5.73@122.1 DRW/Buick new best.

[DonWG]

An interesting tuning note.
Methanol boils at 149 F at standard atmospheric pressure. The boiling point is higher with higher pressures. To obtain proper vaporization of methanol for proper combustion, I would suggest that it's important to maintain a certain temperature window in the intake, during compression and combustion. The temperature in the cylinder being dependant on factors such as cylinder temperature (engine temp), static CR level, and intake charge boost level and starting temperature. The circumstances of maintaining this temperature window would change with more demanding tuneups, such as the degree of aftercooling and the amount of extra fuel that would be used strictly for the purpose of cooling. The main concern being to keep the fuel away from detonation/pre-ignition limits.
The amount of vaporization that would need to occur in the intake, during the compression stroke and during combustion is still a mystery to me. I'm sure that the vaporization levels at these different stages would be closely tied to the demands of the tuneup (target horsepower).

I don't know how I get into these long hair sessions. Good grief.

[John Wilde]

Originally Posted by DonWG

You know, the more research I do, the more I feel that a T4 turbine housing is going to be too restrictive for a 1,230hp target. Is this the popular concensus with the rest of you?

On your new turbo I would do a T6 especially on a alky motor.
Please keep in mind you will need more turbine wheel and housing than a gas motor. With the launch assistance you really have no good reason to retain the T4 flange IMO.

[DonWG]

Originally Posted by John Wilde

On your new turbo I would do a T6 especially on a alky motor.
Please keep in mind you will need more turbine wheel and housing than a gas motor. With the launch assistance you really have no good reason to retain the T4 flange IMO.

X2! That is exactly my thinking too. The products of combustion level is higher with an alcohol engine. The T4 housing would just back up easier than it would with gasoline. And the point of the launch assist is well taken. Spoolup time is not a concern with me. It's handled.
I want a housing that is less targeting spool up time and more targeting max hp at max rpm.

[DonWG]

John, what would be your suggestion on the a/r.

[John Wilde]

for the GT47 you have two choices (from precision's price list) the .96 and 1.08, I would go with the 1.08 for sure, even bigger if they make one that is not on the list!

[DonWG]

If you're familiar with both, I'd like a suggestion for each. I'm sure you're familiar with the GT4788. Do you have any experience with the S480?

[DonWG]

Oh Norb, the ambient temps were not extreme if I remember correctly. Mid 70s.

[John Wilde]

Originally Posted by DonWG

If you're familiar with both, I'd like a suggestion for each. I'm sure you're familiar with the GT4788. Do you have any experience with the S480?

I don't but Dusty does, a friend of his has one on a V8.
You may want to hit up Jose at forecedinductions on the BW stuff.
He seems to be the most knowledgeable person I know of with them.

[DonWG]

Thanks John. I value your opinions very much.

[John Wilde]

Originally Posted by DonWG

Thanks John. I value your opinions very much.

Thanks man, my wife loves San Diego, want to give me a job?

[DonWG]

Hey, if I had enough work flow for ya, it wouldn't be a problem. You're hired.

[lazaris]

Don the issue you talked about with the adjustment on the gate is showing that the BP is causing it to push open. As far as a T-6 or T-4 I believe Ted is still using a T-4 on his 47-88. Hes well in the mid 8's. I think you can go pretty far on a T-4 with a 224 cu in's with the right turbine wheel and exh housing. Thats why a BP reading would really help you.

[Cheeseburger]

Very immpressive, always like watching your car videos too!

[John Wilde]

Originally Posted by lazaris

Don the issue you talked about with the adjustment on the gate is showing that the BP is causing it to push open. As far as a T-6 or T-4 I believe Ted is still using a T-4 on his 47-88. Hes well in the mid 8's. I think you can go pretty far on a T-4 with a 224 cu in's with the right turbine wheel and exh housing. Thats why a BP reading would really help you.

Ted is not running a alky motor it is not a fair comparison.
Alky turbo motors need much more breathing on the turbine side.
Ask Garrett, Precision, Turbonetics or any of the companies supporting
alky drag cars. For Don's application there is no downside for a T6 Flange.
However this does not mean it would not work with a BIG T4.

[John Wilde]

BTW: My response sounds jerky, but it is not meant to be. Sorry Laz...
The flu and ear infection are killing me.

[DonWG]

I really appreciate the feedback on this. All points are valid. I'm pumped up now. I'll get that back pressure reading first before I do anything else. That should be on the 22nd or earlier if something is going on at Barona before then. Thanks again, everyone.

[lazaris]

Originally Posted by John Wilde

BTW: My response sounds jerky, but it is not meant to be. Sorry Laz...
The flu and ear infection are killing me.

Not taken as jerky. I'll also point out that Ted's car has about 50 more cubic inches on Don's. This in itself requires more exhaust flow as compared to the smaller motor. So you must take this into consideration as well. I'm sure either Flange can be made to work. The T-4 will just incur less work for Don.

[DonWG]

Originally Posted by Cheeseburger

Very immpressive, always like watching your car videos too!

Thanks Cheeseburger. It's always nice to know the effort's are being enjoyed by others.

[bison]

My guess on the backpressure is 48psig at 32 psig intake pressure. Id run the t6 flange with as big an a/r as you can stand. Just increase the N2O on spoolup to take care of the spool. If you go really large ont he compressor you may need to change cams but the head flow will be choking you for sure if you did that. Id just look for more exhaust wheel and housing flow. There is probably 80-100hp in just that.We will see after you post the bp number. Your mph should shoot up a lot. That old 76Q is being worked pretty hard.

[DonWG]

Remember, I'm not even using the max (29.9 psi) spring package in the wastegate AND it's cracking open. To me that makes me think it's a relatively lower bp. It's fun guessing on this.

Bison, I appreciate the advice. I'm already using a pretty big shhtick in the motor. A lot bigger than everyone would think is needed. I originally spec'ed the cam to make up for the deficiencies of the heads and make the most of them as they were. Granted, the target hp level back at the beginning was around 800 hp, not 935, and certainly not 1234. Gosh, I'm still running the original 1.835 int. and 1.5 exh. valve sizes.

I calculate I'm pumping about 84 lb/min airflow. Real close to the limit for the T76, but not quite over it. For those getting their calculators out, that's 11.1 hp per lb/min airflow. I'm getting about 10% more hp for each lb/min airflow because of the methanol.

I can verify that the engine simulation software I use has been right on, up to this point.