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!

 

you want as little backpressure as possible , this old street rod myth is wrong.

 

Then why does it run a 15.4 ?

 

is the car running properly?? or is it all just thrown together

 

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

 

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!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Doctor CorteZ &raquo;</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....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DSeriesBKilla &raquo;</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 ?

 

Oil Pressure not Exhaust pressure

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AtomicEG &raquo;</TD></TR><TR><TD CLASS="quote">Oil Pressure not Exhaust pressure</TD></TR></TABLE>

my thoughts as well , heh.

 

The power a bolt-on GSR makes, in a civic, a 15.4 1/4 mile sounds about right.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Marauder &raquo;</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.

 

edit: worded wrong


Modified by Foozball26 at 11:49 PM 8/18/2003

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Foozball26 &raquo;</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 ?

 

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...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Doctor CorteZ &raquo;</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.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93preludeh22 &raquo;</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?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Unsung EM1 &raquo;</TD></TR><TR><TD CLASS="quote">
You want exhaust velocity, not backpressure. </TD></TR></TABLE>

thank you x 10...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93preludeh22 &raquo;</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?

 

They also have a whole lot of output from the motor. The car has a test-pipe also, that might be the problem?

 

regardless of output , constant velocity is what you are after in ANY exhaust application.

test pipe is good , if you can stand the smell...

 

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

 

please reply to the correct person.

IE : the threadstarter in this case...

 

There's no check engine light. The VTEC works.

 

it all shows up in the same thread...or does it?