Talk me into a centrifugal

[NightmareMoon]

Car is 40% street, 50% autocross, and 10% track.

I have to rebuild (or part out) this Gen2 motor, so I need to decide on boost and choose a 9.5:1 compression motor or a 12:1 NA optimized motor.

I've had great results with this as an NA build, but I want more power/torque, and for reasons I want to lower the diff ratio to get a higher top speed in 2nd gear, which implies going from 3.73s to 3.31s and therefore losing torque in the process.

I had a smaller 1.8l turbo sports car in the past and loved the turbocharger's personality, but it looks like the spool time for these V8s from a lower RPM is too long for my autocross habits. Plus the weight of system. This car turns corners so weight is the enemy. I wish there was a turbo kit optimized for hyper fast spooling at the expense of top end power. ~600-650 at the wheels is my goal, I don't need 800 to race around parking lots with cones.. even big parking lots.

So I'm considering the ESS or P1X.

While it sounds like a bad idea for a track car. I'm willing to duct and upgrade the radiator to help with heat and I think its probably ok to get just a couple hot laps before cooldown laps in between. I like to get on track a few times a year, but I don't need to run 30 minute sessions or anything to enjoy myself.

I'm still on stock MT86 and axles, so I hope those can hold up for a while. I'm kind to things when launching but we do run hard.

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[Brevin]

Car is 40% street, 50% autocross, and 10% track.

I have to rebuild (or part out) this Gen2 motor, so I need to decide on boost and choose a 9.5:1 compression motor or a 12:1 NA optimized motor.

I've had great results with this as an NA build, but I want more power/torque, and for reasons I want to lower the diff ratio to get a higher top speed in 2nd gear, which implies going from 3.73s to 3.31s and therefore losing torque in the process.

I had a smaller 1.8l turbo sports car in the past and loved the turbocharger's personality, but it looks like the spool time for these V8s from a lower RPM is too long for my autocross habits. Plus the weight of system. This car turns corners so weight is the enemy. I wish there was a turbo kit optimized for hyper fast spooling at the expense of top end power. ~600-650 at the wheels is my goal, I don't need 800 to race around parking lots with cones.. even big parking lots.

So I'm considering the ESS or P1X.

While it sounds like a bad idea for a track car. I'm willing to duct and upgrade the radiator to help with heat and I think its probably ok to get just a couple hot laps before cooldown laps in between. I like to get on track a few times a year, but I don't need to run 30 minute sessions or anything to enjoy myself.

I'm still on stock MT86 and axles, so I hope those can hold up for a while. I'm kind to things when launching but we do run hard.

ESS G3 with G4 intercooler upgrade and an 11:1 motor would be my suggestion. Helped out quite a few auto cross guys with that setup over the years and had great success. Feel free to PM me if you have any questions on the ESS stuff

 

[K4fxd]

I'd keep your 9.5 comp ratio. It will be a TON easier on parts and less sensitive to octane. You will easily make the power you want with 9.5.

 

[black22gt]

Full disclosure, I'm not going to be boosting my car anytime soon, so grain of salt.

But if i did, a centri is my preferred for one simple reason: I want a boost control kit, so i can dial up the boost when i actually need it, and I dont think any other belt driven superchargers do that (turbos can though). Could be wrong. In my head, its kinda like a NOS button but permanent so you dont have to refill a bottle.

Just my thoughts, it'll be many moons before i will be able to test this for myself.

 

[blakeman8192]

The power delivery of a centri is a lot like an NA motor, just on steroids. It drives similar to stock in the low end, then really gives you the beans when you decide to open it up. They give you power predictably without lag (unlike a turbo), just downshift and go. And they don't create unusable gobs of torque in the low end that stresses components, shreds tires, and ruins launches on unprepped surfaces (like PD blowers do).

Mine drives like stock under 2500RPM, has a noticeable torque bump at 3k, starts pulling pretty hard at 3500-4k, and redline happens VERY quickly after that.

Intake air temps are generally excellent thanks to being able to run an intercooler, mine are always no more than 5-6 degrees above ambient. And with ESS, heat soak is almost never a problem because it's positioned pretty far away from the engine.

It's just a good, well-balanced approach to adding power that doesn't cost you $10k+, and can be self-installed in a day even if you don't have a lot of mechanical experience. Plus it sounds like you're driving a fucking jet down the road and you get the addictive BOV noises. The sound alone breaks necks rolling through town.

 

[MrMike]

I am loving the slippery slope of this rebuild. I hope it comes with lots of pics.

 

[Pistol_91]

The power delivery of a centri is a lot like an NA motor, just on steroids. It drives similar to stock in the low end, then really gives you the beans when you decide to open it up. They give you power predictably without lag (unlike a turbo), just downshift and go. And they don't create unusable gobs of torque in the low end that stresses components, shreds tires, and ruins launches on unprepped surfaces (like PD blowers do).

Mine drives like stock under 2500RPM, has a noticeable torque bump at 3k, starts pulling pretty hard at 3500-4k, and redline happens VERY quickly after that.

Intake air temps are generally excellent thanks to being able to run an intercooler, mine are always no more than 5-6 degrees above ambient. And with ESS, heat soak is almost never a problem because it's positioned pretty far away from the engine.

It's just a good, well-balanced approach to adding power that doesn't cost you $10k+, and can be self-installed in a day even if you don't have a lot of mechanical experience. Plus it sounds like you're driving a fucking jet down the road and you get the addictive BOV noises. The sound alone breaks necks rolling through town.

This..... All this

 

[80FoxCoupe]

The power delivery of a centri is a lot like an NA motor, just on steroids. It drives similar to stock in the low end, then really gives you the beans when you decide to open it up. They give you power predictably without lag (unlike a turbo), just downshift and go. And they don't create unusable gobs of torque in the low end that stresses components, shreds tires, and ruins launches on unprepped surfaces (like PD blowers do).

Mine drives like stock under 2500RPM, has a noticeable torque bump at 3k, starts pulling pretty hard at 3500-4k, and redline happens VERY quickly after that.

Intake air temps are generally excellent thanks to being able to run an intercooler, mine are always no more than 5-6 degrees above ambient. And with ESS, heat soak is almost never a problem because it's positioned pretty far away from the engine.

It's just a good, well-balanced approach to adding power that doesn't cost you $10k+, and can be self-installed in a day even if you don't have a lot of mechanical experience. Plus it sounds like you're driving a fucking jet down the road and you get the addictive BOV noises. The sound alone breaks necks rolling through town.

Post a log that shows iat that is 5-6deg obove ambient on a full pass.

 

[engineermike]

Post a log that shows iat that is 5-6deg obove ambient on a full pass.

You probably know this but I’ve compared logs of PD vs centrif/turbo charge temps. The PD water/air usually starts out warmer than ambient but the charge temps holds very flat over the course of a quarter mile. Centrif/turbo air/air starts out at ambient or close to it but heats up very quickly and by the end of the quarter is quite hot.

 

[80FoxCoupe]

You probably know this but I’ve compared logs of PD vs centrif/turbo charge temps. The PD water/air usually starts out warmer than ambient but the charge temps holds very flat over the course of a quarter mile. Centrif/turbo air/air starts out at ambient or close to it but heats up very quickly and by the end of the quarter is quite hot.

Absolutely. Folks with a2a intercoolers that don't race, usually state misleading iat numbers. Does his log show 5-6deg over ambient cruising? Sure. Does it show the same value on a 2sec teeny tiny wot hit? Sure. Does it show that value on a quarter mile pass? Absolutely not.

So when op reads that dudes ess kit can produce such low iat numbers cause it's efficiency defies the laws of physics, the op has been mislead.

 

[robvas]

I've had great results with this as an NA build, but I want more power/torque, and for reasons I want to lower the diff ratio to get a higher top speed in 2nd gear, which implies going from 3.73s to 3.31s and therefore losing torque in the process.

I had a smaller 1.8l turbo sports car in the past and loved the turbocharger's personality, but it looks like the spool time for these V8s from a lower RPM is too long for my autocross habits.

I wish there was a turbo kit optimized for hyper fast spooling at the expense of top end power. ~600-650 at the wheels is my goal, I don't need 800 to race around parking lots with cones.. even big parking lots.

So I'm considering the ESS or P1X.

I'll try to talk you out of it, for your particular case.

Centrifugals like gear. They like the 10 speed auto. But, they aren't as 'weak' at say, 5,000 RPM as some people might believe.

The last thing you want to do take gear away on a stick centrifugal car. At least you could put a torque converter in an automatic and fix the low RPM issues.

I'd put money on the base turbo kit from whoever making power 1,000 rpm earlier than any centri. You can try to use those 'torque booster' setups but you honestly aren't going to spin the thing fast enough to make a large amount of power down low, and if you did, it'd be so out of the efficiency range on the high end...

If you look at the dynos they don't really add anything noticeable up until 5,000+ anyway.

 

[80FoxCoupe]

I'll try to talk you out of it

Centrifugals like gear. They like the 10 speed auto. But, they aren't as 'weak' at say, 5,000 RPM as some people might believe.

The last thing you want to do take gear away on a stick centrifugal car. At least you could put a torque converter in an automatic and fix the low RPM issues.

I'd put money on the base turbo kit from whoever making power 1,000 rpm earlier than any centri. You can try to use those 'torque booster' setups but you honestly aren't going to spin the thing fast enough to make a large amount of power down low, and if you did, it'd be so out of the efficiency range on the high end...

If you look at the dynos they don't really add anything noticeable up until 5,000+ anyway.

Centri not making any noticeable power till 5k rpm is a weak ass setup.

 

[robvas]

Centri not making any noticeable power till 5k rpm is a weak ass setup.

talking about the torque booster adding more power compared to without

This graph for example...like 10hp at 4k but like 70 at 5k. Nice boost but it doesn't really fatten the low end up like OP wants

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