Miata LS3 Build Thread
Thread Starter
TECH Enthusiast
Joined: May 2008
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From: Carnation, WA
Should clarify ... *Western* WA/OR ... east of the mountains is pretty nice 4 season weather, if you don't mind a bit of snow in the winter.
Staging Lane
Joined: Jul 2020
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I remember reading Tony's thread on these heads and him saying these are 470rwhp heads on a 6.2 with killer stock like throttle response after someone asked him about it but I have to admit I thought this was going to get to 500 with my ricer math or at least much closer. My LS3 makes 417/424 SAE 5 with tsp headers, ported intake & tb. I figure you gain 35-75hp from cam depending on size; so +40 for this small cam. Holdner tested the TFS 225 heads w/ fast intake on a 6.0L which had stock LS3 heads and intake and gained like 35hp from those. Than there is the point compression bump which should be good for 3-4% in power and bam you're at 500. Point of the story: ricer math doesn't work.
Thread Starter
TECH Enthusiast
Joined: May 2008
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From: Carnation, WA
Several things might affect the number a bit:
-- It’s a Mustang dyno, not a Dynojet.
-- The headers are only 1-3/4" primary (that's all that will fit in my car), and the exhaust is 2-1/2" duals, not 3", again for clearance reasons.
-- The timing is conservative. I told Tom I wasn’t going to run octane booster on the street, just pump 92. It’ll get octane booster when it goes to the track as insurance.
Look at the *very first post on this thread*. I wanted better manners, without giving up power. When I had a choice between street manners (response, fuel economy, etc.) and power, in making decisions on this build, I picked street manners. That's what I asked Tony for, and that's what I got. If I was after power, I wouldn't have pulled the previous cam out.
The car has plenty of power for a Miata. 🙂
-- It’s a Mustang dyno, not a Dynojet.
-- The headers are only 1-3/4" primary (that's all that will fit in my car), and the exhaust is 2-1/2" duals, not 3", again for clearance reasons.
-- The timing is conservative. I told Tom I wasn’t going to run octane booster on the street, just pump 92. It’ll get octane booster when it goes to the track as insurance.
Look at the *very first post on this thread*. I wanted better manners, without giving up power. When I had a choice between street manners (response, fuel economy, etc.) and power, in making decisions on this build, I picked street manners. That's what I asked Tony for, and that's what I got. If I was after power, I wouldn't have pulled the previous cam out.
The car has plenty of power for a Miata. 🙂
Last edited by grubinski; Apr 24, 2021 at 12:21 PM.
Looks like a win from every angle. I have friends that road race Miatas, and they all say the same thing to me...”Miatas are fast around a track, only because they are so underpowered, you just about can’t overdrive them”. I can relate to their thinking, in that when I ran asphalt late models, often times on a short track, slower is faster. Makes no sense to the average reader.
You’ve taken a very docile car and created a rocket ship. I could have some fun with a car like this. I say great job sir. Well done!
You’ve taken a very docile car and created a rocket ship. I could have some fun with a car like this. I say great job sir. Well done!
Thread Starter
TECH Enthusiast
Joined: May 2008
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From: Carnation, WA
I was an MR2 guy for years. My first one, an '86, could be driven around an autocross course with my foot on the floor about 90% of the time. Just turn the wheel, and the car went right where you wanted. When I bought an '88 Supercharged MR2 a few years later, I had to actually respect the throttle pedal. When I tried the "foot on the floor" method at autocross, I left a trail of downed cones in my wake.
This Miata is like that ... times about 100. 🙂
This Miata is like that ... times about 100. 🙂
9 Second Club
Joined: Feb 2004
Posts: 818
Likes: 215
From: VA
Our cams are very similar in spec. The only thing keeping you from near 500 is exhaust. With all due respect I think Tony nailed it for you and your goals. You will be lucky to use 75% of the power in that go kart anyways lol Congrats
Thread Starter
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From: Carnation, WA
Matt Farah reviews an LS3 swapped Miata. This one is about 130 pounds heavier than mine (the Flyin' Miata swaps had AC, P/S, etc. ... this one has ABS, too) and short about 130 horsepower. I obviously don't agree with Matt that 430 horsepower is the perfect amount. :-)
The Miata starts at 6:54 .... the link was supposed to do that for you, but it doesn't for some reason.
The Miata starts at 6:54 .... the link was supposed to do that for you, but it doesn't for some reason.
Last edited by grubinski; Apr 29, 2021 at 08:58 AM.
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Joined: Jul 2020
Posts: 51
Likes: 19
Several things might affect the number a bit:
-- It’s a Mustang dyno, not a Dynojet.
-- The headers are only 1-3/4" primary (that's all that will fit in my car), and the exhaust is 2-1/2" duals, not 3", again for clearance reasons.
-- The timing is conservative. I told Tom I wasn’t going to run octane booster on the street, just pump 92. It’ll get octane booster when it goes to the track as insurance.
Look at the *very first post on this thread*. I wanted better manners, without giving up power. When I had a choice between street manners (response, fuel economy, etc.) and power, in making decisions on this build, I picked street manners. That's what I asked Tony for, and that's what I got. If I was after power, I wouldn't have pulled the previous cam out.
The car has plenty of power for a Miata. 🙂
-- It’s a Mustang dyno, not a Dynojet.
-- The headers are only 1-3/4" primary (that's all that will fit in my car), and the exhaust is 2-1/2" duals, not 3", again for clearance reasons.
-- The timing is conservative. I told Tom I wasn’t going to run octane booster on the street, just pump 92. It’ll get octane booster when it goes to the track as insurance.
Look at the *very first post on this thread*. I wanted better manners, without giving up power. When I had a choice between street manners (response, fuel economy, etc.) and power, in making decisions on this build, I picked street manners. That's what I asked Tony for, and that's what I got. If I was after power, I wouldn't have pulled the previous cam out.
The car has plenty of power for a Miata. 🙂
Cool video btw, seen Farah testing the new body style 525 flying Miata but not this one.
9 Second Club
Joined: Feb 2004
Posts: 818
Likes: 215
From: VA
[QUOTE=dAgent;20348203]No, I get it; I have read this hole thread. You got exactly what you were aiming for and I agree in a Miata it's much more than enough, probably closer to too much power. I was speaking about this head & SBE LS3 combo for my purposes in a LS3 vette that's a 1000lbs heavier. I'm aiming for a throttle response build but also wanto to get to 500 wheel and was hoping this would do it. I don't think 1-7/8" headers and 3" exhaust is going to get me there.
Do you know the difference between 475 - 500 horsepower on the average car at the track? Hundredths if your lucky. You will gain more from rotational weight and proper gearing over 25 wheel horsepower. You can run 11.00 with stock exhaust and good bolt ons in a LS3 vette
Do you know the difference between 475 - 500 horsepower on the average car at the track? Hundredths if your lucky. You will gain more from rotational weight and proper gearing over 25 wheel horsepower. You can run 11.00 with stock exhaust and good bolt ons in a LS3 vette
Staging Lane
Joined: Jul 2020
Posts: 51
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I did, that's an older build and uses stock TSP ported LS3 heads which are probably in the 270-280cc range, not what I would call throttle response friendly.
Staging Lane
Joined: Jul 2020
Posts: 51
Likes: 19
I drove a couple of camed cars in that power range and never liked it. You always loose a bunch of throttle response with anything more than, and including, a medium cam. I want stock like throttle response with 500 wheel, actually more than stock throttle response which my car already has because of the ported intake and tb. I don't care much for the quarter, I like doing road courses, autocross and I drift hence the throttle response.
Thread Starter
TECH Enthusiast
Joined: May 2008
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From: Carnation, WA
I'm betting you could do about the same with untouched stock LS3 heads, just milled for more compression. The extra compression will give you snappier throttle response. And if you don't already have one, a lighter flywheel (not *too* light, but within reason) will also give you better throttle response.
Thread Starter
TECH Enthusiast
Joined: May 2008
Posts: 641
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From: Carnation, WA
Staging Lane
Joined: Jul 2020
Posts: 51
Likes: 19
I'm betting you could do about the same with untouched stock LS3 heads, just milled for more compression. The extra compression will give you snappier throttle response. And if you don't already have one, a lighter flywheel (not *too* light, but within reason) will also give you better throttle response.
I contemplating getting a valve job and milling the stock heads slightly with a gasket and settling for a 465-480 wheel Mavn build with a 224/230 114+3 cam Darth recommended for me; which I like for throttle response or going for the 500 wheel with something like the TSP 255 heads or TEA 255 TFS heads both of which should leave my throttle response in check. I wish I knew for a fact those heads would get me the 20-30 wheel I need which I don't because I've heard it both ways.
Staging Lane
Joined: Jul 2020
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TECH Senior Member
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From: Central Cal.
That's why those who know always say to run it at the track. Times always tell the tale. A dyno number is only good for comparing to another number from the SAME DYNO when mods are made