So. Thought exercise at the moment. Kinda.
Id love to get quicker spool out of my turbo miata that im doing for the challenge. Better throttle response. More midrange. More power out of the slower corners.
What contributes to quicker spool and power under the curve in a turbo car?
Its a Garrett 2560r, 2.5 downpipe and catted exhaust, running on stock ecu woth an aem fic-6 piggyback through a 6 speed and 3.90 gears.
Annnndddd.....
GO!
My answer to that same problem was 3" from the turbo back.
On my BP4W, It spools as fast as my old 2554R that I had on a previous car. I also run a pretty aggressive spark curve on my "full boogie" tune. That just took it to the next level. I'm happy as can be with the way it runs.
Challenge budget? Windshield wiper fluid activated by a micro switch on the throttle. You should have about all you need already in budget by repurposing your current windshield wiper bottle and pump. Make sure you use the really good cold climate stuff.
Do you mind backfiring? Or since this is a challenge car, don't worry about exhaust temps? Instead of turning the fuel off on deceleration, keep it on, but spark so late that the heat is moved into the exhaust to keep the turbo spinning.
Lift and duration
In reply to Dusterbd13-michael :
I had trouble keeping traction with a full Flyin Miata turbo setup, and it actually made it too easy to overdrive. That was with 15x9s and rt660s. Have you had a chance to run it at an autocross yet to see if you need the extra spool or torque?
In reply to captainawesome :
Nope! Just around the neighborhood still installed in the parts car. Not even making full boost, limited to 10psi.
15x8 on 200tw 225s is the plan.
Im trying to optimize as i build, instead of having a bunch of rework. I may not need to, but....
Advance the intake cam a bit?
Sounds like nothing a little 50 shot couldn't fix
So far I've seen three inch exhaust, water and meth injection is the two early interesting suggestions that fit my long-term goals and challenge plans. What about things like porting and the bigger throttle body and bigger air filter and such? What other factors affect turbo spool time and power under the Curve? I'm a total newbie when it comes to turbo cars
Boost control - what are you running? A ball and spring valve ("Grainger valve") to the wastegate actuator can be helpful, the idea being that the wastegate stays closed up to a certain point, instead of (possibly) gradually opening as pressure ramps up.
In reply to Nathan JansenvanDoorn :
At the moment I am just running vacuum to the stock Garrett wastegate. However when it gets installed into the good car I have a full Blitz electronic boost controller that has a solenoid that goes in place in between the vacuum source and the stock waste gate to dial in the desired amount of boost
3" exhaust/downpipe. Depending on the cat, you might want to lose that.
Manual boost control if you're running wastegate pressure. That's by far the easiest, it'll give a bunch more area under the curve.
E85 and a E36 M3load of timing.
Dusterbd13-michael said:So far I've seen three inch exhaust, water and meth injection is the two early interesting suggestions that fit my long-term goals and challenge plans. What about things like porting and the bigger throttle body and bigger air filter and such? What other factors affect turbo spool time and power under the Curve? I'm a total newbie when it comes to turbo cars
Throttle body isn't likely to make much difference, the intake air is compressed already by the time it gets to the throttle. Bigger air filter depends on how big it is already :) We don't need to go to the Fast and Furious era dimensions ,especially not for 10 psi.
Improving flow through the head is high effort but will help. Not as much as that boost controller or exhaust size.
Propane and propane accessories?
Keith Tanner said:Dusterbd13-michael said:So far I've seen three inch exhaust, water and meth injection is the two early interesting suggestions that fit my long-term goals and challenge plans. What about things like porting and the bigger throttle body and bigger air filter and such? What other factors affect turbo spool time and power under the Curve? I'm a total newbie when it comes to turbo cars
Throttle body isn't likely to make much difference, the intake air is compressed already by the time it gets to the throttle. Bigger air filter depends on how big it is already :) We don't need to go to the Fast and Furious era dimensions.
Improving flow through the head is high effort but will help. Not as much as that boost controller or exhaust size.
How much boost are you running?
8-10 psi on the wastegate according to the gauge. Po stated it was 14-15 before he wrecked it. I bashed it back together to make sure everything is healthy before stuffing into the challenge car
Retard the timing via a ECU rewrite. Smaller ar exhaust turbine housing. It's a challenge car, what exhaust? Nitrous.
Goodness gracious :)
Well, that air filter is big enough. Getting rid of restriction behind that turbo (you can keep the turbine outlet, it'll be okay) will be an easy option. So will the boost controller. Run as much octane and timing as you can. Shave the head to get more compression - you'll trade off peak power for that but you'll gain response.
Edit - I think you want lots of timing to spool. I'll check with my tuning wizard.
For those suggesting nitrous note that Michael mentioned more mid-range and coming out of corners faster. Then note this rule:
Nitrous use is not allowed during the autocross. Nitrous bottles are not allowed in cars during the autocross.
Hopefully he won't have any corners in the drags.
The current tuning setup has limited options. The AEM FIC he's running can retard timing but not advance it. I can't remember if it can subtract fuel or only add it. And there's not much you can do inside an NA Miata ECU.
One questionable idea that came to mind is plumbing a CO2 tank into the exhaust manifold. Trigger it when you're at full throttle and not enough boost by using a throttle micro switch and a pressure switch.
Advancing the intake cam one tooth (~8 degrees) is free... 
I have linked this before, don't remember where. You don't have VVT to play with BUT you can see the effect intake cam timing has on boost onset RPM as well as the effect it has on midrange torque with a given amount of boost.
And it's free
MadScientistMatt said:The current tuning setup has limited options. The AEM FIC he's running can retard timing but not advance it. I can't remember if it can subtract fuel or only add it. And there's not much you can do inside an NA Miata ECU.
One questionable idea that came to mind is plumbing a CO2 tank into the exhaust manifold. Trigger it when you're at full throttle and not enough boost by using a throttle micro switch and a pressure switch.
So I also have a megasquirt to Plug and Play in The Challenge bucket. However after previous experiences with mega squirt I am very very gun shy about using it. I have not had good megas work experience. I'd also want to get it checked out prior to trying to run it as to my knowledge the previous owner hadn't used it it was included in the car when he got it. It's supposedly tuned for 14 or 15 pounds and 250 horsepower on this car. This car being the 99 engine and Chassis.
Keith Tanner said:Improving flow through the head
Lift and duration.
Replacing the stock cams is usually over looked in a turbo installation but should be the first thing you do. Other than increasing boost nothing will work better on a turbo car to make reliable power.
hater pipe out the hood (also the name of my Sophomore album).
NVM, just saw the photo, no hood necessary.
Lots of good advice above. I'll add wrapping the exhaust manifold/turbine housing- heat lost is not driving the turbine. Also check the transition from the manifold to the turbine housing and make sure it's smooth with no step. Make sure the wastegate flapper is centered over the hole and seals well. You can shim the wastegate actuator to increase the spring pressure. This will raise your minimum boost, and seal the wastegate better for longer, even with a good boost controller. Boost pressure on the actuator isn't the only thing that opens the wastegate, it's also got exhaust gas pressure pushing against it. Add some washers under mounting points until boost raises to 12psi or so on the wastegate, then add the boost controller.
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