EXHAUST PRESSURE? Do I have enough?
08-18-2003, 05:53 AM
#1
Honda-Tech Member
Thread Starter
Join Date: Aug 2003
Location: Baltimore, MD
Posts: 1,067
Likes: 0
Received 0 Likes
on
0 Posts
EXHAUST PRESSURE? Do I have enough?
I looked at a 92 civic EG with a GSR motor swap in it. It had MSD ignition, port/polish, top end built up, dc type R header, no cat, skunk2 cat-back, skunk2 intake manifold. The car was sweet. I was just wondering why when I drove it, the power band kind of died off at around 5krpm to 8krpm.. It just didn't pull as hard as the rest. I think maybe the exhaust might not have enough back pressure causing it not to get any power. If you have any ideas, give me a hand. The car is sweet though. I might buy it. Thanks for any help!
08-18-2003, 07:31 AM
#5
Honda-Tech Member
Join Date: Nov 2001
Location: CALIFORNIA
Posts: 15,366
Likes: 0
Received 0 Likes
on
0 Posts
Re: EXHAUST PRESSURE? Do I have enough? (93preludeh22)
is your vtec working? are you using the right ECU? do you know what cams are in there? I am running a 2.5" exhaust system and the car runs better from 5k-8k...
I just noticed you said the top end was built.. . could be built shitty or you could of gotten ripped off... also check your compression.
Modified by b(series)cruz at 8:52 AM 8/18/2003
I just noticed you said the top end was built.. . could be built shitty or you could of gotten ripped off... also check your compression.
Modified by b(series)cruz at 8:52 AM 8/18/2003
08-18-2003, 07:49 AM
#6
Honda-Tech Member
Thread Starter
Join Date: Aug 2003
Location: Baltimore, MD
Posts: 1,067
Likes: 0
Received 0 Likes
on
0 Posts
Re: EXHAUST PRESSURE? Do I have enough? (b(series)cruz)
It's not -my- car yet. I believe the problem lies in the exhaust. He had all the work done at a shop in philadelphia called "IMPO"... So, i think it's really good work. He told me I'd see a big difference when the silencer goes in the muffler. Because there's no backpressure at all, no cat, no muffler (straight-throught..) Help me!
08-18-2003, 07:51 AM
#7
Honda-Tech Member
Re: EXHAUST PRESSURE? Do I have enough? (Doctor CorteZ)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Doctor CorteZ »</TD></TR><TR><TD CLASS="quote">you want as little backpressure as possible , this old street rod myth is wrong.
</TD></TR></TABLE>
last time I checked VTEC needs backpressure....I may be wrong but I don't think I am....
</TD></TR></TABLE>
last time I checked VTEC needs backpressure....I may be wrong but I don't think I am....
Trending Topics
08-18-2003, 08:25 AM
#8
Honda-Tech Member
Join Date: Nov 2001
Location: ...
Posts: 6,400
Likes: 0
Received 0 Likes
on
0 Posts
Re: EXHAUST PRESSURE? Do I have enough? (DSeriesBKilla)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DSeriesBKilla »</TD></TR><TR><TD CLASS="quote">
last time I checked VTEC needs backpressure....I may be wrong but I don't think I am....</TD></TR></TABLE>
and why would it need that ?
last time I checked VTEC needs backpressure....I may be wrong but I don't think I am....</TD></TR></TABLE>
and why would it need that ?
08-18-2003, 09:28 AM
#10
Honda-Tech Member
Join Date: Nov 2001
Location: ...
Posts: 6,400
Likes: 0
Received 0 Likes
on
0 Posts
Re: EXHAUST PRESSURE? Do I have enough? (AtomicEG)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AtomicEG »</TD></TR><TR><TD CLASS="quote">Oil Pressure not Exhaust pressure</TD></TR></TABLE>
my thoughts as well , heh.
my thoughts as well , heh.
08-18-2003, 09:41 AM
#12
Honda-Tech Member
Join Date: Jun 2002
Location: MA
Posts: 3,569
Likes: 0
Received 0 Likes
on
0 Posts
Re: EXHAUST PRESSURE? Do I have enough? (Marauder)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Marauder »</TD></TR><TR><TD CLASS="quote">The power a bolt-on GSR makes, in a civic, a 15.4 1/4 mile sounds about right. </TD></TR></TABLE>
er....ok. with a really horrible driver.
if you are thinking exhaust, it's not a lack of back-pressure that would cause this problem, rather excessive back-pressure. similar to a clogged cat or some such thing. of course, if it's straight pipe with no cat, that would be pretty difficult to do. an even more likely problem would be a lack of vtec engagement.
er....ok. with a really horrible driver.
if you are thinking exhaust, it's not a lack of back-pressure that would cause this problem, rather excessive back-pressure. similar to a clogged cat or some such thing. of course, if it's straight pipe with no cat, that would be pretty difficult to do. an even more likely problem would be a lack of vtec engagement.
08-18-2003, 10:09 AM
#14
Honda-Tech Member
Join Date: Nov 2001
Location: ...
Posts: 6,400
Likes: 0
Received 0 Likes
on
0 Posts
Re: EXHAUST PRESSURE? Do I have enough? (Foozball26)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Foozball26 »</TD></TR><TR><TD CLASS="quote">when you lose backpressure you lose torque, but GAIN hp</TD></TR></TABLE>
um , yeah ok.
where do you get this incorrect data from ?
um , yeah ok.
where do you get this incorrect data from ?
08-18-2003, 01:56 PM
#15
Honda-Tech Member
Thread Starter
Join Date: Aug 2003
Location: Baltimore, MD
Posts: 1,067
Likes: 0
Received 0 Likes
on
0 Posts
Okay, the civic pulls a lot harder with a silencer... I think the exhaust is TOO open.. I've been told by a lot of people that the exhaust pressure really does matter. The car has no back pressure at all really...
08-18-2003, 08:48 PM
#16
Honda-Tech Member
Join Date: Jul 2002
Location: Dallas, Tx, USA
Posts: 1,860
Likes: 0
Received 0 Likes
on
0 Posts
Re: EXHAUST PRESSURE? Do I have enough? (Doctor CorteZ)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Doctor CorteZ »</TD></TR><TR><TD CLASS="quote">
um , yeah ok.
where do you get this incorrect data from ?</TD></TR></TABLE>
ok I worded that statement wrong and left out some key words, you'll move the powerband up and lose some low end but gain it in the upper rpms.
um , yeah ok.
where do you get this incorrect data from ?</TD></TR></TABLE>
ok I worded that statement wrong and left out some key words, you'll move the powerband up and lose some low end but gain it in the upper rpms.
08-18-2003, 09:58 PM
#17
Junior Member
Join Date: May 2002
Location: Italy
Posts: 170
Likes: 0
Received 0 Likes
on
0 Posts
Re: (93preludeh22)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93preludeh22 »</TD></TR><TR><TD CLASS="quote">Okay, the civic pulls a lot harder with a silencer... I think the exhaust is TOO open.. I've been told by a lot of people that the exhaust pressure really does matter. The car has no back pressure at all really...</TD></TR></TABLE>
The problem lies elsewhere. You want exhaust velocity, not backpressure. With the setup listed, it sounds like the exhaust isn't the problem. Is there a test pipe in place or what the exhaust extended to the header?
The problem lies elsewhere. You want exhaust velocity, not backpressure. With the setup listed, it sounds like the exhaust isn't the problem. Is there a test pipe in place or what the exhaust extended to the header?
08-19-2003, 05:13 AM
#18
Honda-Tech Member
Join Date: Nov 2001
Location: ...
Posts: 6,400
Likes: 0
Received 0 Likes
on
0 Posts
Re: (Unsung EM1)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Unsung EM1 »</TD></TR><TR><TD CLASS="quote">
You want exhaust velocity, not backpressure. </TD></TR></TABLE>
thank you x 10...
You want exhaust velocity, not backpressure. </TD></TR></TABLE>
thank you x 10...
08-19-2003, 05:15 AM
#19
Honda-Tech Member
Join Date: Nov 2001
Location: ...
Posts: 6,400
Likes: 0
Received 0 Likes
on
0 Posts
Re: (93preludeh22)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93preludeh22 »</TD></TR><TR><TD CLASS="quote">I've been told by a lot of people that the exhaust pressure really does matter. The car has no back pressure at all really...</TD></TR></TABLE>
dont you think if more backpressure made power that people that build racecars would run something other than open header?
dont you think if more backpressure made power that people that build racecars would run something other than open header?
08-19-2003, 07:47 AM
#22
Honda-Tech Member
Re: (Doctor CorteZ)
If there is a problem exhaust is not it. You are talking a 1-5hp/lb.-ft difference that your butt can't feel. In all probability there is something wrong with either the fuel delivery or vtec. Does it throw a code? Is the correct ECU in there, I think the GSR ecu is a p72, someone confirm that. With the GSR you also have the added complexity of the secondaries, are those working? I would take it to an independent shop for a check-up before I buy. Just my .02