No Top End...

[Vettefan87]

Why does it feel now that when my car shifts into third at WOT, it is like it just falls on its face? I did not really notice that with the canister mufflers I had on. It is really hard to tell with the noise level and what not. Even my buddy watching me at the track last Friday said "Yeah it just sounded like your car quit when you shifted into third". My brother said his car did the same thing with the muffler eliminators on, but now that he has the dynomax mufflers on his car doesn't. I wanted to borrow his mufflers and run my car at the track, and see if my traps got any higher or not. I would try the elims with chambers in them, but I can't afford it to find out it isn't any better. Anybody have any opinions?

 

[SSTibet]

Hey I am not an engine expert but I have read some amount of exhaust back pressure is needed in the ignition chamber so that the air/fuel mixture does not escape into the exhaust line... Can it be that you have a problem as such because the muffler eliminators may not be providing the back pressure but letting all exhaust flow out freely?

 

[Vettefan87]

That is my thought as well, but I can't afford it to start buying mufflers and putting on the car. It is hard to know what would be the best muffler for my car considering I don't have any cats on it.

 

[Moonunit 451]

Could you be having the same problem Rich mentioned? The car going into OD even though he's only shifted to third. That's what it feels like if you accidentally shift through 3rd to OD on the track, falls down completely.

 

[Mad-Mic]

my car does this sometimes also but it's not going from D to OD.

are you running an aftermarket coil or ignition parts? if so check the cap and rotor. last year i was having ignition problems, alot of burnt wires from the headers but that was obvious. the in obvious part was the cap and rotor burnt up in 3 months. Car runs hard in 1st and 2nd but top of 2nd and going to 3rd falls off and catches again. went with the Accel cap and rotor to match the supercoil and problem fixed.

when you did your headers did you put a heated O2 sensor in? this will make it go super rich and going into third does the same thing i just mentioned but not as noticable. i put my heated O2 in and found about 30 rwhp after the old one fouled out. it doesn't take long for it to foul. put a 5 amp fuse in (as recommended by some forum members on CF) and it popped it. i knew it and had 2 races lined up the next night. sand bagged on a bad tune. next day popped the hood to check the fuse and it was blown. put the stock 30 amp fuse that came with the fuse block and back to blowing the tires off in 1st gear at a 30 roll

if your tune is off what happens is the car is not geared through the rear or tranny to compensate for a lack of power and will bog until it has enough RPM to pull through it. our cars with 2.59 rear gears and a 700R4 tranny isn't the perfect match but it works. the low 1st gear of 3.08 (i think that is what it is in a 700R4 i know it's 3. something) means something has to give in the other gears. 2nd is stretched alittle and third is stretched alot. so this means with every gear shift the car is pulling less and less and when the tune goes out you really notice it in 3rd until the rpm's are above 3500 rpm

It's all about the Tune.....

 

[rrubel]

Could you be having the same problem Rich mentioned? The car going into OD even though he's only shifted to third. That's what it feels like if you accidentally shift through 3rd to OD on the track, falls down completely.

He's got an auto, I think. My issue was the "3" part of the 4+3 kicking in at the wrong time.

Mic, still want to split the cost of one of those MEMCAL emulators? I don't think I can get the used one I was hoping for (guy never emailed me back) but a new one isn't much more.
[RICHR]

 

[Vettefan87]

my car does this sometimes also but it's not going from D to OD.

are you running an aftermarket coil or ignition parts? if so check the cap and rotor. last year i was having ignition problems, alot of burnt wires from the headers but that was obvious. the in obvious part was the cap and rotor burnt up in 3 months. Car runs hard in 1st and 2nd but top of 2nd and going to 3rd falls off and catches again. went with the Accel cap and rotor to match the supercoil and problem fixed.

when you did your headers did you put a heated O2 sensor in? this will make it go super rich and going into third does the same thing i just mentioned but not as noticable. i put my heated O2 in and found about 30 rwhp after the old one fouled out. it doesn't take long for it to foul. put a 5 amp fuse in (as recommended by some forum members on CF) and it popped it. i knew it and had 2 races lined up the next night. sand bagged on a bad tune. next day popped the hood to check the fuse and it was blown. put the stock 30 amp fuse that came with the fuse block and back to blowing the tires off in 1st gear at a 30 roll

if your tune is off what happens is the car is not geared through the rear or tranny to compensate for a lack of power and will bog until it has enough RPM to pull through it. our cars with 2.59 rear gears and a 700R4 tranny isn't the perfect match but it works. the low 1st gear of 3.08 (i think that is what it is in a 700R4 i know it's 3. something) means something has to give in the other gears. 2nd is stretched alittle and third is stretched alot. so this means with every gear shift the car is pulling less and less and when the tune goes out you really notice it in 3rd until the rpm's are above 3500 rpm

It's all about the Tune.....

My Accel supercoil is about a year and a half old, and my cap, rotor, wires, and plugs are a couple of months old, probably 3k miles at best.

Where do I get a heated O2, and wouldn't I throw an O2 code if my car was running super rich due to the headers? Does backpressure really make that much of a difference in the richness, since the O2 is before the cats, and not after it. I am not sure I am following you about the fuse thing...

 

[Vettefan87]

Well I just called AutoZone thinking I could get lucky, and the guy is like "well they don't make anything like that since it gets heated by the exhaust". So am I going to have to go to like a speed shop, or order one online? I am throwing no codes that I am aware of and the car pulls great in first and second gear, it just seems third is flat.

 

[WhalePirot]

Is the CAT clogging? Does the engine easily pull to redline?

 

[MoeJr]

When you run what sounds like basically an open exhaust you tend to lean the fuel mixture with it. It is possible when the car is going into 3rd it is falling flat cause of not enough fuel. I have a gutted cat on my car but with Walker mufflers and I know when I hit 3rd the car pulls very strong but I do have the 3.07 rear. I would suspect u need to put some kind of muffler back on there.

Mic, BTW the first gear in a 700R4 is 3.06.

 

[atmmac]

this doesnt seem to make any sense i know plenty of people with muffler eliminators not having any problems.

 

[Vettefan87]

Okay, I have been reading and for the heated O2's it's Autozone part number #13190, but the guy at one Autozone acted like he never heard of a heated O2, and at the other one said I would have to go to a spedd shop, because that is not a very common part... O2 Pep boys #85392 is what I have heard from other people using them. Will these things fit? I don't want to drop 50 bucks on it if they won't. Also does anybody know, I am asuming these are four wire O2's? Two for the heated part, one for the ECM, and one for the ground.

 

[Vettefan87]

When you run what sounds like basically an open exhaust you tend to lean the fuel mixture with it. It is possible when the car is going into 3rd it is falling flat cause of not enough fuel. I have a gutted cat on my car but with Walker mufflers and I know when I hit 3rd the car pulls very strong but I do have the 3.07 rear. I would suspect u need to put some kind of muffler back on there.

Mic, BTW the first gear in a 700R4 is 3.06.

I have considered this, but I know Mic is running the same setup and he doesn't have mufflers either. The only thing he has on me is chambered elims. If that is what I have to buy then so be it. But at all possible I would like to keep the car the way it sounds. When your mom says she likes the way it sounds, you know that is a good thing.

Is the CAT clogging? Does the engine easily pull to redline?

I don't have any cats on it. My car according to my friend with the VR4 pulls like mad out of the hole and all the way up until redline of second gear. After it shifts to third he said it just is "dead". He even asked me at the track if I shifted it into OD and the motor bogged, on the two runs he seen.

 

[geekinavette]

I come up with a Bosch part number 13913 as a heated O2 sensor...that a few I know have used. The heated sensor will have 3 wires...it gets ground through the threads in the exhaust pipe.

Are you running stock headers or aftermarket? If aftermarket are they ceramic coated inside and out?

rrubel....what MEMCAL emulator are you looking at? I have a "little" experience in this area.

Bill

 

[Vettefan87]

I come up with a Bosch part number 13913 as a heated O2 sensor...that a few I know have used. The heated sensor will have 3 wires...it gets ground through the threads in the exhaust pipe.

Are you running stock headers or aftermarket? If aftermarket are they ceramic coated inside and out?

Bill

I am running TPIS coated LT headers. I do not know if they are coated inside or not.

 

[geekinavette]

The reason I ask.....

Ceramic is a very good thermal insulator. With coating both inside and out you keep more heat inside the tubes...not to mention corrosion protection is needed on the inside also. I run a stock O2 sensor right at the collector and the only time it ever goes open-loop due to "cool" O2 sensor is at idle on a cool day. If yours is only coated on the outside you may need a heated sensor.

I did find out that Hedman coated headers are ONLY coated on the outside.

Bill

 

[Vettefan87]

I don't think they are coated on the inside as well as outside. Does anybody know for sure if they are? I don't want to spend 50 bones if I don't have to, but it would be nice if the car did pull harder up top.

 

[Mad-Mic]

I don't think they are coated on the inside as well as outside. Does anybody know for sure if they are? I don't want to spend 50 bones if I don't have to, but it would be nice if the car did pull harder up top.

it won't hurt. do it and be done with it! wish i would of known this LAST year so i would of got my 12 second time slip

backpressure is a myth by todays terms. only thing back pressure does is counterbalance the airpump (engine) if it's going in fast and coming out slow your making less hp. if it's going in slow and coming out fast your making less hp. perfect back pressure is a true neutral setup where your pulling just as much air as your pushing. back pressure has nothing to do with torque either. thats another myth. if that was the case top fuel dragsters would be running mufflers :L

get the 3 wire AutoZone #13190 $ 43.99. tap into your wiper motor for power with a fusable block in between that and the O2 and run a ground. orange wire towards driver side. pull that plug with key off and use a test light. check it again with key on and you should have power with the key on.

and to answer your question about the O2 throwing a code. NO it wont unless it stops working completely. it will still work even if it's "Fouled". it wiill just be slow and lazy and thats where you get the rich conditions.

 

[rrubel]

rrubel....what MEMCAL emulator are you looking at? I have a "little" experience in this area.

The Ostrich from Moates is my first choice, was also looking at a Romulator. I was offered a used Romulator, but it wasn't much of a discount off the new price so I didn't get it. I'd love to just be able to borrow one for a month or two since I probably wouldn't need it after this - which is why Mic and I are considering splitting the cost of one.

BTW - I too was told that you wouldn't need a heated O2 sensor if your headers were coated on the inside. After Mic's done with my laptop, I'll be able to check whether the car goes in and out of closed-loop like his did before he added a heated sensor.

[RICHR]

 

[geekinavette]

Out of those two I would recommend the Ostrich...if for no other reason than Craig (Moates) is a really good guy. I work with him from time to time.

Have you looked at my little "invention": http://www.speedtronics.net/aboutprominator.asp

Bill