69ttop502

Just got back from doing 3 pulls at Romar Enterprises in Walden, NY. I highly recommend them. The place was so clean you could eat off the floor. Well back to business. First some information on my motor. It is a 502 GM crate motor with iron rectangular port heads, Flat tappet hydraulic cam with 220 at .050 and lift of .500. It has a #163 Intake manifold with lowered plenum divider and a Holley 750 with mechanical secondaries. The compression ratio is 8.75 to 1. I did 3 pulls, the first was with Hooker reverse flow mufflers in my sidepipes. The second pull was with my baffles from JCL on the forum, and the third pull was with open sidetubes.

1 Max power 246.7 at 4400 rpm Max torque 388.8 at 2200 rpm
2 Max power 338.5 at 4900 rpm Max torque 408.8 at 3900 rpm
3 Max power 342.4 at 4500 rpm Max torque 445.1 at 3800 rpm

These pulls were on a dynojet and measured at the wheels. Can you believe it, I lost 96 horsepower at the wheels with the hooker mufflers. And what the numbers don't tell you is the torque with the hookers from 3500 rpm to 5500 rpm was down almost 130 lb. ft. the whole way. With the baffles I am only down 3.9 horsepower from open pipe. The guys at the shop could not believe their eyes, nor could I. I can't believe Hooker even sells these things and from what I have learned the glasspacks aren't any better. I am now a believer in these baffles. When I figure out how to scan I will post the graphs. I learned my motor definitely needs a cam as it fell on its face right at 5000 rpm. They also told me my fan which doesn't have a clutch could be costing me 20-30 horsepower. In the same room as the dyno they had an alcohol dragster, a nitrous motorcycle and a 9 second camaro. Pretty cool.

gdh

Fantastic, this is the type of post that I truly love to read, thankyou so much!

69 N.O.X. RATT

I would not have thought Hooker would sell something that would cost so much power. I agree, you need a much bigger cam. Hydraulic roller ? :chevy

69ttop502

The other thing I forgot to mention is that although the shop didn't have a decibel meter the baffles are really not that much louder than the hookers but was a totoally different sound. The guy was standing right beside the car while the runs were made and I asked him to judge the sound and that is what he said. Throw away those hooker mufflers everyone.

0Mike69@ECS

Wow! Great #'s!!!!

I gotta order a set of the JCL's. I thought I was getting them for xmas but it never happened. :(

I'm afraid to see what I'm loosing! :cry

MIKER

A 28% hp loss is incredible. You should send Hooker a copy of that dyno sheet. I wonder what their response would be?

Flareside

Wow, great numbers! The real question is "What numbers are you going for NEXT time?" Bill, did they happen to mention if they have a wideband O2 meter?

I think you need a solid roller :D

-Joe

69ttop502

Joe that was another thing I forgot to mention, I dont know what kind of sensor it was but they measured my air fuel ratio on the first run and it was 13.2 to 1. They thought the car was pretty well tuned based on the graphs and I made the runs with 38 total timing all in by 2500. They seemed like a very impressive operation. Check them out Joe. I think they are going to get my headwork. After your post I think I may be leaning to a solid flat tappet although Romar said to not be afraid with a solid roller as long as there is not alot of idling. Well back to square one again on the cam, but at least now I can see how bad I need one.

mountainmotor

Quote:
"I think you need a solid roller "

Think flat tappet solid lifter cam with a Gun Drilled lifter-when you are a long distance from home it will get you back :yesnod:

45ACP

Almost 100 horses lost to muffs?

Something does not sound right . . . :confused:


[Modified by 45ACP, 10:21 PM 2/5/2002]

Chuck Harmon

69ttop502,

Thanks for getting the test and posting it! I knew the Hooker mufflers were bad, but only by seat of the pants.

Are your posted torque numbers correct? I was surprised to see such a low torque number for the JCL spirals, not much more than the Hookers. It would seem that the spirals are very peaky which is not what my experience seemed to be.

Thanks for the story. I need to do the same with mine soon. Sounds like a really great time!

Chuck

marky mark

69 502, Thanks for the great info!

I was wondering about your engine set-up. Is this the GM 502 HO crate motor they advertise? If so, can I assume it does not come with the roller cam like the ZZ502? What type of distributor are you using? And if you don't mind me asking,what do those motors go for? Edit: With the #163 intake- is that a high rise style aluminum factory unit from the 60's? And do you have to go with the L-88 hood to get it to fit?

Regards,marky mark :flag :chevy


[Modified by marky mark, 11:50 PM 2/5/2002]

GDaina

I hope you did not throw those hooker mufflers away....they are mine on loan to Jim.

If you dumped them....you are bad bad boy.

427Hotrod

WOW... Great post!!

Once again proves big motors like to breathe!

My 540 went from 565 to 615 rwhp with the simple change of opening the pipes! Thats 50!!

I have 3" pipes with two chamber Flowmasters.


I bet it's a lot more fun to drive now!! That's like having a new nitrous system and the bottle never goes empty!!


Conngratulations!!


Jim

MikeC

Wow! i thought the mufflers were crappy but not that much.

Dalannex

I agree that you should send a copy of your dyno sheet to Hooker. They may be interested in the results, from the viewpoint of how their product is working in the real world, as well as what the competition has. It wouldn't be a "your product sucks" kind of thing, but just a little friendly note that this is what you came up with at the dyno shop. I would think that their R&D department would be very interested.

SmokedTires

This is a great post as it asnwers some of the questions I had for Jim at JCL. My JCL pipes are ordered, & this post makes me even happier about my purchase :yesnod: :cheers:

Jughead

Great info. Awesome results.

How did it sound with empty tubes?

Len

69ttop502

Len, it did sound great with open tubes but it was LOUD in that big garage. Chuck to answer your question, I am not an expert on this stuff but the torque number for the hookers is very deceiving because it peaked so low and dropped from there whereas the baffles and open pipe had the widest, flattest curve you can imagine. For instance from 3-4000 rpm the baffles made over 400 lb. ft. the whole way, but the hookers went from 360 to 320 lb. ft. over the same period and by 5000 rpm the baffles and open pipe were making the same torque (360 lb. ft.) and the hookers were at 230. The torque curve was a little peakier with the open tube also and it really only outgained the baffles from 2800rpm to 4500rpm. I really should send this to Hooker. When I looked inside that reverse flow I can see why it would lose that much horsepower as I had never seen inside one before. GDaina, don't worry I didn't throw them away.

69ttop502

Marky mark, sorry I didn't answer your question. My motor is the Gen V version of the 502 HO they sell now with the iron heads. The only difference is in the cams. Mine has a flat tappet hydraulic and the Gen VI has a hydraulic roller. Mine is rated at 440hp and the GenVI at 450. I didn't buy mine but I think you can get this motor for about 4500 dollars. I am using a tach drive MSD distributor with a 6AL box. Yes the # 163 intake is the old GM high rise from the sixties. It is the same manifold as the L88 and ZL1 used only you have to mill down the plenum divider yourself. It would not fit under a stock big block hood. I am going with an L88 hood.