Cummins Twin turbo ISB 3.9

Forrest Nearing said:
I would definately run a P-pump, and I would plan on running a dry-sump setup to help get the engine low in the chassis.

if you've got unlimited budget, I'd go with a build Duramax, personally... better powerband, lower center of gravity, etc.
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All very true... I wonder, though, if he has a cubic inch limit to worry about??? Though I would think that not only being beat by a diesel, but an I4 would be rather insulting. I see a lot of new rules being written after he gets it together :doh: :hehe:
 
There is no engine size limit for a 4 cylinder, and I have wondered about other competitors reaction to having their arses whipped by a diesel, and a 4 cyl to boot. But having raced the class for about 9 years, I know that the V8's would not match a well set up twin turbo 4b-t off the turns. No way. And that is where the races are won and lost. Plus 4b-t at 800 ft/lb, V8 at 425 ft/lb. No contest.
 
The V8's are allowed to run on petrol or methanol, but they have a 11-1 comp rule, and must use standard type iron heads, (Porting and polishing is allowed) but they are limited to 1 x 4 barrel carburettor, so the good motors are making about 550 - 575HP. But everyone knows that torque is what gets you off the turns and hauls you down the straightaway. I think the 4B-T will win out over the V8's since it will build torque quicker that a V8, and ultimately will have approx double the torque of a V8 when maxed out!
 
4B-T said:
The V8's are allowed to run on petrol or methanol, but they have a 11-1 comp rule, and must use standard type iron heads, (Porting and polishing is allowed) but they are limited to 1 x 4 barrel carburettor, so the good motors are making about 550 - 575HP. But everyone knows that torque is what gets you off the turns and hauls you down the straightaway. I think the 4B-T will win out over the V8's since it will build torque quicker that a V8, and ultimately will have approx double the torque of a V8 when maxed out!
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I know what you're saying there... Even in the realm of gas engines the chevy/ford guys hated racing my mother because my dad always built Mopar engines and they always had torque on everyone. LOTS of trophies on the wall from his last 340 that he built.
 
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torque is neat and all, but timing the throttle input so that the twin turbos will actually be coming up on boost coming off a corner and hoping that 1000ftlbs doesn't kill the tires (or your transmission) doesn't really sound all that fun to me.

550-575hp from a 4BT running down the 1/4 mile or across a mud puddle is one thing. Making it live on a road race course is another.

what kind of induction is allowed on a 4cyl?

why not build a Mercruiser 4cyl and run methanol and a turbo? they use a Ford big block cylinder head and valvetrain.

the thought of a 1,000lb engine (fully dressed with twin turbos, etc.) that's 3ft tall, just doesn't really sound like a road race setup to me
 
Hi Forrest, The car is a speedway car, running 1/4 mile oval dirt tracks just like Sprint Cars run on. With lap times between 12 - 13 secs, it is on boost for only 4 - 5 secs twice a lap which it why it has to build boost quickly, and generate big torque. Being on dirt results in a certain amount of wheel spin, so that helps the drivetrain live. The engine being tall also help the car generate side bit in the turns. The cars run a wing the same as a Sprint Car, so that counteracts the lateral weight transfer in the turns.
 
roger that...

well... it sounds like it might be a worthy eneavour then! :D

be prepared to only get one season out of it... they'll probably put a rule change on you when the season's over :o
 
Forrest Nearing said:
torque is neat and all, but timing the throttle input so that the twin turbos will actually be coming up on boost coming off a corner and hoping that 1000ftlbs doesn't kill the tires (or your transmission) doesn't really sound all that fun to me.

550-575hp from a 4BT running down the 1/4 mile or across a mud puddle is one thing. Making it live on a road race course is another.

what kind of induction is allowed on a 4cyl?

why not build a Mercruiser 4cyl and run methanol and a turbo? they use a Ford big block cylinder head and valvetrain.
the thought of a 1,000lb engine (fully dressed with twin turbos, etc.) that's 3ft tall, just doesn't really sound like a road race setup to me
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we raced with some guys out of Jackson Ohio with one of those setups......its essentially a 429/460 cut in half......very interesting engine.....
 
Forrest Nearing said:
roger that...

well... it sounds like it might be a worthy eneavour then! :D

be prepared to only get one season out of it... they'll probably put a rule change on you when the season's over :o
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x2... After you piss some people off they will more than likely start changing things for you. Also, twins can be fun, but I think that a VGT turbo may suit your needs a little better. That way you can get away with running a single so that would be one less thing they can whine about (they might get cranky about twins).

I will tell you from personal experience, that when they start gearing rules towards kicking you out of a class it's one of the best feelings EVER. Better than winning in my mind :kick: (though I've had my fair share of that too)
 
Yeah, I know what you mean. I got under their skin with the Rotary Mazda powered car. Don't get me wrong, I love V8's. I have a 496 cu in big block (454 bored +60 with 1/4 in stroker crank) in my C20 that used to tow the Sprinter I raced, but I also like being different, and the more I learn about these little Cummins 4B engines, the more I realise just how much potential they have. They are ideally suited to the Modified class, and I just know it will blow away the established V8 top dogs. I am just waiting for approval from the Speedway Board here to allow diesel as a fuel in the class. Once I get approval, then I will start building the engine. Can't wait!!
 
Watch this space. I have bought a brand new ISB4 3.9 Cummins for this project. Looking forward to hearing the first ISB4 hit 7000 RPM. (Well the 6 cylinder ones pull 6700 in the pulling contests
 
More than 5000 with a 4B??? I'd like to see if it is possible to get ussable power/torque beyond 5200rpm.
 
too much smoke out of it and youll be racing by yerself..keep in mind off/on pedal all the time is gonna make the guys behind ya unable to see..good luck with the safety man
 
4B

Great to hear what your going for and I think you will do very well with it.

Being a Mazda Tech can you tell me about your old rotary I just love those little engines!
 
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