XR7 Dave
Registered User
As many of you already know, this year at the SC Shootout Ira Robinson's car made 452rwhp and 479rwtq. This is not the most the car has made though, with 475rwhp being recorded a couple days earlier on a Mustang dyno here in town. This is on a bone stock rotating assemblyeek with about 225,000 miles on the original rings with only a bearing replacement done about 15,000 miles ago. So what makes his car tick? Let's look at it and see.
We already know the pistons, rings, rods and crank are stock. The flywheel and balancer are also stock though a BHJ and/or aluminum flywheel would not hurt the combination any. The motor is in good condition and doesn't really use much if any oil (except for the leaks).
The cam I designed is mild enough to pass emmissions in any state but it does have some lope. Specs are somewhat proprietary but not really super secret. They can be duplicated by any engine builder who knows his stuff.
I ported the heads and they are not welded in any way but there are some significant tricks that are likely only to be discovered with time spent on a flow bench. I wouldn't expect just anyone to be able to get the flow #'s but a good shop should be able to. Exhaust flows over 200cfm but not as much as a Steig head. Valve seats are stock but valves are oversized. Nothing fancy but carefully worked over is the best way to describe them.
The intake manifold is stock other than more careful porting. The inlet is NOT enlarged in any way nor is the return adapter modfied other than for fitting the AR.
The AR is overdriven 17% and makes about 20psi through most of the rpm range. It is complemented with a MPFMIC, MP SC top, MP 85MM TB, and a custom 3.5" intake.
Other bolt ons include UD pulleys, RR's, 80MM MAF, and 60lb injectors.
The exhaust is simple with Kooks mid length headers, 2.5" downtubes, cats (yes you read that right), a 3.5" mid pipe, and 2.5" tail pipes/mufflers.
These numbers were made on pump gas with the help of a dual nozzle alcohol injection system to increase octane and lower air charge temps.
Just thought I'd put that out there.
We already know the pistons, rings, rods and crank are stock. The flywheel and balancer are also stock though a BHJ and/or aluminum flywheel would not hurt the combination any. The motor is in good condition and doesn't really use much if any oil (except for the leaks).
The cam I designed is mild enough to pass emmissions in any state but it does have some lope. Specs are somewhat proprietary but not really super secret. They can be duplicated by any engine builder who knows his stuff.
I ported the heads and they are not welded in any way but there are some significant tricks that are likely only to be discovered with time spent on a flow bench. I wouldn't expect just anyone to be able to get the flow #'s but a good shop should be able to. Exhaust flows over 200cfm but not as much as a Steig head. Valve seats are stock but valves are oversized. Nothing fancy but carefully worked over is the best way to describe them.
The intake manifold is stock other than more careful porting. The inlet is NOT enlarged in any way nor is the return adapter modfied other than for fitting the AR.
The AR is overdriven 17% and makes about 20psi through most of the rpm range. It is complemented with a MPFMIC, MP SC top, MP 85MM TB, and a custom 3.5" intake.
Other bolt ons include UD pulleys, RR's, 80MM MAF, and 60lb injectors.
The exhaust is simple with Kooks mid length headers, 2.5" downtubes, cats (yes you read that right), a 3.5" mid pipe, and 2.5" tail pipes/mufflers.
These numbers were made on pump gas with the help of a dual nozzle alcohol injection system to increase octane and lower air charge temps.
Just thought I'd put that out there.