521 dyno results

[Tom Wells]

Finally got the thing on a dyno.


pull # 1 : 404 RWHP, 480 Ft-LB.

pull # 2 : 412 RWHP, 460 FT-LB.

These are at the rear wheels, sent through a C6 automatic.



Chart at

CACC web site gallery

Let's go to the Fling!

Tom

[Back in Black]

I cannot wait to get enough miles on mine to dump the demon carb. Sounds like your EFI is working out great, congrats !

[Mohuska]

Tom,

I am also putting the finishing touches on a 521 ci motor. What fuel injection set up are you using? What EFI Controller?...

[Tom Wells]

Hi mohuska,

I'm using the Holley P/N 534-183 "universal" kit with the 1000 cfm throttle body (see your Jegs catalog for details of what it includes). In addition to the kit I had to buy/make/install:

1) Intake area: Torker II manifold, weld on the injector bungs, install the 36 lb injectors, machine the fuel rails and weld their supports to the manifold.

2) Fuel supply: Aeromotive fuel setup, including installing a complete -6AN return line, a -10AN fuel tank bung and pickup, a 100 micron filter, the Aeromotive 1000 pump, a 10 micron filter, a -6AN line from that filter up to the fuel rails and Holley regulator.

Pictures at

CACC link

The Holley Commander 950 computer is still defective in my view and I would not recommend it for street use at this time. It seems to work well at WOT, but is lousy (erratic) at low and part throttle, meaning sometimes it works really really well, but other times the idle goes to 1900 rpm and you have to turn it off and back on to make it settle down again. Right now, it seems to be stuck on "erratic" at low speed! Punch the throttle, though, and the horsepower is definitely there!

Holley is replacing the Commander 950 in June and I hope the new design works better. Apparently the circuit board puts some components too close together and when they are warm, they fight each other! I'll report on the new unit if/when it arrives...

Regards,

Tom

[Naja]

Tom -
Interesting numbers. I haven't done a chassis dyno. I have heard wildly different corrections to account for the drivetrain losses (approx.), but in my slightly larger engine, I got almost 100 more hp and much more than 100 additional fp. Other than the ECU, I have about the same setup.
This raises the question, though, about injector size. Do the people you are working with feel that you are getting the engine's full potential with 36 lb. injectors? (Remember, I am using 65 lb. injectors). What is your Duty Cycle at around 5000 rpm while at maximum acceleration?
Just looked at the dyno curves. I guess that you couldn't log low enough to see the peak in the torque. Also, looking at John's curve (other post), both are somewhat different than mine. I was logged beginning at 2600 rpm. My torque was already at 525 fp, and rose steadily to 548 at 4700 rpm, then tailed off at the typical rate.
BTW, mine is in the shop having the engine rebuilt to the 'specs' that I originally asked for - not a full-out drag racing motor, which is what was built for me, as it turns out. I had 8 valve springs break (one shattered) while driving 35 mph on my Main St. The fellow redoing my engine (and his machinist) said that with the parts I had in the engine, I should never have lasted 1000 miles - I just turned 3100!
I still hope to bring it by your part of the country in late July!?!?
Regards,
Frank Newman

[Tom Wells]

Hi Frank,

Good to hear from you! Sounds like you are going through the "teething" process about like I did

The dyno results shown were limited by the C6, and are taken from the lowest shift point to 3rd onward. Unfortunately the trans won't stay in 3rd below about 3900 rpm at or near WOT, so we were limited to a readout from there upward.

The real test of course is to whack the throttle at 100mph on a dry road and see if the 315/35-17s spin. They do

As to injector size, I have printouts of the fuel pressure and the outputs of the two wideband O2 sensors up to 6000 rpm.

The fuel pressure holds constant at the 44.5 psi setpoint, indicating the fuel supply to the injectors is OK.

The wideband O2 sensors indicate an air/fuel ratio of 13.6 at 4200 rpm, changing to a slightly richer 13.0 at 6000, so my conclusion would be that the 36 lb injectors are at least adequate. Holley claims they'll support up to 575 hp depending on volumetric efficiency.

To answer the duty cycle question directly - no. We weren't recording that, although if I turn on the data log on the laptop next time, I'll try to see what it is. I just forgot to do that this time but when Holley sends the new ECU, I'll take it back to the dyno again, so there is at least another chance for that. It's about 5% at idle

The dyno guy said he uses a 22% loss factor for the C6. I have ~2200 rpm stall I think.

Sorry you are having valve spring problems. That reinforces my switch to a hydraulic roller and appropriate springs to get away from the solid roller which seemed more race-oriented, and kind of high-maintenance for my street purposes.

Let us know when you are in the neighborhood and we'll try to get together!

Tom

[Mohuska]

Frank,

sorry to hear about your motor...I am re doing mine and had two valve springs broken in the heads also...and the cam had 3 lobes that were flattened!!!

My West Coast just finished new paint and interior and we are nearly finished with the new motor

Im installing a 521 with TWM 8 stacker

I have a pic posted in the 429/460 Forum under 460 EFI....anyways...can't wait

Are you going to DVSFIII??

e-mail me...I'd like to catch up on your project...

Mike

Tom...

I agree about the Hydraulic roller cam...I am installing one in my new motor...no more adjusting valve lash and no initial cam break in

Mike

[Tom Wells]

Hi Mike,

Have you decided which hydraulic roller cam you are going with?

When I was looking, Crane had three and Schnieder had some also. I went with the most aggressive Crane: P/N 359351, with their hydraulic rollers.

Maybe there's a bit more to choose from now?

I do like the cam. No-one so far has mistaken it for a small block when it's idling at 750

Tom

[Naja]

Tom & Mike -
The hydraulic roller is what I specified to my builder, originally. An idiot from Comp Cam talked him (and later, me) into using the "racing" parts that were put into it. The guy working on the engine, now, is putting in the hydraulic roller, like I originally wanted.

THANX COMP CAM FOR COSTING ME SEVERAL THOUSAND DOLLARS (extra)! (and the fact that my car has been sitting in the shop during the best driving season of the year - in Houston).

I'm real interested in your TWM setup, Mike. I would like to put one of those in mine in about 2 years.

I am not going to DVSF III.

Regards,
Frank

[Mohuska]

Tom.

I am also using the 359351 cam from crane....we had them grind it so we would get a faster ramp. This will really allow the TWM system to use the extra ramp to develop about 10% more HP and 8-12% more torque.....I am told "It will be a SCREAMER"......

Frank,

Sorry you won't be at DVSFIII...What cam did you finally choose for your rebuild?....believe me..you will really like the TWM set-up....I am also using Electromotive Tec3 controller....no distributor...Direct Fire Coil Units.....

I feel like an expectant father......pace...pace....pace...well you get the idea..

Mike

[Mohuska]

Tom,

How is the idle with that cam...is it lumpy?....or smoothe...?...Do you get good throttle response?

Fill in the details.....

Mike

[Mohuska]

Tom,

How is the idle with that cam...is it lumpy?....or smoothe...?...Do you get good throttle response?

Fill in the details.....

Mike

[Tom Wells]

Hi Mike,

If you look at my gallery you'll see that I have an under the car exhaust. I used 3" tubing and Spin Tech mufflers so it may sound a bit different from yours if you have the external sidepipes and different mufflers.

The sound. How do I go about this? Hmmm....

Well, let's start here: my oldest son and I used to despise stoplights. Because of the idle, we now go looking for them! The car shakes while the engine is idling at 700-750 rpm. Occasionally your vision is blurred by the vibration. In a word, the idle is heavenly . Leaves blow away - far away!

No-one has ever asked if it is a small block

Poke the throttle and everything changes. The sound smooths out to a steady roar. If you have the four wheels all lined up straight ahead you can use more throttle. If not, prepare to spin the 17" tires and possibly the entire car. The sound becomes louder, but the sensation of increasing loudness is much more pronounced than the impression of rpms climbing. Passengers have screamed, and complained that they couldn't read the speedometer because their heads were tilted strongly backward and they were looking at the sky.

I love the sound.

It does get a bit onerous if you go more than two or three hours at a time, or if you have a hangover.

Throttle response is good. It is neck-snapping anywhere over 3000 rpm. When Holley replaces the computer (June?) I'll do some more part-throttle tweaking to improve the 1000-2000 rpm roll-on behavior. Right now there's a slight flat spot in that area.

Can you tell I like it?

Tom

[Mohuska]

It sounds GREAT!!!...That description only make me grind my teeth more

I hope it isn't much longer before I get that neck crackin feeling.......

But until then I'll just keep spinnin

Mike