RichV Posted March 22, 2008 Share Posted March 22, 2008 I blew up the supposedly low mileage motor I bought after about 6 laps last weekend. I have a line on a new built/balanced 306. Stock rebuild/CR/cam/etc. Internals are all stock for a Fox Mustang, pistons are forged, 20 over. I also have a possibility of GT40 heads from a 95 Cobra with 1.7 rockers, and I already purchased a 93 Cobra intake with 65mm T/B. What if I make too much power? I just have a MAC prochamber, a crank underdrive, and an electric fan. My 86 with a similar setup (except BBK headers), but stock E7 heads, made 225/285. Can I restictor plate a Mustang? Dumb question, but is it legal? Quote Link to comment Share on other sites More sharing options...
Glenn Posted March 22, 2008 Share Posted March 22, 2008 i think most all Ford and 3rd gen guys pull timing to get power down. some even play w/ fuel pressure. Quote Link to comment Share on other sites More sharing options...
King Matt1548534716 Posted March 22, 2008 Share Posted March 22, 2008 Per 7.7.2, "cars may install a restrictor plate between the air filter and intake manifold to reduce horsepower and torque," so yes you can. Quote Link to comment Share on other sites More sharing options...
CMC#11 Posted March 22, 2008 Share Posted March 22, 2008 i think most all Ford and 3rd gen guys pull timing to get power down. some even play w/ fuel pressure. Exactly, I pulled my timing back to a "conservative" number and then set fuel pressure and am at 229/278 with a very similar combo to what you described. Quote Link to comment Share on other sites More sharing options...
King Matt1548534716 Posted March 22, 2008 Share Posted March 22, 2008 I'm curious if power adjustments you make solely with fuel pressure are maintained? I've been told by several knowledgable tuners that the EEC-IV will pretty quickly relearn a change in fuel pressure and compensate for it, thus negating the change. I haven't tested this myself since my car has a stock non-adjustable pressure regulator. Quote Link to comment Share on other sites More sharing options...
RichV Posted March 23, 2008 Author Share Posted March 23, 2008 Not for sure on that Matt. But, raising FP will definitely get you more fuel at WOT. Lowering below stock levels can affect injector spray pattern and make the car run rough. At WOT the EEC goes into a open loop mode and will just max out injector pulse and not adjust due to O2 readings. So I think the power can be affected up/down based on pressure. But changing timing and fuel pressure will affect your HP/Tq curves, what is the optimal way to detune?? Quote Link to comment Share on other sites More sharing options...
MHISSTC Posted March 23, 2008 Share Posted March 23, 2008 ...what is the optimal way to detune?? The best way I can think of is if you swap your 306 with the heart of "The Great Pumpkin". If you only need small adjustments you could put the stock sized pulleys back on. After that I'd be inclined to retard the timing. If larger adjustments are needed...can you do a smaller throttle body? After that...restrictor plate. Quote Link to comment Share on other sites More sharing options...
RichV Posted March 23, 2008 Author Share Posted March 23, 2008 ...what is the optimal way to detune?? The best way I can think of is if you swap your 306 with the heart of "The Great Pumpkin". I'll swap you right now! But it's not the 306, it's the 6 lap clicker. Quote Link to comment Share on other sites More sharing options...
MHISSTC Posted March 23, 2008 Share Posted March 23, 2008 Hmmm...I wonder if there is a way we could put that motor in the spare tire well and use it to get our weight where we need it? Quote Link to comment Share on other sites More sharing options...
RichV Posted April 27, 2008 Author Share Posted April 27, 2008 Update. Dynod the new setup. Ended up with stock E7 heads, 1.7s, Cobra intake and TB. Averaged 229.8HP and 274.5Tq on my 3 runs. Can I tune a little better for Tq? I'm running 15deg of timing and a non adj FPR. Thanks!! Quote Link to comment Share on other sites More sharing options...
King Matt1548534716 Posted April 29, 2008 Share Posted April 29, 2008 The Cobra intake is probably hurting your torque numbers. My 5.0L makes 229/294 with E7s and a stock intake, stock 1.6 rockers and an HO cam. Ford revised the Cobra cam specifically to address lost low-end performance from the GT40 intake. Quote Link to comment Share on other sites More sharing options...
Members Al F. Posted April 29, 2008 Members Share Posted April 29, 2008 Plus what exhaust are you running? I've seen these cars react well to a little bit less than wide open system. Quote Link to comment Share on other sites More sharing options...
MHISSTC Posted April 30, 2008 Share Posted April 30, 2008 Since CMC series rules aren't the subject here, I'd love to have a discussion related to what I'm about to suggest in another thread. How about adding a 0.5" or 1" phenolic spacer between the upper and lower intake to ever so slightly lengthen the intake runners and gain a little low end torque? Would either fit under the stock hood? Quote Link to comment Share on other sites More sharing options...
RichV Posted April 30, 2008 Author Share Posted April 30, 2008 Matt, yea I figured as much on the intake. I think at this altitude I'd be hard pressed to make the HP #s with a stocker. When I dyno'd it was with the local Mustang Club and there were several Fox cars on the rollers. 93GT same mods as mine, but a trick flow intake, 210H/256t 89LX same basic mods, 212/261 89GT holley systemax kit, full exhaust 284/309 95GT systemax kit, exhaust, +?? 270/300 Al, I'm running the stock headers with a MAC off road H (the one with the single muffler in the middle) and the exhaust immediately turns and exits out the sides. Scott, I think spacers are OK in CMC, I'd have to check. The other thing would be to offset cam/crank timing, but I don't think that's legal. I think a stock hood can fit 1/2-3/4", but I also have a 3 point strut bar, so it would have to clear that too. http://s17.photobucket.com/albums/b99/myponyrocks/?action=view¤t=MOV00100.flv vid on the rollers. Quote Link to comment Share on other sites More sharing options...
King Matt1548534716 Posted April 30, 2008 Share Posted April 30, 2008 If you are making max. power numbers on a dyno in Colorado, you will probably be quite a bit over the max. at a track like Mid-Ohio. I wouldn't be too concerned about being under power at altitude. Quote Link to comment Share on other sites More sharing options...
nasa-rm Posted April 30, 2008 Share Posted April 30, 2008 If you are making max. power numbers on a dyno in Colorado, you will probably be quite a bit over the max. at a track like Mid-Ohio. I wouldn't be too concerned about being under power at altitude. Except he has to deal with people who are at 230/300 limit at altitude. Quote Link to comment Share on other sites More sharing options...
King Matt1548534716 Posted April 30, 2008 Share Posted April 30, 2008 Boy, I'd be really interested to know how a legal CMC engine can make 230hp at 5000 feet! Quote Link to comment Share on other sites More sharing options...
nasa-rm Posted April 30, 2008 Share Posted April 30, 2008 Simple. Start with an unrestricted bone-stock 260HP engine We just need to bring lot of restrictor plate choices when we come play you guys. Or even with Rich's engine he's got 229.8, just can't find the torque. Quote Link to comment Share on other sites More sharing options...
cmc35 Posted April 30, 2008 Share Posted April 30, 2008 It's going to be interesting to see just how much effect the altitude really has on a dyno run. And no - please - don't turn this into a physics lesson on the subject. I can always go over to corner-carvers and read some rants on the topic. -chris Quote Link to comment Share on other sites More sharing options...
RichV Posted April 30, 2008 Author Share Posted April 30, 2008 If you are making max. power numbers on a dyno in Colorado, you will probably be quite a bit over the max. at a track like Mid-Ohio. I wouldn't be too concerned about being under power at altitude. Yea, I've heard that as well. Quote Link to comment Share on other sites More sharing options...
King Matt1548534716 Posted April 30, 2008 Share Posted April 30, 2008 Simple. Start with an unrestricted bone-stock 260HP engine We're talking about a stock 5.0L here, right? Your definition of "bone-stock" must be a little different than mine. Quote Link to comment Share on other sites More sharing options...
King Matt1548534716 Posted April 30, 2008 Share Posted April 30, 2008 It's going to be interesting to see just how much effect the altitude really has on a dyno run. Ask James Griffith III. Quote Link to comment Share on other sites More sharing options...
Glenn Posted April 30, 2008 Share Posted April 30, 2008 Simple. Start with an unrestricted bone-stock 260HP engine We're talking about a stock 5.0L here, right? Your definition of "bone-stock" must be a little different than mine. Right Matt, he must be running a SCAT crank, H beam rods and an internal balance crank. i bet it dont last him 1 race weekend. Quote Link to comment Share on other sites More sharing options...
MHISSTC Posted April 30, 2008 Share Posted April 30, 2008 Simple. Start with an unrestricted bone-stock 260HP engine We're talking about a stock 5.0L here, right? Your definition of "bone-stock" must be a little different than mine. Right Matt, he must be running a SCAT crank, H beam rods and an internal balance crank. i bet it dont last him 1 race weekend. A '98 4.6L SOHC would have been original to the car...or is this where the update/backdate rule is exercised? Quote Link to comment Share on other sites More sharing options...
RichV Posted April 30, 2008 Author Share Posted April 30, 2008 Boy, I'd be really interested to know how a legal CMC engine can make 230hp at 5000 feet! But, the 230HP is corrected for all of us. The problem is the correction is a calculation. So your 230 at sea level is dead on, where my 230 at real sea level will have error. Uncorrected, I'm sure were at 190ish. Quote Link to comment Share on other sites More sharing options...
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