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Hi!
Have the same engine like you in a SPF. Roush rated it at 548 HP (flywheel) with dual plane intake and 870 Avenger. On a Mustang dynameter the result was more or less 450 RW HP. Take a look at my Gallery the sheet is there. It is with stock SPF pipes and headers. Have changed some years later to a Quickfuel cause i had Problems with my Holley. I feel no difference in max. Power, but the Response is faster. Timing and Timing curve is optimized too. This Sumer i will investigate additional time for carb Tuning. If there are missing 50 HP i do not believe that a carb swap will bring the result - if the Avenger is tuned right it will be not a miserable one - and believe me without Tuning a new carb will not work correct. So in any case i would first check the Timing, the Timing curve...then optimize the existing carb and then you will have a solid base. Wish you a great day! Peter |
Exhaust
I had my car on the dyno the other day , Hub dyno 408w and only got 420 at the wheels , with a dip in the torque curve , I thought it might be the mufflers , so we removed the center core (spirals) and picked up 62hp !. Cheers .:)
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Let me add a little Mayhem to the mix. Just got off the chassis dyno my car has a Keith Craft 427 with a motor dyno sheet showing 589hp give or take a few hp. Car went from a Holley 770 street avenger to a Quickfuel750......on the Mustang dyno it made 375rwhp and I will have to get the torque number as I have already forgotten. Pretty disappointing but if it runs better thats all that matters. We even did a compression test as the tuner was a bit alarmed and felt like the car should have been in the 420hp range on his dyno as other 427's have been......and before anyone ask the airfilter was taken off and that only made a 4hp increase. The sidepipes are not stock SPF pipes they are the Firefly brand with 2.5" diameter.
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Like Brent said Mustang dynos show more loss.
Typically another 13% loss compared to the dynojet. It showed that on my dyno session. |
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Clutch slipping? Did you cut the filter open and look for issues with the engine?
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You will probably see black smoke at WOT with 12.5:1.
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Mufflers
I have just recently bought some Flowmaster Slimline mufflers 13530320,like a HP2, these are 4 1/2 OD and have 3 1/2 ID listed and are made of 304 , the internal hole is a lot smaller than expected maybe 2 1/4- 2 1/2 cant measure properly , you have to tig weld your own ends on . Car is still quite loud, actually 1 db less , I tried a different exit pipe that had a 2 1/2 inside the 3 1/2 that exits inwards and down that made the car 5 db quieter , OK on the road but not so good for dusty /shingle drive ways , Haven't gone back to dyno to see if the 408 makes more or less that 554 flywheel HP .The air cleaner I designed and had machined cost me 5KW it is an 11x3 made into an oval , the EFI throttle bodies have bigger linkages to clear ,It is hard to do much else .Cheers
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Knowing your crank hp and rear wheel horsepower shows what is typical for driveline loss.
25-30% would be considered normal. To get your 450 rwhp, you'll need about 600 flywheel. Also shows how many dynos lie. Compression pressure is related to compression ratio AND cam timing. Does your mechanic know what cam you have before stating it should have "xyz" compression pressure? |
My car has 3" I'd sidepipes.....at the track if I remove them and run with open headers there was a gain of about 2 seconds a lap.....on a 1 minute track......
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ACE,
Is your car fast enough? Do you feel you have enough power. If the answer is yes, leave the engine alone and drive. I had a number of stroked 351 to 427's and they all used a quart every 1K to 1.5K miles. Who gives a sheet. Washing cylinder down, yea in 100k miles. Try a different compression gauge and eventually it will read what you want. |
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Be carful with 10 quarts. Every single engine i had the dipstick was wrong by over a quart. the only way to know for sure is drop the pan, fill with water until below windage tray then reinstall and fill with oil and mark dipstick. that being said the oil pump pickup is 1/2" off the bottom of the pan so you have some room to play. If you have a high volume oil pump than you better have enough oil but not to much that it foams. I know you would think it would be simple but it never is.
Lets say you had wash down, which i doubt, it would still take 50K plus miles to know a difference. Sheet two stroke engines use gasoline as a lubricant mixed with 50:1 oil, lol. There is always somebody to take your money. |
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years ago, at one of the cobra builders/ engine shops, I had some work done on my FE 427 (429 displacement), and got 455 rwhp. That same cobra/engine builder had installed numerous roush 427r's, and I think the best rwhp he ever got from any of the crate roush 427r's, was around 420, even after dyno tuning with the best side pipes. So, it depends a lot upon the dyno. |
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As far as the 10 quarts go,that seems like a lot,but you can easily find out,most A/M oil pans (canton for sure) have the parts number on them, easy to see if the car is on a lift, check what type pan it is,take a few measurements if you can't find the part number and look up on their site and you should be able to get the capacity........ I've never seen a Canton SBF pan that held more than 8 quarts,too much oil can be as bad as too little oil...... I have a Canton 8 quart road race pan on my race car and a remote larger than normal filter with 12AN lines,probably a total 8 or more feet of lines and it only holds 10.5 quarts and that's including the oil cooler......my filter alone holds 1.5 quarts........ David |
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