any more than I have right now. 400 hp just seems silly!
My car is not the fastest miata i've been in. I was in a built engine, gt2860, begi S4 car on 30psi. BUT like all begi manifolds he blew a crack in it (on what i believe he said was his 4th manifold). Though, when i rode in it, we were on the dragon, so all the power was not usable. But it did feel good. Still haven't been in Bryan's, not sure i want to ruin his seats.
My main dilemma will be: Do i want to try and make the 5 speed last, or just shoot for the stars, blow it up, and find a 6 speed... Hmmm. Also my clutch is rated for 318ft/lb... We'll see.
#215
Well damn... that sounds like a tall order buddy.
My car has never seen higher than 25mpg, even on a whole highway tank.
And a fun and highly useless comparison, my MX6 makes more power, has a MUCH lower compression ratio (7.8:1), weighs more, and is shaped like a brick. 41mpg on the highway.
My car has never seen higher than 25mpg, even on a whole highway tank.
And a fun and highly useless comparison, my MX6 makes more power, has a MUCH lower compression ratio (7.8:1), weighs more, and is shaped like a brick. 41mpg on the highway.
#217
Supporting Vendor
iTrader: (1)
Join Date: Sep 2010
Location: Lake Forest, CA
Posts: 7,982
Total Cats: 1,024
Well damn... that sounds like a tall order buddy.
My car has never seen higher than 25mpg, even on a whole highway tank.
And a fun and highly useless comparison, my MX6 makes more power, has a MUCH lower compression ratio (7.8:1), weighs more, and is shaped like a brick. 41mpg on the highway.
My car has never seen higher than 25mpg, even on a whole highway tank.
And a fun and highly useless comparison, my MX6 makes more power, has a MUCH lower compression ratio (7.8:1), weighs more, and is shaped like a brick. 41mpg on the highway.
#218
Well damn... that sounds like a tall order buddy.
My car has never seen higher than 25mpg, even on a whole highway tank.
And a fun and highly useless comparison, my MX6 makes more power, has a MUCH lower compression ratio (7.8:1), weighs more, and is shaped like a brick. 41mpg on the highway.
My car has never seen higher than 25mpg, even on a whole highway tank.
And a fun and highly useless comparison, my MX6 makes more power, has a MUCH lower compression ratio (7.8:1), weighs more, and is shaped like a brick. 41mpg on the highway.