Ok, so my questions are:

-What do you consider to be a safe boost level for E85 for roadracing in say 80-100F track temps on a BUILT 2.0L Stock Frame Turbo (CBRD BBK-Full)? Is 26-27psi about right? Running all session long.

-What do you consider to be an aggressive boost level for E85 for roadracing in say 80-100F on a BUILT 2.0L Stock Frame Turbo (CBRD BBK-Full)? Is 29psi about right for 1 or 2 hot laps per session.


Please answer if you have first hand road race experience and not friend of a friends brother story.

Mods in signature. Same with power/torque etc..

Thanks!

 

Bump! I would like to know as well

 

So the big question you need to ask yourself is how much power do you need for road racing. When I road racing I target 22psi on E85 and about 330whp. Anymore power than that is beyond my suspension and exp level.

I daily drive my evo on 28-29psi in full kill mode. I beat my car pretty bad while driving it. But for road racing I just do not need that much power.

So to answer your question, you can run 30psi all day long for road racing, you just nee to make sure that your tune supports the elevated engine/intake temps. Run a richer afr like 11.5 instead of 12.0-12.5. Pull the timing down just a bit to keep cyl pressure down. The biggest thing is to do a holt lap while datalogging and see what is going on with your car.

 

Thanks for your reply. I think I just need more torque. I am pretty comfortable with my current setup. 450whp/400wtq (low reading Mustang Dyno) would be perfect. At the same time I think it would be more fun to run 3-4 hot laps instead of 1 or 2 hot laps do a cool down lap and do another 1-2 laps then come in. So yes, the tune and everything has to handle the elevated engine temps, water temps, intake temps, heat, etc. Yeah, I should datalog my car while tracking. Then again I still need a 4bar map sensor. Also need to figure out a way to secure laptop so its not sliding bouncing all over the place. Im sure its not good for the moving parts in the hard drive.

Bump for more input.

 

I run 26 psi on my stock block with cut 93/100 octane gas for road racing with a BBK Full. I haven't experienced any problems running hard all session so far, but when I go to E85 I'll probably go slightly more aggressive. If you are comfortable with the power you have and just are concerned about the safety of the motor you should be well in safety limits at those boost pressures depending on timing and ambient temps. A built motor on E85 can take a complete pounding, and I wouldn't imagine 29 psi is going to cause any problems even for full sessions at WOT.

 

Thanks for sharing. Good to know that a built motor with E85 can handle 29psi on stock frame turbo all session long. Good news indeed.

 

I run 25-26psi on my stock block Zhong

 

You are mad to run 29psi on the stock block with a turbo that can hold it (key point here) at the actual race track (with turns)...

A stock 9 turbo isn't anywhere close the same air flow as the BBK Full.

29 psi spikes for 100rpm from the 9 turbo I can see but extended 29psi is asking for trouble.

On a built block I would also use a different strategy as a stock frame turbo like that will still be asking for trouble from holding a bunch of boost lap after lap.

If you hate your turbo or car, then go for it.

 

I wouldn't run 29 psi on the stock turbo period, let alone for road racing, but the BBK Full with E85 can handle 29 psi. The main issues to be concerned with are detonation and excessive torque causing damage to the bottom end. Especially for the stock block guys like myself. I keep my tune conservative on the torque side to preserve the motor, and run a high enough octane to prevent detonation at my boost level (26 psi on cut fuel).

As long as the turbo is being run inside its efficiency range and isn't generating tremendous amounts of excess heat, there should be no problem running a stock frame turbo for road racing.

 

I guess you haven't see enough melted turbine wheels yet then...

 

So Bryan, what would you consider safe and aggressive boost levels for E85 on built block with cbrd bbk full for road racing?

 

Bryan is a tuner by profession who actually road races too. Maybe you should seek his consulting/tuning services.

This is a good question, btw.

 

If you aren't overspinning the turbo or running it outside of its efficiency range why would the turbine wheel be melting? I'm not the expert especially when it comes to E85, but I'm running 26 psi on cut gas right now with no problems, so I'm trying to understand what you feel would cause failures.

I'm also curious why you feel that a stock frame turbo is inherently less capable of handling road racing conditions. From what I understand, if a stock frame turbo and a t3 turbo are both run in their efficiency range at appropriate boost levels for the fuel the differences between the turbo/manifold should not cause premature turbo or engine failures.

 

The stock housing creates a bunch of back pressure when you cram larger wheels not designed for it.

That is the major difference between the stock frame turbos and a "proper" larger turbo.

I've done a ton of logging and tuning for track Evos in all sorts of different conditions, a bunch that have been Nasa Time Trial champions that also have broken track records. Also a bunch of Time Attack Evos on a bunch of different continents. I've seen alot of equipment failures from the heat and demands that track driving creates. These weren't Evos that only see the track a couple of days a year.

While It might sound like I'm bragging with the above, it couldn't be further from my actual intention. I'm just sharing knowledge that I have acquired from experience.

With a BBK Full, and a proper upgraded cooling systems on the car (Water, Oil, Air) I'd personally set it at 26 or so PSI across the rev range and you should be able to beat the day lights out of it every event with no issues. E85 will create a great amount of power over pump gas even at what might seem to others, a "low" boost pressure on E85.

Now, on shorter tracks with lower overall high-gear WOT or at shorter events like a Time Attack where you really just need a good flyer lap, you can set it a bit more aggressive.

 

Hmm, very interesting information. I didn't realize the stock frame turbos were creating that much additional back pressure even running at an appropriate pressure. That may make me re-think my long term strategies for turbochargers. Right now the BBK Full produces a good amount of power for my skill and aero, with minimal lag, but the car is really being built soley for road racing. That being the case, I assume you prefer a tubular manifold and a "proper" ball bearing T3 style turbo? What size and power levels are being used for the time attack champions?

I have all of my cooling systems upgraded including oil cooler, radiator, and intercooler, which may be a contributing factor to why I've experienced no real hiccups at my current 26 psi. As I'm making the change to E85 and freeing up some exhaust flow I guess I can keep the boost the same with a better fuel.