Help with results
Thread Starter
Instructor
Joined: Jun 2014
Posts: 185
Likes: 10
From: S W pa. pa
Help with results
I went on a dyno today but wasn,t verry impressed. My hp. was only
207.9 @4190 rpm then took a nosedive. Torque wasn,t bad,296.9@2850
I think I have a breathing problem. 350 / .020 over stock heads (882s)
XE 256 cam / 670 cfm carb. Help me out please.
207.9 @4190 rpm then took a nosedive. Torque wasn,t bad,296.9@2850
I think I have a breathing problem. 350 / .020 over stock heads (882s)
XE 256 cam / 670 cfm carb. Help me out please.
Drifting
Joined: Dec 2004
Posts: 1,714
Likes: 42
From: Austin Texas
I had fun measuring performance gains with a dyno, but the numbers aren't everything.
1. Will the car do a burn out if you had to?
2. Is the car fun to drive?
3. What is your exhaust set up and would you consider a set of headers if you don't have them?
4. Is the car a standard or auto and which transmission? (stock converter?)
5. What is your rear gear ratio?
1. Will the car do a burn out if you had to?
2. Is the car fun to drive?
3. What is your exhaust set up and would you consider a set of headers if you don't have them?
4. Is the car a standard or auto and which transmission? (stock converter?)
5. What is your rear gear ratio?
Thread Starter
Instructor
Joined: Jun 2014
Posts: 185
Likes: 10
From: S W pa. pa
Thread Starter
Instructor
Joined: Jun 2014
Posts: 185
Likes: 10
From: S W pa. pa
I had fun measuring performance gains with a dyno, but the numbers aren't everything.
1. Will the car do a burn out if you had to?
2. Is the car fun to drive?
3. What is your exhaust set up and would you consider a set of headers if you don't have them?
4. Is the car a standard or auto and which transmission? (stock converter?)
5. What is your rear gear ratio?
1. Will the car do a burn out if you had to?
2. Is the car fun to drive?
3. What is your exhaust set up and would you consider a set of headers if you don't have them?
4. Is the car a standard or auto and which transmission? (stock converter?)
5. What is your rear gear ratio?
2 It would be fun even if I had to push it
3 Yes
4 auto (th400) 3:36 in back
Its better at pulling stumps than speeding down the highway
Last edited by hamck; Jun 5, 2014 at 09:54 PM.
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Melting Slicks
Joined: Apr 1999
Posts: 2,010
Likes: 3
From: Moon Twp. PA USA
Stock engine ratings, from the factory, are either 180 or 210bhp. What model engine do you have?
I presently have a '76 L-48 with a stroker. When I had the previous, slightly modified, L-48 dynoed, it returned a 218 RWHP number. This engine was stock bottom end, TF heads, CC 268 cam, true duals, dynomax headers and stock Q-Jet. Have not had the stroker on the dyno yet.
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Thread Starter
Instructor
Joined: Jun 2014
Posts: 185
Likes: 10
From: S W pa. pa
Morning guys
If all I need is some tweeking that would be great. I had visions of $$$$$ on heads and cams etc. Its a L-82 engine. The cams kind of mild (xe256) Thats what comp cams recomended.Ive always read not to over cam. Timings at 36 @2500ish I,ll check for linkage binding mabe the sec. isn,t opening fully. I never had a Qjet, it came with a holley 600. I replaced it with a 670 s/a. Mabe give it more adv??
Glen242 I,m down Uniontown way. Kind of far from you. Theres 2 shops down here that I know of. I got my car from your area in 09.
If all I need is some tweeking that would be great. I had visions of $$$$$ on heads and cams etc. Its a L-82 engine. The cams kind of mild (xe256) Thats what comp cams recomended.Ive always read not to over cam. Timings at 36 @2500ish I,ll check for linkage binding mabe the sec. isn,t opening fully. I never had a Qjet, it came with a holley 600. I replaced it with a 670 s/a. Mabe give it more adv??
Glen242 I,m down Uniontown way. Kind of far from you. Theres 2 shops down here that I know of. I got my car from your area in 09.
Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
While I agree with redvetracr; dynos are a tool to test for better or worse when dialing in an engine, most people do put the car on the dyno to get the "hero" number and neglect to do some testing to see what the engine wants. But running the car on a chassis dyno for tuning is a lot more expensive than just a pull or two for the hero number. Also, if you make no changes and put the car on someone else's chassis dyno, you are very likely to get a different result.
Unless you do find something drastic, like the carburetor primary not going 100 percent, I think you are close...like within 10hp...of everything you are likely to get out of that combination. The cam you're using is actually a bit shorter on duration than the factory L-82 cam. Your performance should be pretty similar to stock.
Finally, the real test is; does the car perform to your satisfaction regardless of what a dyno spit out? While dynos and drag strips are great for data accumulation, you can do a lot of effective tuning outside of those environments.
Unless you do find something drastic, like the carburetor primary not going 100 percent, I think you are close...like within 10hp...of everything you are likely to get out of that combination. The cam you're using is actually a bit shorter on duration than the factory L-82 cam. Your performance should be pretty similar to stock.
Finally, the real test is; does the car perform to your satisfaction regardless of what a dyno spit out? While dynos and drag strips are great for data accumulation, you can do a lot of effective tuning outside of those environments.
Drifting
Joined: Oct 2005
Posts: 1,615
Likes: 150
From: Forth Worth TX
Where did you get the dyno run? I have been looking for a dyno shop near Pittsburgh. Your numbers were from a chassis dyno? If so, your numbers already exceed or equal what the factory ENGINE specs are.
Stock engine ratings, from the factory, are either 180 or 210bhp. What model engine do you have?
I presently have a '76 L-48 with a stroker. When I had the previous, slightly modified, L-48 dynoed, it returned a 218 RWHP number. This engine was stock bottom end, TF heads, CC 268 cam, true duals, dynomax headers and stock Q-Jet. Have not had the stroker on the dyno yet.
Stock engine ratings, from the factory, are either 180 or 210bhp. What model engine do you have?
I presently have a '76 L-48 with a stroker. When I had the previous, slightly modified, L-48 dynoed, it returned a 218 RWHP number. This engine was stock bottom end, TF heads, CC 268 cam, true duals, dynomax headers and stock Q-Jet. Have not had the stroker on the dyno yet.
Drifting
Joined: Oct 2005
Posts: 1,615
Likes: 150
From: Forth Worth TX
Agree with above, check throttle linkage to see if the secondaries are opening all of the way.
Physically look down the carb while someone holds the gas pedal to the floor. (engine off ofcourse)
Physically look down the carb while someone holds the gas pedal to the floor. (engine off ofcourse)
Thread Starter
Instructor
Joined: Jun 2014
Posts: 185
Likes: 10
From: S W pa. pa
Thanks guys Well you take an engine, take it all apart, add new parts, reassemble it and it fires up, your a proud as a new father. Then when your done bragging you go to a dyno, then you realize your not as smart as you think you are. Its a smooth runner, fun to drive, just not the screamer you bragged about. The lesson here is, keep your mouth shut.
Le Mans Master
Joined: Oct 2010
Posts: 6,936
Likes: 848
From: melbourne florida
2023 C3 of the Year Finalist - Modified
Safety Car
Joined: Jan 2009
Posts: 3,736
Likes: 56
From: anchorage ak
Thanks guys Well you take an engine, take it all apart, add new parts, reassemble it and it fires up, your a proud as a new father. Then when your done bragging you go to a dyno, then you realize your not as smart as you think you are. Its a smooth runner, fun to drive, just not the screamer you bragged about. The lesson here is, keep your mouth shut.
Le Mans Master
Joined: Oct 2010
Posts: 6,936
Likes: 848
From: melbourne florida
2023 C3 of the Year Finalist - Modified
Rear wheel dyno results generally are low for an automatic transmission. Run it at the dragstrip and do the math. But I agree some better heads with smaller chambers will help a lot. That's the key to power.