Dissapointing Dyno run
Thread Starter
Drifting
Joined: Mar 2001
Posts: 1,600
Likes: 0
From: Valencia (near LA) CA
Re: Dissapointing Dyno run (MNJack)
According to the Dynomax website the Flowmasters are killing me!
IT sys that HP x 2.2 = CFM needed
490 HP x 2.2 = 1078 CFM needed
For Dual exhaust I would need a Muffler capible of 539 CFM each, the Flowmasters are only 362 cfm.
Maybe I can redeem a significant amount of HP!! Headers plus Better mufflers :)
~Jay
IT sys that HP x 2.2 = CFM needed
490 HP x 2.2 = 1078 CFM needed
For Dual exhaust I would need a Muffler capible of 539 CFM each, the Flowmasters are only 362 cfm.
Maybe I can redeem a significant amount of HP!! Headers plus Better mufflers :)
~Jay
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Re: Dissapointing Dyno run (Jay M)
Jay- The Ultra Flos should be quieter than the Flowmaster 50s and PERFORM the way you need them to! I think they are an awesome sounding muffler as well.
-Steve
-Steve
Le Mans Master
Joined: Nov 2000
Posts: 8,220
Likes: 208
Re: Dissapointing Dyno run (Jay M)
Here's one alternative if you are looking to replace the stock iron manifolds:
http://www.sandersonheaders.com/page...num/qp2000.htm
http://www.sandersonheaders.com/page...num/qp2000.htm
Thread Starter
Drifting
Joined: Mar 2001
Posts: 1,600
Likes: 0
From: Valencia (near LA) CA
Re: Dissapointing Dyno run (groovyjay)
Those are very interesting! But are they worth the expense and do they work as well as normal headers?
I saw something else on the Sanders websight that was very interesting. They have a chart showing recommended pipe size per HP and ci displacement. http://www.sandersonheaders.com/completeperftech2.htm
According to that I need 3" exhaust.
Do you think this is true? The expense and noise of 3" exhaust might be a problem. But I didn't pay $7000 for a 300hp engine! Will a 3" exhaust fit through the cross member?
Thanks,
~Jay
~Jay
Race Director
Joined: Jan 2000
Posts: 13,015
Likes: 2,259
From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
2020 Corvette of the Year (performance mods)
C2 of Year Winner (performance mods) 2019
2017 C2 of Year Finalist
Re: Dissapointing Dyno run (Jay M)
3" will fit through crossmember if you have a good muffler guy. Mine is fine and doesn't rattle at all.
The 2.5" is far from optimum, but it isn't killing you too bad. I was running lo-11's@123 mph in my '67 capped up through 2.5" pipes all the way out the back. Uncapping it made little difference at the track. This was with a 6500+ rpm 427 making 423 RWHP.
The Dynomax's are good mufflers. I didn't have much resonance issue with the 40 series, but as airflow requirements got heavy, they couldn't handle it. The ultrflows are great too.
JIM
The 2.5" is far from optimum, but it isn't killing you too bad. I was running lo-11's@123 mph in my '67 capped up through 2.5" pipes all the way out the back. Uncapping it made little difference at the track. This was with a 6500+ rpm 427 making 423 RWHP.
The Dynomax's are good mufflers. I didn't have much resonance issue with the 40 series, but as airflow requirements got heavy, they couldn't handle it. The ultrflows are great too.
JIM
Thread Starter
Drifting
Joined: Mar 2001
Posts: 1,600
Likes: 0
From: Valencia (near LA) CA
Re: Dissapointing Dyno run (427Hotrod)
Ok,
as usual you guys have helped me tremendously and cost me a small fortune!!
My current plan-
add Headers
replace 2.5" exhaust with 3" exhaust
Replace Flowmasters with Something better- probably Dynomax
Then take the car to a shop an hour away that does carb tuning on a chassis dyno to fine tune it.
I own the headers already, but they may need to be modified
Mandrel bent 3" exhaust including header installation and mufflers I'm guessing $1200
Dyno tune maybe $300?
So $1500 for hopefully 80 rwhp isn't a bad deal.
~Jay
as usual you guys have helped me tremendously and cost me a small fortune!!
My current plan-
add Headers
replace 2.5" exhaust with 3" exhaust
Replace Flowmasters with Something better- probably Dynomax
Then take the car to a shop an hour away that does carb tuning on a chassis dyno to fine tune it.
I own the headers already, but they may need to be modified
Mandrel bent 3" exhaust including header installation and mufflers I'm guessing $1200
Dyno tune maybe $300?
So $1500 for hopefully 80 rwhp isn't a bad deal.
~Jay
Thread Starter
Drifting
Joined: Mar 2001
Posts: 1,600
Likes: 0
From: Valencia (near LA) CA
Re: Dissapointing Dyno run (Jay M)
I got a quote from the muffler shop. He says it will be under $1000 to install the headers, 3" exhaust with H pipe, and Borla Mufflers. Other mufflers would be slightly cheaper.
I'm keeping my fingers crossed that he won't have any problems with the headers.
Hopfully he can get to it this week :) If so, I'll post new dyno results this weekend.
~Jay
I'm keeping my fingers crossed that he won't have any problems with the headers.
Hopfully he can get to it this week :) If so, I'll post new dyno results this weekend.
~Jay
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Thread Starter
Drifting
Joined: Mar 2001
Posts: 1,600
Likes: 0
From: Valencia (near LA) CA
Re: Dissapointing Dyno run (Pacin'California)
That's a damn good price for all that PLUS Borla mufflers. I do not think you will be disappointed! Should feel almost like a cam swap.
-Steve
-Steve
~Jay
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Re: Dissapointing Dyno run (Jay M)
If your running a hydraulic cam, you got about as much as your going to get. If you want power over 6000 RPMs and to pull to 7000+ it will require a solid lifter camshaft and a good set of valve springs. Also, a 3/8`s fuel line is quite adequate to handle the engine. Thats all that is necessary for the L88`s and ZL1`s, including the 454 LS7`s that produce an honest 550+ HP tuned correctly.
