Dyno'd yesterday and...
Thread Starter
Racer
Joined: Sep 2005
Posts: 330
Likes: 0
From: Lurkerville
Dyno'd yesterday and...
Not impressed. Engine specs - 355 w/edelbrock rpm heads and intake. 750 edelbrock card (electric choke, mech secondaries). Cam duration @.050 234/244, lift at valve .488/.510, 112 lobe sep..
Best pull was 270hp @285 torque. Worst was 245hp @286 torque, lost ignition for a split second and dont know why. A/F was right at 14 to 14.5. I do not like the torque at all and I think I may try to rich'n it up some.
Best pull was 270hp @285 torque. Worst was 245hp @286 torque, lost ignition for a split second and dont know why. A/F was right at 14 to 14.5. I do not like the torque at all and I think I may try to rich'n it up some.
Safety Car
Joined: Oct 2004
Posts: 3,926
Likes: 739
From: Youngstown Ohio
Aim for WOT A/F of 12.5 to 12.8 (this will really wake up the TQ and HP) .....Edelbrocks are easily tunable to keep the cruise A/F ratio higher using the metering rods, and jets for the richer WOT. Mine got better and more controlable results by jetting up the secondaries only.
Last edited by C3 Stroker; Jul 30, 2006 at 04:42 PM.
Drifting
Joined: May 2004
Posts: 1,258
Likes: 0
From: Huntsville Alabama
what rpm was the hp/tq numbers at. Was that flywheel or rear wheel numbers. I don't buy edelbrocks 410/408 they claim on their website with 9.5 compression, even then it should be low 300's to the wheels but it does not feel like it. this cam is in my motor and did not perform under 3500 rpm. I have no low end tq. this cam also does not produce enough vacuum for the brakes either i have a very weak pedal and the brakes are the only thing left on my vette that require vacuum. Good luck with getting where you want it. Im sure others will step in and probaly tell you that the rpm cam is not that great of a design.
Instructor
Joined: Mar 2006
Posts: 107
Likes: 0
hmmm i just got that cam in the mail.....
Damn im a lil upset i just ordered the same exact cam for my 350 boat motor and i was tryin to get into the 400 HP range I have a little bit bigger heads and a weiland intake but yeah looks like i may fall short..... maybe I should send it back???
Thread Starter
Racer
Joined: Sep 2005
Posts: 330
Likes: 0
From: Lurkerville
Originally Posted by 694speed350
Rear wheel or not?
Thread Starter
Racer
Joined: Sep 2005
Posts: 330
Likes: 0
From: Lurkerville
Originally Posted by Silver00V6Camaro
what rpm was the hp/tq numbers at. Was that flywheel or rear wheel numbers. I don't buy edelbrocks 410/408 they claim on their website with 9.5 compression, even then it should be low 300's to the wheels but it does not feel like it. this cam is in my motor and did not perform under 3500 rpm. I have no low end tq. this cam also does not produce enough vacuum for the brakes either i have a very weak pedal and the brakes are the only thing left on my vette that require vacuum. Good luck with getting where you want it. Im sure others will step in and probaly tell you that the rpm cam is not that great of a design.
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Drifting
Joined: May 2004
Posts: 1,258
Likes: 0
From: Huntsville Alabama
Originally Posted by My White 79
I should be running 10.4:1 compression. I had the same vacuum problem, went to the lowest stepup spring in their kit, have 14in now, may go 1 higher to rich'n it up some
Keep us up to date on how everything works out. I am still thinking about keeping the cam because i dont want to deal with swaping out cams. 
Pro
Joined: Jul 2006
Posts: 597
Likes: 0
From: Texarkana Arkansas
Sounds like you've got the complete RPM performer package. Doesnt Edelbrock claim around 400HP from that? Anyway, I used the RPM cam one time and it sucked for me. It was probably my fault though because I built a top end motor, and ended up putting it in a heavy, low geared, 55 chevy truck. Then, I wiped a lobe.
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
What kind of exhaust are you using?
headers?
transmission?
accessories?
All those come into play...
With TH400, all mechanical accessories and a restrictive exhaust, the HP loss can be over 35% from crank to rear wheels...
The carb isn't really a performance carb either. A Holley 4779 would probably give you at least another 10 RWHP...
headers?
transmission?
accessories?
All those come into play...
With TH400, all mechanical accessories and a restrictive exhaust, the HP loss can be over 35% from crank to rear wheels...
The carb isn't really a performance carb either. A Holley 4779 would probably give you at least another 10 RWHP...
Last edited by GrandSportC3; Jul 31, 2006 at 07:17 AM.
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
I pulled 225hp/289tq at the wheels and the car is a screamer with loads of torque arriving around 2000rpm and staying impressive right up to 5000rpm. Much more and I couldn't handle it. Your hp numbers are more impressive than mine but the torque is equal. I'd be happy with those numbers given you are very close to the C5 LS1 performance.
Team Owner
Joined: Apr 1999
Posts: 21,953
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Originally Posted by My White 79
I should be running 10.4:1 compression. I had the same vacuum problem, went to the lowest stepup spring in their kit, have 14in now, may go 1 higher to rich'n it up some
Jets are cheap. all you have to do is change to a bigger diameter jet and the cruise and power A/F ratio will both get richer. The sorry book is just a guidline. Make up your own choices of jet - rod combos.
All it is, is a little math. Just get to an online area of a circle calculator. That way you don't have to to do the pie times radius squared blah blah blah.
Read the numbers on your exsisting rods and jets. The jet is the total flow potential area. The rod diameter area is the minus factor to the jets flow. If you decrease the diameter of the rods - you get more floww and richer jetting. The book only gives you a few big change choices. You can make very fine less than 1% changes to cruise and power fuel ratios.
I have dialed in a few edelbrocks on rear wheel dynos with an exhaust sniffer. we were able to get correct steady state 65 mph cruise and right at 12.8 for WOT clear across the rpm range for max power.
with everything dialed in - like advance curve............... You should be in the 320-330 hp range in the high 5000 rpms