Disappointing Dyno results
Racer
Joined: Nov 2010
Posts: 397
Likes: 33
From: Campton Hills, Illinois
ecs
Glad to hear your happy with the results from our mail order tune!
Thanks!!
Np, BTW Doug owes me a phone call. I know you guys are busy so if you could give me a email addy I'll send my question Thanks again.
Thanks!!
Np, BTW Doug owes me a phone call. I know you guys are busy so if you could give me a email addy I'll send my question Thanks again.
Thread Starter
Racer
Joined: Sep 2000
Posts: 273
Likes: 0
From: Valley City ohio
Don't take this personally because there are a lot of people on forums who post only their max hp values and ask why didn't they gain more??
Here are some things you should consider when looking at the ENTIRE dyno graph.
1) You could have gained 15 hp from 2k-3k rpm but since it's not the maximum HP/TQ you just ignored it.
2) You don't mention TQ how much TQ did you gain?
3) What does your Air/Fuel ratio look like along your dyno graph?
Can you post the before and after graphs???
Here are some things you should consider when looking at the ENTIRE dyno graph.
1) You could have gained 15 hp from 2k-3k rpm but since it's not the maximum HP/TQ you just ignored it.
2) You don't mention TQ how much TQ did you gain?
3) What does your Air/Fuel ratio look like along your dyno graph?
Can you post the before and after graphs???
Safety Car
Joined: Apr 2007
Posts: 3,582
Likes: 136
From: SoCal CA
Does anybody else see that it may be a bit much to ask for 15hp to the wheels by putting headers on a stock LS1? The motor isnt even utilizing the flow capabilities of the headers. On top of that the exhaust is still flowing through the restrictive stock mufflers. So 6rwhp+/- aint that bad for stocker with a cai. Maybe this is one of those situations where someone wants to add the advertised hp by bolting on a part. Remember that highly modded cars pick up 20-30hp avg with headers. Idk, jmo.
Melting Slicks
Joined: Dec 2006
Posts: 2,186
Likes: 2
From: Woodinville WA
Does anybody else see that it may be a bit much to ask for 15hp to the wheels by putting headers on a stock LS1? The motor isnt even utilizing the flow capabilities of the headers. On top of that the exhaust is still flowing through the restrictive stock mufflers. So 6rwhp+/- aint that bad for stocker with a cai. Maybe this is one of those situations where someone wants to add the advertised hp by bolting on a part. Remember that highly modded cars pick up 20-30hp avg with headers. Idk, jmo.
Someone dynos stock at 355whp, puts on headers an air intake and gets a dyno tune and puts down 385whp, and says the headers were worth 30hp. Not true. With just an aftermarket air intake and a tune they usually put down in the low 370whp range, which is really only an increase of 10-15hp for the headers. This is on an ls6 where the flow demands are even higher than an LS1.
Race Director
Joined: Jan 2007
Posts: 18,643
Likes: 14
From: Norman Oklahoma - The Only State in the Union with no Blue Counties!
You are right, the VRB2 numbers will not show up on the dyno! You can get some idication if you place two barrel fans blowing directly into both sides of the grill openings.
Glenn, Bo,,,,crosswinds?
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Safety Car
Joined: Apr 2007
Posts: 3,582
Likes: 136
From: SoCal CA
We are talking a bone stock car. A stock engine just wont create enough exhaust pressure(combustion chamber pressure)to take full advantage of the flow and scavenging effect of headers. The more power an engine makes, the more air it takes in resulting in more exhaust gases to get out. Then it really benefits from headers. The stock exhaust system actually flows pretty decent compared to other cars manifold type setups. They almost look like little shorty headers, not bad for a little 347 making 345-350hp at the flywheel. I would consider headers once someone starts getting into heads/cam or forced induction type of mods. On a stock car it is very hard to justify the price vs gains.
Burning Brakes
Joined: May 2007
Posts: 911
Likes: 27
From: Southern IL
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
331 on a stock motor with headers is about the norm from what I have seen. One other factor to look at, what time of year was the first dyno and this one. Reason for asking is the fuel difference, i.e., winter blend has less BTU per gallon and will read lower on the dyno than the summer blend.
