Awesome idea John.
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| Q & A -- Engine Components http://forum.44cup.com/viewtopic.php?f=7&t=225 |
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| Author: | Webmaster [ Fri May 28, 2010 12:23 pm ] |
| Post subject: | Re: Q & A -- Engine Components |
GregF wrote: The disadvantage of allowing the 951 head is that it will put an otherwise stock engine over the HP limit, needing to be "dialed back" via RPM or other means. This will make it a "must have" item, and due the the number of blown up 951 engines out there they are not as cheap or plentiful as the N/A heads. Greg F. If there is a HP limit and people can reach that without it, which many do, why does it become a "must have" item? |
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| Author: | ted63 [ Fri May 28, 2010 2:16 pm ] |
| Post subject: | Re: Q & A -- Engine Components |
Webmaster wrote: If there is a HP limit and people can reach that without it, which many do, why does it become a "must have" item? Conversely, since there is a HP limit what difference does it make how someone gets there? If it is a question of the cost of a 951 head as opposed to other means of reaching the HP limit, why not let people decide for themselves how they want to reach the limit? |
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| Author: | GregF [ Tue Jun 01, 2010 7:02 pm ] |
| Post subject: | Re: Q & A -- Engine Components |
Maybe not a "must have" item then... but I have a whole bunch of legal ITS engines out here that dont quite get to the 144hp limit. The only one that does is a sleeved engine with J&E pistons that makes 144hp on the nose. The rest of us look for 88 engines or at least the piston sets to try and get into the low 140hp range. So if everyone on the East coast is making the limit with no problem using the PCA rules that say it will be standard from the air filter to the exhaust port I guess I have to ask how that is done. Greg F |
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| Author: | JohnB [ Wed Jun 02, 2010 6:11 am ] |
| Post subject: | Re: Q & A -- Engine Components |
GregF wrote: Maybe not a "must have" item then... but I have a whole bunch of legal ITS engines out here that dont quite get to the 144hp limit. The only one that does is a sleeved engine with J&E pistons that makes 144hp on the nose. The rest of us look for 88 engines or at least the piston sets to try and get into the low 140hp range. So if everyone on the East coast is making the limit with no problem using the PCA rules that say it will be standard from the air filter to the exhaust port I guess I have to ask how that is done. Greg F In between other projects been working on a prototype tool to check cams without removing anything (except access through a cam tower bolt access plug). Maybe that will provide some insight? Ya think? |
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| Author: | comatb [ Wed Jun 02, 2010 7:02 am ] |
| Post subject: | Re: Q & A -- Engine Components |
Awesome idea John.
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| Author: | GregF [ Wed Jun 02, 2010 11:36 am ] |
| Post subject: | Re: Q & A -- Engine Components |
That is a great idea. I have always concentrated on reliability in my builds and have not really worked too much in the "grey" areas. Seems like the pre 88 engines come out around 137 to 139hp and the 88 spec engines come out between 139 and 143hp in ITS trim. These were all measured on a Dynojet 248 on the same day. Greg F |
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| Author: | comatb [ Wed Jun 02, 2010 3:56 pm ] |
| Post subject: | Re: Q & A -- Engine Components |
Greg were the pre 88 engines prepared with shaved heads to bring the compression ratio up? |
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| Author: | Director [ Wed Jun 02, 2010 10:28 pm ] |
| Post subject: | Re: Q & A -- Engine Components |
GregF wrote: Maybe not a "must have" item then... but I have a whole bunch of legal ITS engines out here that dont quite get to the 144hp limit. The only one that does is a sleeved engine with J&E pistons that makes 144hp on the nose. The rest of us look for 88 engines or at least the piston sets to try and get into the low 140hp range. So if everyone on the East coast is making the limit with no problem using the PCA rules that say it will be standard from the air filter to the exhaust port I guess I have to ask how that is done. Greg F 144 is the max allowed but its a mistake to think that's the number you should be at. As I have said over and over, a margin for error and fluctuation in dyno results is built into to our max numbers. I tell drivers that if they show with an engine at or near 144, I will dyno them til I catch them over, and then will go over. So the numbers the guys are pulling with a legal build, high 130's, are typical for the power expected out of a well built legal engine. And as John Brown has shown, it takes nothing fancy, or illegal, to get those numbers and win with those numbers. |
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| Author: | GregF [ Wed Jun 02, 2010 10:36 pm ] |
| Post subject: | Re: Q & A -- Engine Components |
Yes, all of the pre 88 engines have the heads cut to near the max SCCA ( shop manual) allowance. The range of power between 6 1984 to 1987 engines is 136hp to 139hp. Greg F |
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| Author: | GregF [ Wed Jun 02, 2010 10:47 pm ] |
| Post subject: | Re: Q & A -- Engine Components |
My engine is from a 1988 924S that had 67,000mi on it when I got it. It has standard crank, rods, pistons, rings, stock valves and valve springs. I use a stock 951 head gasket ( the one that comes in the gasket kits now). The head is match ported to one of our headers exactly 1 inch, the intake ports are untouched. The ECU was done 12 years ago by an employee of Autothority that raced a 944. The exhaust runs at 86 to 89db at 50 ft. pull #1 138.6hp pull #3 141.4hp pull #6 143.1hp 140ftlb best recorded number These are corrected numbers from a Dynojet 248. The operator accidentally dumped the first 3 runs, so we did three more and the number kept going up until it stabilized at 143.1hp. Greg F |
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