PRC 225 cam and PRC stage 2.5 5.3 heads
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PRC 225 cam and PRC stage 2.5 5.3 heads
Since the cats out of the bag on these great new heads, I'll follow up with my results from them along with PRC's new 225 cam. All my mods are in the sig except for the electric WP, these runs were with full accessory belt (exept the small AC belt, I don't have AC on the car anymore), thru a 22 inch bullet muffler dumped at the rear end. The first graph was with the 10 bolt and motive 4.10's in it, the second graph is with the new moser 12 bolt, 33 spline eaton HD posi and a stock steel driveshaft. I have a chromoly one ordered from AP engineering to replace the steel one with. The cam specs are 225/225 112 lsa 110 icl .589/.589. I was guessing I'd lose around 7 to 10rwhp with the 12 bolt swap. I want to thank Terry at Racetech Speed for giving me a great rate on some dyno time to gather data with. As soon as the chromoly DS gets here I'll have some track results.
Last edited by gomer; 08-26-2004 at 02:15 PM.
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Originally Posted by BoneSS
That is around what you made w/ some of the LS6 style heads isn't it? Awesome numbers by the way.
Both the dyno runs I posted with the 225 cam are with the belt on.
Last edited by gomer; 08-26-2004 at 02:16 PM.
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Originally Posted by JDPZ28
nice numbers!
got any flow #'s for the heads?
got any flow #'s for the heads?
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The 474 HP was belt-off, 10 bolt, 230 cam, different heads.
The 451 HP was belt-off (no A/C or WaterPump), 10 bolt, 225 cam, PRC heads.
So you are down 23 HP. The absolute #'s are very good for a 225 cam, but I'm trying to understand where the 23 HP was lost. Some is due to cam swap. What was the difference in compression ratio? If you dynoed at Terry's new shop, there could be a few HP in dyno differences.
Maybe your original heads were a great set.
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Originally Posted by Ragtop 99
The 474 HP was belt-off, 10 bolt, 230 cam, different heads.
The 451 HP was belt-off (no A/C or WaterPump), 10 bolt, 225 cam, PRC heads.
So you are down 23 HP. The absolute #'s are very good for a 225 cam, but I'm trying to understand where the 23 HP was lost. Some is due to cam swap. What was the difference in compression ratio? If you dynoed at Terry's new shop, there could be a few HP in dyno differences.
Maybe your original heads were a great set.
EDIT: Ok, I just found my graph of the LS6 heads, F13 cam, with ALL BELTS and it was 456/415.. so dyno'd the same way I lost 5rwhp and gained 6rwtq with a smaller cam and less compression.
Edit again, I'm attaching the F13 LS6 heads belt on dynorun vs the 225cam 5.3 heads belt on dynorun.. apples to apples, only thing different is heads and cam.
Last edited by gomer; 08-26-2004 at 02:50 PM.
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A 230 cam versus the TSP 225 cam is not worth 20 HP. Look at the ramps on the 225 cam. 10 HP is more realistic.
A 1/2 point in compression is not worth 20 HP, maybe 10 hp.
However, removing the A/C belt and adding the EWP are worth something too so they need to be added back.
I'm not saying the PRC heads are bad; the absolute numbers with that cam are excellent, it's that he started from a very high baseline. I gotta say you must have pretty big gonads to want to mess with a set-up that put down 456 RWHP.
A 1/2 point in compression is not worth 20 HP, maybe 10 hp.
However, removing the A/C belt and adding the EWP are worth something too so they need to be added back.
I'm not saying the PRC heads are bad; the absolute numbers with that cam are excellent, it's that he started from a very high baseline. I gotta say you must have pretty big gonads to want to mess with a set-up that put down 456 RWHP.
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the more I look at this post the more impressed I am. Figure you add back that 1/2 a point in compression, would put you about 460rwhp, a cutout @465-470rwhp, 90mm LSX w/90mm T/B @480rwhp? With a 225 cam
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My Drive Shaft from AP engineering came in today (thanks guys!!) so I'm going to install it tomorrow, dyno again and go to a local 1/8th mile track on the ET streets and skinny's and see what I can do... I'll post up results tomorrow night (if it doesn't rain)
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Originally Posted by BoneSS
Cutout, TSP MS3, and Fast Intake/TB = 500? W/ Gomers' car, I wouldn't doubt it.
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Originally Posted by gomer
My Drive Shaft from AP engineering came in today (thanks guys!!) so I'm going to install it tomorrow, dyno again and go to a local 1/8th mile track on the ET streets and skinny's and see what I can do... I'll post up results tomorrow night (if it doesn't rain)
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Originally Posted by CamaroCain
OMG, you are actually going to the track and plan to compete at the Thunder Shootout?? It will be nice to see some track times from your car instead of just high dyno numbers
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Dunno what everyone's fuss is over.... but if you look at the comparing graph, he's up all across the power band. His peak isn't quite as much but, its minimal. Great setup gomer
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Scott's car is extremely strong. I went up to get a clutch installed and he let me drive it. The car pulls like a raped ape I've never felt anything like it- especially with slicks. The whiplash is insane. His car felt a lot stronger than just 451rwhp. I couldn't imagine what these heads would be like with the MS3 in it. Maybe this time he can actually get past 60 ft . And if anyone is worried about streetability it was great. A friend of mines ws6 with the 231/237 actually felt worse. As soon as i switch to the MS3 I'm definitely going with these. Maybe I'll even beat Scott because of course 98's are the fastest