Got my engine dyno tuned today

jhaynie · #1 (**permalink**) 09-26-2002, 08:18 PM

Pretty cool process. There's only one guy in Augusta that has one but he only(?) charges $125 per hour. Managed to squeak out 257.4 hp at the rear wheels and 319.2 ft lbs of torque. I guess that pretty good out of a 351W with stock heads, hoped for more though. I can see how this can get addictive, I'm already figuring out how to buy a set of Edelbrock Performer heads and rocker arms the guy had.

Roscoe · #2 (**permalink**) 09-27-2002, 08:18 AM

If you can find my old thread on dyno's there may be some good info for you.

Roscoe

JAM1775 · #3 (**permalink**) 09-27-2002, 12:28 PM

In 1997, my stock FMS 351W crate motor dynoed at 336 rwhp with the same rwtq. This was with stock 9:1 comp, GT40X heads, the crate motor A351 hydraulic flat tappet cam (.520 lift/236/244 duration) 650 BG Race Demon, and a swapped Weaind stealth
dual plane intake. Just some #'s to compare with your set up.

jhaynie · #4 (**permalink**) 09-27-2002, 12:36 PM

My setup is a 1969 Windsor Block, mostly stock cast iron Windsor Heads, Xtreme Comp cam 274 grind, a Edelbrock performer intake and Holley 950 Commander Fuel Injection. Comp is 9.5:1. I am told the greatest HP increase can be realized with the heads and by using roller rocker arms. How true is that?

Brad Pfeifer · #5 (**permalink**) 10-01-2002, 05:40 PM

jhaynie,

Your cylinder heads are strangling your engine! Too much cam and carb for stock heads. Since you have a Performer intake, move up to Performer heads and I think you will see a great increase in power and torque.

Roller rocker arms won't give you much in performance gain, whereas a roller camshaft will.

Change the heads first - it will make a big difference.

Brad

jhaynie · #6 (**permalink**) 10-02-2002, 09:37 AM

Thanks Brad. The guy who tuned the engine had a set of Edelbrock Performer heads slightly used for $600.00. Is tha a pretty good deal. Didn't look like they got used for long. Should you stay away from used engine parts?

Frank Gleason · #7 (**permalink**) 10-02-2002, 12:48 PM

The performer head flows OK for a 302. It's not adequate for a 351. MotionSoftware's Dyno2000 shows 358HP, and 390TQ with the performer head. With a better head, like the ARF 185cc, it predicts 392HP, and 405TQ. Also the curve is much nicer. With the performer head both curves are declining steeply after 4500RPM. With the ARF the curve stays up until 6000RPM.

This is with the 31-246-3 cam, and are not rear wheel numbers.

fg

Mr.Fixit · #8 (**permalink**) 10-02-2002, 12:55 PM

I have used very sucessfully the performer RPM heads on 418 stroked 351w's to make over 500 hp. I like them better (after porting) than the vic jr's which kill low end. Never used the regular performer heads though.

dscott · #9 (**permalink**) 10-02-2002, 03:18 PM

j, I've used the Performer heads many times with good results. With the Performer intake we usually come in around 370hp on the dyno. The performer RPM heads and intake will produce about 415hp on the dyno. The major difference is the valve size, 1.94 vs 2.02. $600 for a good used set seems like a fair price and will help wake the engine up.
Don

jhaynie · #10 (**permalink**) 10-02-2002, 07:11 PM

Don,

This was the engine you built I called you about last week. You'll probably remember our discussion about it having the 950 Commander system instead of the 4DI system you installed.

John

Brad Pfeifer · #11 (**permalink**) 10-02-2002, 08:24 PM

John,

Try this deal - Tell the dyno guy you will give him the $600 cash he wants for the heads if he will give you 1 free dyno run after you get them installed. That way you can see what the difference is, without additional cost to you. It also puts him in the position to stand behind what he is selling you. If he gets kind of squirrelly,maybe the deal isn't what it appears.

Regarding used parts - I think you are OK with heads. Barring something like a cracked head, you can pretty much see anything wrong (bad valve, bad spring, etc). I would be careful about using things like cranks and rods without magnafluxing them.

Frank makes a good point - the AFR heads are showing great results, but they are better than twice as expensive than what you are looking at. And as he notes, Desktop Dyno can 'predict' results but it is not exact.

For the money, go with the Edelbrock heads. Put them on, and if you can get a free dyno test with it - Bonus!! We would really like to know what the new numbers are!

Brad

jhaynie · #12 (**permalink**) 10-03-2002, 07:17 AM

Great idea. Now if you can figure out how to convince my wife that I need to spend another grand on a car I bought a month ago that otherwise runs fine now.

dscott · #13 (**permalink**) 10-03-2002, 08:09 AM

John, That engine does have the stock heads but the valves have been replaced with the 1.94 intake and the 1.6 exhaust. They were also pocket ported and port matched to the intake. I don't recall the dyno numbers but I know it was somewhere around the 325 to 350 range. It sounds like maybe you have a fuel problem with the injection. It should have made better power at the rear wheels. I don't know if you would gain much going to the performer heads. They do flow a little better but the intake and exhaust valves are the same size. If you had room a different intake would improve it. You may also want to try a good carburetor and see if any improvement is gained. I haven't had very good luck with the Holley system on the dyno.
Don

jhaynie · #14 (**permalink**) 10-03-2002, 08:15 AM

Thanks for the info Don. That gives me something to shoot for. I assume the 325-350HP was engine hp. Finding someone who can tune these kits is the trick. I hate to get rid of a $1300 fuel injection system to go back to a plain old carb, but that may be where I'm headed. I could probably sell the FI kit for enough for a new intake and carb.

Mr.Fixit · #15 (**permalink**) 10-03-2002, 08:55 AM

Sell the FI to someone else and let them deal with it. Put a holley carb and a vic jr intake and that should help wake that motor up. If you swap heads, how will your compression change? If it doesn't go up by 1/2 point, you may even lose HP.

dscott · #16 (**permalink**) 10-03-2002, 11:11 AM

John, That was engine hp. The problem I've always had is getting the fuel to flow properly throughout the entire rpm band. Mapping the Holley system was a trick on the dyno but it did perform well. The problem was after installation in the car tuning. Totally different than the dyno. The last time we dynoed the new motor we didn't have the Holley system here so it was on a Holley Carb. If you could find someone in your area that has tuned that system and can create a new fuel map I would give that a try first. All the carbureted engines I build like yours are in that 325 to 350 range depending on the heads. I now use the GTp heads from Ford instead of reworking the windsor heads. We have dynoed some engines with that head at around 365hp. I would think you should have a rear wheel hp of around 280 to 290 with the combo you have.
Don