Reliability on turbo 86

[Irace86.2.0]

Originally Posted by ggiddix

You can get aftermarket Pistons and still maintain 12 to 1 compression

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I think you meant 12.5:1.

I really don't understand the difference between more compression and more boost. 300hp at 10psi at 12.5:1 versus 300hp at 20psi at 10:1 (fake, arbitrary numbers not necessarily reflecting reality), or this idea of needing E85 with high compression low boost, but not with low compression and high boost. If this is true, and if someone wanted to run high boost safely on pump gas then a lower compression may not be a bad idea. Maybe it wouldn't be necessary to run 9:1 compression like an Evo, but 10.5:1 or 11:1 could be considered.

[Irace86.2.0]

Originally Posted by Boris_Petrov

Hello guys, I have thought of puting a turbo on my 86 for a long time and I am keen on the FBM turbo kits. I want my car to be as reliable and as fast as possible. So what do you guys think is the best power range for a reliable turbo FA20 with swapped internals? I'm going to put 9:1 compression ratio pistons.

Any feedback would be really apreciated!

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These two things are mutually exclusive. Either you want to be as fast as possible or you want to be reliable. I understand that you probably meant that you want to add as much power as possible, while not decreasing the reliability to such a low level that the drivetrain is a ticking time bomb. With the said, understand that you are still trading reliability for power. There will be more money needed to maintain the car, more headaches, more wear and tear, etc.

BG...as in Bulgaria? I doubt you have access to E85, so you may want to consider lowering the compression ratio if you are running basic 95-98 RON and you want to hit higher boost.

The stock rods seem to be the weak point. Anything higher than 250-275wtq (which seems to equate to around 350whp) is pushing your luck. Oil starvation can be an issue too. Some have increased the size of their bearing surface-area and/or have done an upgrade to the oil pump. If you are seeing large and/or sustained lateral g's then baffling and other oil upgrades is necessary, as well as, fuel pressure upgrades. If you are doing anything more than a few pulls on the highway then an oil cooling upgrade is necessary like an external oil cooler, and some advise to increase the oil viscosity.

The following also depends on how the car is being used, so yea, anything over 200wtq, and the clutch will need to be upgraded. Anything over 300wtq, and the transmission starts to become a weak link. Some have rebuilt their transmissions with upgraded gears, carbon fiber synchromesh, special metal hardening coatings, etc. Axles are next; I don't know what torque levels they start to go.

[Boris_Petrov]

Originally Posted by Irace86.2.0

These two things are mutually exclusive. Either you want to be as fast as possible or you want to be reliable. I understand that you probably meant that you want to add as much power as possible, while not decreasing the reliability to such a low level that the drivetrain is a ticking time bomb. With the said, understand that you are still trading reliability for power. There will be more money needed to maintain the car, more headaches, more wear and tear, etc.



BG...as in Bulgaria? I doubt you have access to E85, so you may want to consider lowering the compression ratio if you are running basic 95-98 RON and you want to hit higher boost.



The stock rods seem to be the weak point. Anything higher than 250-275wtq (which seems to equate to around 350whp) is pushing your luck. Oil starvation can be an issue too. Some have increased the size of their bearing surface-area and/or have done an upgrade to the oil pump. If you are seeing large and/or sustained lateral g's then baffling and other oil upgrades is necessary, as well as, fuel pressure upgrades. If you are doing anything more than a few pulls on the highway then an oil cooling upgrade is necessary like an external oil cooler, and some advise to increase the oil viscosity.



The following also depends on how the car is being used, so yea, anything over 200wtq, and the clutch will need to be upgraded. Anything over 300wtq, and the transmission starts to become a weak link. Some have rebuilt their transmissions with upgraded gears, carbon fiber synchromesh, special metal hardening coatings, etc. Axles are next; I don't know what torque levels they start to go.

Thanks for the good response, I apreciate it!

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[Boris_Petrov]

@Irace86.2.0 Do you think this might help for the trans problems?
http://www.ft86speedfactory.com/cusc...l#.XCxhEMnRbqA

And by wtq you mean hp or nm?

[ggiddix]

Originally Posted by Boris_Petrov

@Irace86.2.0 Do you think this might help for the trans problems?
http://www.ft86speedfactory.com/cusc...l#.XCxhEMnRbqA

And by wtq you mean hp or nm?

By wtq, he means wheel torque. How much torque the rear wheels are receiving.

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[Boris_Petrov]

Originally Posted by ggiddix

By wtq, he means wheel torque. How much torque the rear wheels are receiving.

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Yeah, but what is it measured by? Nm or foot pounds?

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[ggiddix]

Originally Posted by Boris_Petrov

Yeah, but what is it measured by? Nm or foot pounds?

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Depends where you are located. Here in the states we use foot pounds

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[Hags86]

I debated lowering the compression also but ended up staying and 12.5:1 (with CP Carillo rods and pistons) and I'm so glad that I did.

- Makes crazy power on e85
- Makes great power of 98
- The DI allows you to run much higher static compression than old school wisdom of port injectors only. Compression is free power with lower boost.
- The higher compression makes it feel like a NA car down low. You don't get that big turbo lag.

Here's a thread I started with some good comments.

https://www.ft86club.com/forums/showthread.php?t=127997

[Boris_Petrov]

Originally Posted by Hags86

I debated lowering the compression also but ended up staying and 12.5:1 (with CP Carillo rods and pistons) and I'm so glad that I did.



- Makes crazy power on e85

- Makes great power of 98

- The DI allows you to run much higher static compression than old school wisdom of port injectors only. Compression is free power with lower boost.

- The higher compression makes it feel like a NA car down low. You don't get that big turbo lag.



Here's a thread I started with some good comments.



https://www.ft86club.com/forums/showthread.php?t=127997

Cheers for the feedback! I have actually read this thread already but still thanks!

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[Boris_Petrov]

@Hags86 what power exactly did you make on 98?

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[Hags86]

Originally Posted by Irace86.2.0

I really don't understand the difference between more compression and more boost. 300hp at 10psi at 12.5:1 versus 300hp at 20psi at 10:1 (fake, arbitrary numbers not necessarily reflecting reality), or this idea of needing E85 with high compression low boost, but not with low compression and high boost. If this is true, and if someone wanted to run high boost safely on pump gas then a lower compression may not be a bad idea. Maybe it wouldn't be necessary to run 9:1 compression like an Evo, but 10.5:1 or 11:1 could be considered.

I guess at full revs with the right sized turbo maybe there isn't a difference. But everwhere else in the rev range it makes a difference.
- Low comp = big turbo. So you get a sluggish 9:1 compression before the turbo starts working at say 4000rpm, or
- High comp = small turbo. You get great performance from a 12.5:1 compression and the small turbo starts making boost at say 2500rpm.

The DI covers up for a lot of sins when it comes to detonation which is what allows unheard of 12.5:1 compression before a turbo.

I've also heard that at low compression tuning the DI is a bitch (though I don't have first-hand experience with this).

[Hags86]

Originally Posted by Boris_Petrov

@Hags86 what power exactly did you make on 98?

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All numbers at the wheel on a Mainline dyno
With stock engine.
- 241kW with e85
- 210kW on 98

then after an engine rebuild, keeping the same 12.5:1 and some mild head porting and the same turbo
- 275kW on e85
- haven't dyno'd on 98 with new heads.

[Hags86]

I should update my signature line. That 261kW was on a new engine and we kept the boost/rpm off the limit a bit until the engine was run in.

[Irace86.2.0]

Originally Posted by Boris_Petrov

@Irace86.2.0 Do you think this might help for the trans problems?
http://www.ft86speedfactory.com/cusc...l#.XCxhEMnRbqA

And by wtq you mean hp or nm?

I was quoting rough numbers in torque and not horsepower because torque is what breaks stuff. I was quoting RON instead of our 91 pump, but I forgot to switch to Nm and kW. Sorry for the confusion.

I don’t think the Cusco gears will help. Forth gear seems to give people the biggest problems, not 1st and second. Also, from what I understand, turbos spool up under load, so even though higher rpms have higher loads, shorter gears aren’t advised like they would be for a supercharged or NA car.

I’ve seen dog gears used. Some have swapped a CD009. There isn’t a common solution for the transmission because there isn’t enough demand from tge aftermarket because few are making so much power or tracking their car with enough power to break transmission.