i have a 95 200sx that i use for dirt track racing...the car is very fast besides towards the end of the races it seems to be losing alot of power. i only have a header and flex pipe on it with no 02 senors. im sure no 02 sensors may be the problem...also on restarts for cautions a newer pontiac sunfire pulls from me hard almost like these motors have no bottom end at all......the motor isnt getting warm,..sounds more like the clutch is slippen when it gets warm. coming out of the corners she is lugging bad while everyone else still has the pulling power. any suggestions would be nice,..thank u

lol, no o2 sensors is gonna be a problem, yes.

I bet your MAF is dirty as crap too.

These cars do not have a really powerful bottom end, the peak curve is fairly flat. Keep in mind that peak torque comes in at about 4800rpm. And with little backpressure from removing the catback, your low end power is going to suck.

how new of a pontiac sunfire? if it's a 2.2 pushrod, non-ecotec, having a ton of bottom end torque is pretty normal. But even the ecotecs are tuned for amazing low end power. I've driven both. They're just designed that way. Our cars were not.

it was the sunfire with ecotech motor i *** that much,...im gonna try and put the first 02 sensor in and see how it does....these motors deff have the top end compared to most the cars out there...just need to figure out why its loosen so much power....ill check the MAF and c how it looks...thanks buddy

http://www.motoiq.com/MagazineArticles/tabid/59/articleType/ArticleView/articleId/12/The-Great-Wideband-Shootout-Part-1-How-do-wideband-air-fuel-sensors-work.aspx

read this, o2 sensor on 95's are narrow band, only made to monitor stochiometric, any time you floor the car it completly ignores the o2 sensor, narrow band o2's are meant for idle and cruising

I think you would smell your clutch if it was slipping that much. Do you have a temp gauge that reads degrees or just the dummy gauge? You might wanna cut some holes in the hood and give it as much air flow as possible. I'm assuming you don't care much about it if your dirt track racing.... Since it runs ok at the beginnning, something HAS to be getting warmer than it wants to and causing your loss of power.

I've seen ecotecs do pretty gnarly burnouts and was blown away by one. My favorite 4 cylinder motor in the world. Too bad it's not a reliable motor, otherwise i'd be driving an '05 Cavalier right now.

As far as wideband sensors go, they are useful only if you are tuning your car. Particularly when you run turbo. They would not help here because you don't have a tune to take advantage of them, plus you're not heavily modded either.

So, basically when you floor your car, it monitors the fuel ratio less with ours. Eh, big deal. You get worse gas mileage and emissions than a wideband would. But that's not what you're going for, so.

A temp gauge would be a good place to look. I use a scangauge II for that, but there are plenty other tools. Yeah, you could be overheating a little. Or you could have heavy heat soak. A scangauge II can monitor your intake temperatures too. And a lot of other stuff. There is also a cheap consult port cable + software combo going for under $100 these days.

My BMW was famous for lying about it's temperature, from within +/- 30 degrees. Our temp gauges on the dash are not exactly accurate either.

But your lack of low end torque compared to the ecotec is part motor design, part extreme loss of backpressure by going straight pipe!

the link I posted looks like it's about wideband o2 comparison, but it really explains how o2 sensors work and explains why our o2 sensors don't do anything at wot

ok one more thing,...the first race out i broke the passenger side cv joint caz the boot ripped along time ago and i never noticed,,..but i bought a new axel, after the first race on it, it had a small hole in it so i pumped some grease in and ran another race,,,well it ended up rippen the boot right off so there must be a problem somewhere caz it did it to the last boot when it was a daily driver,..any idea what could be causing this?