Why do Longtubes make your car run rich?
Thread Starter
On The Tree
Joined: Dec 2001
Posts: 186
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From: San Diego, CA, USA
Why do Longtubes make your car run rich? Topic?
My injectors are maxed 106% at 6100rpm...I wonder if I will be able to scale them down a bit after the LT's are installed.
Thanks Jason
My injectors are maxed 106% at 6100rpm...I wonder if I will be able to scale them down a bit after the LT's are installed.
Thanks Jason
TECH Senior Member
Joined: Nov 2001
Posts: 9,246
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From: Troy, AL
Re: Why do Longtubes make your car run rich? They didn't make mine run rich at all. Sure, the O2s read a little richer at WOT (O2 sensor placement, IMO) but the wideband verified that the mixture was 13.3:1. Hardly what I'd call rich. This was with a stock unported but descreened MAF and stock fuel programming. Also, the Ltrims really didn't change from the stock manifolds and cats to the LTs and no cats. Still right around zero like before.
TECH Senior Member
Joined: Nov 2001
Posts: 9,246
Likes: 3
From: Troy, AL
Re: Why do Longtubes make your car run rich? That sounds good in theory but I certainly didn't see it happen in practice. I really don't think my WOT mixture was effected anything more than slightly by my header install. I believe this to have been the case both times I've added headers to a bolt-on car.
I think the PCM does a fine job of compensating for bolt-ons.
I think all of these folks who think they're running rich after header installs should hook to a wideband before assuming such. They might be surprised.
I think the PCM does a fine job of compensating for bolt-ons.
I think all of these folks who think they're running rich after header installs should hook to a wideband before assuming such. They might be surprised.
Re: Why do Longtubes make your car run rich? I made the remarks from what I've seen <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> 01 cars have a big A/F change with adding headers.My car went from 12.5-1 A/F to 10.8-1 at WOT (3500-6200rpm)on the dyno after adding headers and no tuning.This has happened to 3 cars I know of.A simple change with a MAFT base setting clears most of this up.When the computer adds fuel at idle and cruise(+ L-terms)The WOT throttle is added fuel too.This can be good if your car requires it,but most don't.
TECH Veteran
Joined: Aug 2002
Posts: 4,055
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From: Hartsdale, NY
Re: Why do Longtubes make your car run rich? ...after a cold start with LT headers my car exhaust smells like raw fuel....
...after it warms a bit it seems to be OK
....a friend did an ATAP and told me it was not rich...
I hate headers too...
...after it warms a bit it seems to be OK
....a friend did an ATAP and told me it was not rich...
I hate headers too...
Re: Why do Longtubes make your car run rich? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by robertbartsch:
<strong> ...after a cold start with LT headers my car exhaust smells like raw fuel....
...after it warms a bit it seems to be OK
....a friend did an ATAP and told me it was not rich...
I hate headers too... </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">i agree after the few days after getting headers i reeked(spell check) of fuel, when i got my vehicle dynotuned i found out i was right at 13.0:1 which is in the norm i asked what gives with this stinch, Jayson replied with "all these babies stink with longtubes"
<strong> ...after a cold start with LT headers my car exhaust smells like raw fuel....
...after it warms a bit it seems to be OK
....a friend did an ATAP and told me it was not rich...
I hate headers too... </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">i agree after the few days after getting headers i reeked(spell check) of fuel, when i got my vehicle dynotuned i found out i was right at 13.0:1 which is in the norm i asked what gives with this stinch, Jayson replied with "all these babies stink with longtubes"
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Launching!
Joined: Mar 2002
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From: Houston, Tx
Re: Why do Longtubes make your car run rich? After my LT install A-Tap was telling me I was running rich as well. When I got the car tuned at MTI it turns out I wasn't running rich at all. I think Colonel is right about the sensor placement on the pipes. Yer car is gonna smell if you don't run cat's.
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Verdad Gallardo Thread Starter
On The Tree
Joined: Dec 2001
Posts: 186
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From: San Diego, CA, USA
Re: Why do Longtubes make your car run rich? Thanks for all the replies...I am going to be running cats. I guess I will just need to go to the dyno and use a little LS1edit magic.
Jason <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
Jason <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
Re: Why do Longtubes make your car run rich? <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" /> I was going at the tuning part <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" /> The exhaust WILL smell rich after the header install.LS1 Edit will not help you with the rich smell.
TECH Senior Member
Joined: Nov 2001
Posts: 9,246
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From: Troy, AL
Re: Why do Longtubes make your car run rich? Ok, that's three of us who've widewand tested and saw NO rich condition after headers.
There is an explanation (not necessarily the same one in each case) why occasionally someone really sees a rich condition after headers.
How many times have I seen people go jacking with their MAF sensor outputs based on nothing else than it "smells pig rich now!" Welcome to the world of off-road headers. Get used to it! <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
There is an explanation (not necessarily the same one in each case) why occasionally someone really sees a rich condition after headers.
How many times have I seen people go jacking with their MAF sensor outputs based on nothing else than it "smells pig rich now!" Welcome to the world of off-road headers. Get used to it! <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Launching!
Joined: Mar 2002
Posts: 244
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From: Houston, Tx
Re: Why do Longtubes make your car run rich? if you run cats it will smell like it does now. deleting cats is what makes it smell, or actually cats is what make the exhaust not smell so bad. Hence, its the law to have cats cause yer not polluting as bad. screw the law <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
