ITR Bottom End, RDR Head, S2S2's, 221whp/151wtq
08-25-2009, 02:16 PM
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ITR Bottom End, RDR Head, S2S2's, 221whp/151wtq
What we have here is the right combination of parts and a solid tune!
B18C
RS Machines US P73 Spec Piston
Stock 87mm Stroke
Ported and Cut Cylinder head by Pat from RDR
Skunk2 Stage 2 cams
Degree'd by Pat from RDR
Performer X Intake manifold
Tri-Y header
E85
Tuned with Crome by Jordan @ MAPerformance.com
B18C
RS Machines US P73 Spec Piston
Stock 87mm Stroke
Ported and Cut Cylinder head by Pat from RDR
Skunk2 Stage 2 cams
Degree'd by Pat from RDR
Performer X Intake manifold
Tri-Y header
E85
Tuned with Crome by Jordan @ MAPerformance.com
Last edited by MAperformance; 08-28-2009 at 07:28 AM.
08-25-2009, 04:51 PM
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Re: ITR Bottom End, RDR Head, S2S2's, 221whp/151wtq
Those numbers seem a little too good to be true. Was that uncorrected or SAE corrected? rarely ever do you see a 81x87 make that kind of trq.
08-25-2009, 05:05 PM
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Re: ITR Bottom End, RDR Head, S2S2's, 221whp/151wtq
Why not? My 81.5x87 made 142 lbs on a stock port GSR head and OEM ITR header. But it does seem kinda high for those cams though.
Any track times?
Any track times?
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08-26-2009, 02:33 AM
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08-26-2009, 03:33 AM
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Re: ITR Bottom End, RDR Head, S2S2's, 221whp/151wtq
Impressive numbers. At first I was a bit skeptical about those totals. ITR’s can get up to and around 140tq on 93 octane, rare.
Since the head was PnP’d maybe the chambers are smaller and the head has been milled, I bet this engine is at least around 11:1 to 11.5:1.
But they did use E85, ~116 octane.
SAE would be nice, but since this post is from a shop I would expect it to be SAE.
Tuning on Crome with that flat of an A/F? Surprised. Maybe if the resolution was a bit smaller instead of 0-25, how about 10-15.
Since the head was PnP’d maybe the chambers are smaller and the head has been milled, I bet this engine is at least around 11:1 to 11.5:1.
But they did use E85, ~116 octane.
SAE would be nice, but since this post is from a shop I would expect it to be SAE.
Tuning on Crome with that flat of an A/F? Surprised. Maybe if the resolution was a bit smaller instead of 0-25, how about 10-15.
08-26-2009, 05:45 AM
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Re: ITR Bottom End, RDR Head, S2S2's, 221whp/151wtq
In for 1/4 time and trap speed as well.. is this stock bore? These sleeves must be at the service limit.
08-26-2009, 06:39 AM
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Re: ITR Bottom End, RDR Head, S2S2's, 221whp/151wtq
I didn't build this engine. JDM P73 pistons. The head was cut and reshaped. It has small chambers for sure. I'd venture to say atleast 12:1 compression based on the ignition it wanted.
No track times yet. His closest track is 3hrs away. He runs it on the street alot though.
No track times yet. His closest track is 3hrs away. He runs it on the street alot though.
08-26-2009, 06:58 AM
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Re: ITR Bottom End, RDR Head, S2S2's, 221whp/151wtq
i built the engine two years ago and can verify the dimensions. i cant remember for sure if they are RS machine replica ITR pistons or if they were p73's. also the head flows around 285cfm at .500" at 28". i cut the head a lot and the engine has around 13:1. the cams are degree'd in also. just goes to show what can happen when you build a good combo and have good tuning. this engine isnt just thrown together stuff. a lot of time went into gettting all the clearances right. good quench, small chambers, good airflow.
08-26-2009, 07:50 AM
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Re: ITR Bottom End, RDR Head, S2S2's, 221whp/151wtq
From the man himself! Great work on the head as always Pat!
However i don't think it has that much compression...
08-26-2009, 08:52 AM
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Re: ITR Bottom End, RDR Head, S2S2's, 221whp/151wtq
i cant remember off hand but i think the head is cut like .060 or .070
just punching in some stuff on zeals calculator with 82mm USDM pistons that would put it at 13.1:1 cut .060, 13.9:1 if they are jdm P73's cut .060
idk how close that site's calculator is. i always cc everything and figure it out that way but i'm sure i dont have the sheet on that engine anymore.
just punching in some stuff on zeals calculator with 82mm USDM pistons that would put it at 13.1:1 cut .060, 13.9:1 if they are jdm P73's cut .060
idk how close that site's calculator is. i always cc everything and figure it out that way but i'm sure i dont have the sheet on that engine anymore.
Last edited by lohatch; 08-26-2009 at 08:58 AM.
