Sprint car motors?

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doogievlg

doogievlg

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I know a lot of sprint cars run small block mopars but I can't figure out how they are getting 800 or 900 hp out of a small block. I will be the first to admit that I do not know a ton about the small block even after rebuilding a few and being on here for 8 years or whatever it is now. But those numbers just seem insane to me.
 
they are not your stock motor. they are very precise well built blueprinted with custom pistons and rods and crank. ring combo is usually a thin metric combo. cylinder heads are aluminum worked over to provide flow and esp port velocity. the cam usually is a roller, depends on rules. also, they run fuel injection, hilborn style. some run race gas or alcohol.
they turn them lots of RPM. there's more to them. also dry sump oiling. they are not cheap!!! it's an art.
 
Maybe waggin will chime in. He does some sprint car driving.
 
doogievlg said:
I know a lot of sprint cars run small block mopars but I can't figure out how they are getting 800 or 900 hp out of a small block. I will be the first to admit that I do not know a ton about the small block even after rebuilding a few and being on here for 8 years or whatever it is now. But those numbers just seem insane to me.
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It's all about air flow and what it takes to make over 2 HP per cubic inch............
 
Do these motors make monster torque as well? Just curious why you don't see them in any drag cars.
 
doogievlg said:
I know a lot of sprint cars run small block mopars but I can't figure out how they are getting 800 or 900 hp out of a small block. I will be the first to admit that I do not know a ton about the small block even after rebuilding a few and being on here for 8 years or whatever it is now. But those numbers just seem insane to me.
Click to expand...

It isn't too hard to do if the parts are available. Engine design is mostly just math. You pick a CSA to give you the torque peak where you need it and then make sure everything else can support that. If you use a large CSA and move the torque peak up to 8000 rpm then you're going to make a lot of power but you'll need super high quality parts everywhere in the engine to stay together at that speed.
 
doogievlg said:
Csa?
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Cross sectional area, the size of the intake port in the head, bigger the CSA the higher the torque peak.

That's why in engine masters for example you see alot of guys with these huge port heads that have half the port floor filled with epoxy, since I believe the rules require the engine to make power at 6500rpm or less
 
doogievlg said:
I know a lot of sprint cars run small block mopars but I can't figure out how they are getting 800 or 900 hp out of a small block. I will be the first to admit that I do not know a ton about the small block even after rebuilding a few and being on here for 8 years or whatever it is now. But those numbers just seem insane to me.
Click to expand...

Alcohol, DI, good heads, and a light bottom end.
 
twayne24365 said:
Cross sectional area, the size of the intake port in the head, bigger the CSA the higher the torque peak.

That's why in engine masters for example you see alot of guys with these huge port heads that have half the port floor filled with epoxy, since I believe the rules require the engine to make power at 6500rpm or less
Click to expand...

Learned something new there.
 
I haven't followed sprint car racing for a while, but I think the motor costs at that level start at $25K to $40K. They will be sent back to the builder after a certain number of laps for a refresh and get a total rebuild after each season.
 
Me, I'm holdin' out for a Gurney-Weslake............

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79410aspenrt said:
not designed for strip but in a light tube chassis car, 2200-2800 lbs. low 9's to high 8's times slips all day long.
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You could do more for less....a 410 sprint car engine to run with the World of Outlaws is going to run you 50,000....
 
Still remnants of Craftsman truck series engines around too. I stumbled on to this one a couple years back. A dry lake bed racer changed directions. Had two engines, numerous cranks and cams, few sets of heads and two complete engines. The "used" engine he sold for $4500.... and I picked this one up with 7 dyno pulls on it for not much more. Think I saw it's twin for sale on racingjunk awhile back as it did go to Montana.


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The heads flow about 400CFM

The A8 Aluminum block cost is about $9100.00
The Billet crank cost about $5200.00

[ame="https://www.youtube.com/watch?v=2jI6XosZzXg"]Sprintcar 410ci engine on dyno - 887hp@8262rpm - YouTube[/ame]
 
My good friend, retired Chrysler powertrain engineer Greg Charney, built his '68
Dart with a modified version of the MP sprint car engine. He drives it on the street
and it goes very low 10's at the strip. Greg had his car in our tent at the Nat's the
last two years.

The MP sprint car engine does not resemble the civilian A-motor in many respects,
especially the cylinder heads.

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HOT ROD Magazine article:
http://www.hotrod.com/cars/featured/1311-1968-dodge-dart/

[ame="https://www.youtube.com/watch?v=bjyIXDsuvaI"]Greg Charney's 68 Dart with 410 sprint car engine - Milan Dragway ET-10.17 134 MPH 10/9/13 - YouTube[/ame]


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I sure don ' know....
 

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