A 4" stroke/6.125 rod is going to give you about 1.115" for the ring stack - not really enough for a high hp turbo setup (in my opinion). I would look for at least 1.2" for the comp height.


Chris

 

What size engines would be a good size.. 375ci iron block, 409ci iron block, or bigger..?

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Pro Stock John:
<strong>


What stroke do some of the turbo race car guys use, like Mike Moran or Lawrence Conley? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">cant really look at them because most racing classes have cubic inch restrictions on turbo cars.

The main thing i look at is mr turbo, kenny duttweiler who has been building turbo/boost motors for years and years. He likes to stick with the classic 377 combo (4.125" bore and standard 3.48" sbc stroke)

 

very good explanation....but it is still my "opinion" that when setup correctly a big bore is the way to go.

Also...look at some bigger inch FI motors compared to smaller inch FI motors and you will see the difference in torque that i am talking about

 

Thanks ChrisB, that's why I am selling the crank I have now, I can't get down to 8.5:1 with that stroke. I am going to run a stock 3.622 crank at this point but for laughs I might try to source a 4.8 crank.

Well if I went with a 2.02 intake and not a 2.05 intake, I am giving up like 10 cfm is that going to be a big deal? I don't have a handle on the relationship between FI and port velocity. Any books you folks reccomend reading?

 

your entering into another dimension now John.do do ..do do.
You need to take off your N.A. hat now. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

your cfm rate into the motor is fixed by the turbo.

You can play with valve sizes or add a few cubes,
And that have some minor effects.
But it's all going to come down to how much air you let the turbo flow into the motor.


You just pump it in until you get to where you want to be. Just slap a nice strong motor together with decent heads and a decent cam for a turbo.
Start really thinking about your fuel system, tuning and especially everything related to detonation control.
Steve

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by SJH:
<strong>But it's all going to come down to how much air you let the turbo flow into the motor.
</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Can you elaborate?

I am planning to run a fuel system that is a blend of what Matt Harlan and a 154mph Mustang friend (Renegade Mustang) are running...

 

What's the BSFC of your Mustang friends motor?
What does he use to tune it? What size injectors does your friend use?

Honestly if you have a friend that runs that MPH you should really look closely at that setup.

Does your friend tune it himself? Does he hire seomeone to be at the track? What are your thoughts on tuning for your setup?

What are your HP goals? Do you think that your existing suspension will be good enough given the HP and TQ increases?

All of this plays into a good design of the motor also. What will you use for boost control?

 

I get it now.. Thanks guys..

 

I should have read more before posting my "new" idea thread, you guys already cover these turbo V8 limit topics

I guess all I have to do now is figure the car chassis I'm gonna use...

 

Chasgiv3,

He said he uses 83lb injectors. It's a supercharged Mustang. He made 750rwhp, and at 3300 raceweight he went 150 mph. He figures he was making 790rwhp when he went 154mph. Renegade cars are pretty dialed in, they can only go so far and stay within the class rules. His motor is only like a 4.030 x 3.000 to fit in the class he races. His best time is 8.97 @ 154mph. Hope that info helps some of the folks who are seeking 8's in 2003.

 

John...I admire your quest for FI power...however, dont skimp. At the very least, have Harlan/Detroit Speedworks tune the car with Harlan's converter for low-z injectors. And use a bad to the bone Weldon pump with a stepdown. If i was in your position given what you run now...I dont see anything smaller than a T-76 single (and hopefully more like an PTE-88) going in. Also, skip that air-to-air non-sense and go with a water/air mounted where-ever with a tank and pump in the rear. I mean, you run 11.0's now ?? if 9's are the goal...your looking at this the wrong way.

Ryan

 

I would spend some time investigating on how to keep the heads from warping. After reading some of Rob Raymers old post. This seems to be the problem. I think a iron block with all the goodies would hold up just fine, but our weak/thin head design is the weak link.. Ford guys are running around with 30#'s of boost and can easily run 20#'s with proper tuning on pump gas.. There head design is better than ours when it comes to how much material is on the aluminum head.. Hint, hint..

 

To run 8's at let's say 3400 lbs race weight. Would take some 925RWHP or 1101FWHP assuming 16% losses.

Injectors sizing formula states that you should run 86.02 lb/hr injectors at 43.5PSI with a BSFC of .50 and a duty cycle of 80%.

If you switch to a 58PSI fuel pressure baseline then you need an injector size of 65lb/hr.

Those seeking 8's should calculate:
1. fuel line and pump requirements based on HP requirement
2. Air Flow requirements based on max HP required
3. Turbo(s) to support those Airflow requirements under the desired boost range using the manufacturer supplied compressor maps.

Chassis tuning is something that I just don't have a clue about. That'll be something I'll try to figure out this year or borrow from someone who already has it figured out.

 

From what I am hearing 800rwhp might be good for very high 8's, I would think that 925rwhp would be good for mid 8's?

 

For 700RWHP you could go stock bore and stock stroke. It's already been done by Harlan.

Safest bet is to go 6.0 liter iron block unless your trying to prove a point or you absolutely need the weight savings.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by chasgiv3:
<strong> What's the BSFC of your Mustang friends motor?
--dunno

What does he use to tune it?
-->limited to stock pcm and a pmc or something like that it some sort of extender? He's class limited.

What size injectors does your friend use?
-->I think they are 83's but I'll check.

Honestly if you have a friend that runs that MPH you should really look closely at that setup.

Does your friend tune it himself?
-->Yes a lot of dyno pulls.

Does he hire seomeone to be at the track?
-->No

What are your thoughts on tuning for your setup?
-->I'm thinking using stock pcm + lo-z box.

What are your HP goals?
-->725rwhp

Do you think that your existing suspension will be good enough given the HP and TQ increases?
-->Everything on my car will work except the torque arm. I'll probably have a custom bracket made and keep the R/T but I have to have it mount to the crossmember.

All of this plays into a good design of the motor also. What will you use for boost control?
-->no idea </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">

 

John,
ChrisB already went into some detail about the turbo/blower controlling the cfm or lbs/min of air rate into the motor.
The motor does not breath on it's own anymore.
This is what forced induction is all about.
"FORCED". That's the word you need to stamp in your mind.
Hey if you have the budget , then do the best of everything.
Nothing wrong with that and it will make hitting your number easier.

But a decent 346 with enough boost is going to crack your number no problems.
Looks Like Harlan already did it.
If somebody could tune good enough and keep the heads sealing, you could make 1000 hp with stock heads and cam if you "force" enough air into the motor.
Take the pro 4cyl example above.
1000hp!@ It's a T76. Only 4cyls, small valves etc. It takes 29psi of pressure to force enough air into the motor though.
It might take only 15psi on a built 422 with serious heads.
But the airflow into the motor would be about the same.
Put aside enough budget for engine repairs.
There is usually a few mishaps along the way as you learn your new poweradder. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Steve

 

I checked my math and it seems right.

So real world guys are running 8.99 or better with 800RWHP at 3400 race weight?

 

I think that the 6.0 heads have more meat then the 5.7's.
Hopefully that will stop head warping.

IF that doesnt work, looks like you'll have to weld some braces on you heads to stop warping.