Hi there folks!

I have a doubt after some modifications i made to my 4.6L 2000 manual Stang.

Not long ago i HAD to replace the Main Intake Mainfold (i think thats the correct name or PIA) beacuse the stock one cracked on one of the corners... after some days of reading about this i found out that its "normal" on my model, that this plastic tends to fatigue, anyway, i replacd it for a PIA (the one with the aluminium bridge).

After that i replaced the air intake for a cold intake bought here, at mustangtuning.com.

Also, on the exhaust system, replaced the 2 back "silencers" with magnaflow (this was the 1st mod i made and man i love the sound)

Then "stupid me" removed the catalytic converters, the check engine light always came up, and the car was buggy as hell, so i bought 2 magnaflow catalytics, the sound went a little low but the "check engine" light has never come on again.

So my doubt here is; Should i re-tune the computer, with a chip so this modifications are used to their full potential? DO I NEED to do it? I undestand with re-tune the computer that it improoves or "fixes" the air-gas mix, is this true?

The car runs great, i DO fell its a little odd in power, i felt it with more power before the intake mainfold replacement.

So what do you guys think? ANY suggestions will be VERY well appriciated!
Hope to hear from you soon,
Regards,
Andrew

 

Put the car on the dyno and get the a/f ratio. Then post the graph here. If anything, you might be running a little lean.

 

Thats a good idea 03GT, Thanx! I know theres a dyno here, i belive its around 40 bucks 3 runs ahah but ill do it this week will post the graph then. Whats the a/f ratio? in case the graph or data comes in spanish...

 

What do you mean whats the a/f ratio? Its the air- gas mix.

 

Disconnect the negative side of the battery and wait for a half hour before reconnecting it to reset your computer, so the cel goes off...

 

ohh good suggestion! ill try that now! thnx!

 

You can take care of pretty much all of those problems (other than the owner... hehehe) with a handheld tuner like the SCT XCal2. You'll need to disable the rear O2 sensors with the tune and probably add a little WOT fuel.

After you get your Dyno run, post the chart up here and we'll take a look. Make sure the air/fuel ratio is logged with the dyno run or it's useless to us.

 

This will most likely fix your problem,or just driving it will too. Just takes awhile.

 

Well 3 months ago i put the cats back in, i was SOOOO tired of the damn check engine light, the damn thing changed the air gas mix or something everytime it went on, the car felt soooo slow...

So i added 2 magnaflow cats and well the sound went a little low, but feels great, havent seen the engine light since then.

Today, i did what you guys suggested, disconnected the neg batt for about an hour, then connected it again and started the car, i left it ilde for 10 mins then went out for a spin, and WOW it fixed it, the stang now feels So much better... the response, i put 1st gear on and BAAAAM it goes off like a rocket!!!

Feels like its fixed now, ill keep an eye on it to see if it stais like that.

Thanx so much for the info, as soon as i can ill take it to the dyno and post the results here... so i can improove the performance with your advices.

Thanx again! ill post it soon!

 

not to hijack your thread draco, but why does your gt have 6 cyl. mustang wheels?..

 

AHAAH this is the 1st time i hear this. I really didnt know those were the 6 cyl wheels :S

Anyway, i want to get the 18" bullit style black deep dish, but the import is going to be expensive!

HEY eres de mexico!!! ahah yo tambien, Guadalajara! tu?

 

haha I was gonna ask the same thing.

 

when changing the way your engine runs, the combination of air and gas flow may be changed, a/f ratio is extremely important because too much of one or another will be bad for the engine.

Quick question, why did you get the manifold changed? It wont help performance unless you have forced induction. And if all you did was get a new catback and/or xpipe, you dont need a tune...a/f isn't affected much at all for that. Usually a tune helps when you get headers, but I've never heard of needing one for exhaust swapout

 

Well i had to change the Mainfold beacuse the stock one cracked on one of the corners. So i bought the PI Mainfold. Then changed the stock air intake system for a cold one. On the exhaust system, it has the stock tubes, just changed the stock catalytic converters to Magnaflow ones, and the silencers on the back for magnaflow aswell.

I was thinking maybe changing to an XPipe, but i have hered it doesnt help much and they are quite expensive here, maybe just a tubes swap, i think the stock ones are 2"? correct me if im wrong. Maybe change them to 2.5"? or 3"? anyone here has done that? I just miss the HUGE "roar" sound it had when i removed the cat's ahha

 

Stock is 2.5" and is good enough. Any bigger and torque will suffer. If you want the roar sound, try different mufflers.

 

oh good to know, besides my Potro is running great, hope to take it to the dyno today!

 

Yeah you don't need 3" exhaust unless you are making well over 500 HP..otherwise your 2.5" will suffice. Si soy de mexcio.....