Scott
Short on Horsepower
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Instructor
Joined: Feb 2005
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From: IL
Short on Horsepower
My '99 C5 w/ 26K miles dyno'd at ONLY 270HP. 
The car has a K&N cold air in take and Borla exhaust too.
What could be the problem, or more important, is there a solution to get back that 80-90HP?????
The car has a K&N cold air in take and Borla exhaust too.What could be the problem, or more important, is there a solution to get back that 80-90HP?????
Le Mans Master
Joined: Aug 2004
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From: NE OH
St. Jude Donor '09-'10
Dyno's differ; Dynojets, for example, read higher than Mustang dynos. Could be any one of a number of things that lead to erroneous #'s. Running it down a 1/4 mile will tell for sure if you are 'really' missing HP.
Safety Car
Joined: Sep 2003
Posts: 3,558
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From: Cape Coral FL
Originally Posted by 1999 Vette
My '99 C5 w/ 26K miles dyno'd at ONLY 270HP. The car has a K&N cold air in take and Borla exhaust too.
What could be the problem, or more important, is there a solution to get back that 80-90HP?????
The car has a K&N cold air in take and Borla exhaust too.What could be the problem, or more important, is there a solution to get back that 80-90HP?????
But I would like to add that on a DynoJet dyno with those mods if you are running an M6 I would expect to see ~310 to 315rwhp and if an A4 ~295 to 300rwhp. If you dynoed on a Mustang dyno those numbers are probably correct.
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Verdad Gallardo
Team Owner
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From: Freestate Corvette Club! Elkridge, MD
St. Jude Donor '17
Originally Posted by 1999 Vette
My '99 C5 w/ 26K miles dyno'd at ONLY 270HP. The car has a K&N cold air in take and Borla exhaust too.
What could be the problem, or more important, is there a solution to get back that 80-90HP?????
The car has a K&N cold air in take and Borla exhaust too.What could be the problem, or more important, is there a solution to get back that 80-90HP?????
The Borla will not add any power - just sound. You MAY get something from the k and n.
We need more information - Is your car an automatic transmission?
What kind of dyno was used (Dyno Jet or Mustang or other)?
Le Mans Master
Joined: Jul 2002
Posts: 7,370
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From: Slave to the evil empire
Cruise-In V Veteran
St. Jude Donor '04
Originally Posted by Ragtop_Rob
You are not missing 80 to 90 hp - The figure GM publishes for hp is at the crank. The roller dyno measures rear wheel horsepower.
The Borla will not add any power - just sound. You MAY get something from the k and n.
We need more information - Is your car an automatic transmission?
What kind of dyno was used (Dyno Jet or Mustang or other)?
The Borla will not add any power - just sound. You MAY get something from the k and n.
We need more information - Is your car an automatic transmission?
What kind of dyno was used (Dyno Jet or Mustang or other)?
To many people see their car has 350 hp and think it will read that on the chassis dyno, this is not the case.
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Instructor
Joined: Feb 2005
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From: IL
This was my first dyno run. It is an automatic too. Honestly, I don't know that much about the mechanics of cars, and I don't know what kind of dyno machine it was (I can find out though). The reason for my concern, is that other vettes have been run on this dyno (same/similar mods) and showed higher HP (340+).
Plus, the tech guy, who has a vette, felt the reading was accurate and that there was an obvious lack of HP output.
Plus, the tech guy, who has a vette, felt the reading was accurate and that there was an obvious lack of HP output.
Melting Slicks
Joined: Aug 2000
Posts: 3,367
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Originally Posted by 1999 Vette
My '99 C5 w/ 26K miles dyno'd at ONLY 270HP. The car has a K&N cold air in take and Borla exhaust too.
What could be the problem, or more important, is there a solution to get back that 80-90HP?????
The car has a K&N cold air in take and Borla exhaust too.What could be the problem, or more important, is there a solution to get back that 80-90HP?????
Sounds like a Mustang dyno. As stated above, the mods you have will most likely show zero gains. Sounds like the dyno op. may be trying to sell you some parts.
Who dynoed the car, location?
Le Mans Master
Joined: Jan 2005
Posts: 5,479
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From: Dallas/Grand Prairie Texas
take it to the track
Definately need to take it to the track, 1/8 or 1/4 to find out.
1/8 should put you around 8.7-8.9 sec. and 1/4 should put you around 13.5 sec. give or take a few tenths.
The dyno's read horse power at the wheels not at the crank, big loss for an Automatic about 18% loss of power , so that 270 RWHP could be accurate.
Also, consider, when's the last time you had an oil changed or trani fluid changed, or other fluids that could possibly effect performance to a slight degree. Just a thought.
I'm about to have my stock 02 automatic dyno'd in a couple weeks, I'm not expecting much more then 285RWHP to be honest, I know I'll be disappointed, but I'll just go out and smoke a Cobra or something to make me feel better... ha
1/8 should put you around 8.7-8.9 sec. and 1/4 should put you around 13.5 sec. give or take a few tenths.
The dyno's read horse power at the wheels not at the crank, big loss for an Automatic about 18% loss of power
, so that 270 RWHP could be accurate. Also, consider, when's the last time you had an oil changed or trani fluid changed, or other fluids that could possibly effect performance to a slight degree. Just a thought.
I'm about to have my stock 02 automatic dyno'd in a couple weeks, I'm not expecting much more then 285RWHP to be honest, I know I'll be disappointed, but I'll just go out and smoke a Cobra or something to make me feel better... ha
Instructor
Joined: Oct 2003
Posts: 216
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From: Southlake TX
A dyno is a diagnostic tool, not a track.
I know many people (F-bodies especially) that have dynoed just over 300 rwhp and still ran 11 second ET's.
There are many different varibles as to why your car dynoed low, perhaps you have some compression issue, leakdown issues, or even tranny issues. Any A4 car wil dyno lower than an M6 and perhaps your tranny was slipping and you didnt even know it.
But as far as your actual numbers, they are not that below par. If I were you, I would do a compression check at least, and go from there.
Take that thing to the track! It might surprise you.
Hope this helps.
I know many people (F-bodies especially) that have dynoed just over 300 rwhp and still ran 11 second ET's.
There are many different varibles as to why your car dynoed low, perhaps you have some compression issue, leakdown issues, or even tranny issues. Any A4 car wil dyno lower than an M6 and perhaps your tranny was slipping and you didnt even know it.
But as far as your actual numbers, they are not that below par. If I were you, I would do a compression check at least, and go from there.
Take that thing to the track! It might surprise you.
Hope this helps.
Thread Starter
Instructor
Joined: Feb 2005
Posts: 185
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From: IL
Thanks all for your help... The reason for my concern, is that I don't want to be blown away by another car and the reason is my car is not performing at the correct HP levels...I want the "bite" that goes with the bark ...anyways, I am going to show these replies to my tech guy and see what he says and keep all of you posted!
...anyways, I am going to show these replies to my tech guy and see what he says and keep all of you posted!
Melting Slicks
Joined: Jan 2003
Posts: 3,251
Likes: 4
Try some new plugs and wires. If you have the stock platinums in there and you've lost the pucks the performance will suffer. I'd recommend the KGN TR55, TR55IX(I found worked nicely to smooth out the idle). The wires get old and the resistance is higher to begin with than many after-market wires like MSD. A loss of 30hp at this level is minimal and probably has more to due with a tune-up than engine issues. If you had something more serious wrong the power loss would be more dramatic. Also, as a side note you will get better hp numbers with a 2.73 rear than with taller gears so crawl under the back end and see what gears you have, it'll say on one of the tags on the rear housing.
Last edited by IM QUIKR; Feb 11, 2005 at 04:27 PM.
Le Mans Master
Joined: Jan 2005
Posts: 5,479
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From: Dallas/Grand Prairie Texas
Originally Posted by IM QUIKR
Also, as a side note you will get better hp numbers with a 2.73 rear than with taller gears so crawl under the back end and see what gears you have, it'll say on one of the tags on the rear housing.
curiuos?
Thread Starter
Instructor
Joined: Feb 2005
Posts: 185
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From: IL
It was tested on a Dyno Dynamics Dynamometer. Does this help you guys with the reading I got (270 HP)?
My concern is that the tech guy felt my numbers were low based on his running of other similar vettes. (I have to ask him what the readings are based on)
Also, what's your advice for next Mods that give noticable results?...(headers/cams)?
Thanks!
PS 90 droptop: I don't want to give out the guy or place as I am confident he is not selling me a bill of goods, he's a good guy with a good rep in the area. Thanks.
My concern is that the tech guy felt my numbers were low based on his running of other similar vettes. (I have to ask him what the readings are based on)
Also, what's your advice for next Mods that give noticable results?...(headers/cams)?
Thanks!
PS 90 droptop: I don't want to give out the guy or place as I am confident he is not selling me a bill of goods, he's a good guy with a good rep in the area. Thanks.
Last edited by 1999 Vette; Feb 19, 2005 at 12:39 AM.
Melting Slicks
Joined: Jun 2001
Posts: 2,743
Likes: 3
From: Davie Florida
Originally Posted by Ragtop_Rob
You are not missing 80 to 90 hp - The figure GM publishes for hp is at the crank. The roller dyno measures rear wheel horsepower.
The Borla will not add any power - just sound. You MAY get something from the k and n.
We need more information - Is your car an automatic transmission?
What kind of dyno was used (Dyno Jet or Mustang or other)?
The Borla will not add any power - just sound. You MAY get something from the k and n.
We need more information - Is your car an automatic transmission?
What kind of dyno was used (Dyno Jet or Mustang or other)?