Just got exhaust, noticed light backfire

[apzak]

I just got a mineake 2.25 inch exhaust with obx b3 muffler. It's extremely loud with my hotshot headers because the pipeing is very straight. All exhaust noise is louder, and because of this, I hear a light back fire/pop after heavy acceleration at times that I couldn't notice because the stock exhuast was too quite. I also hear a light poping if the car coasts at 25mph with 4th gear engaged. My egr is not in all the way, and I don't know if this poping is caused by that. Loose egr's mess up fuel mixtures, but my check engine light hasn't come on. I'm only worried I'm not getting the power I should with the headers. My first modification was hotshot headers, with the stock exhaust. I barely noticed any gains. Once I got the exhaust, I noticed a larger power gain than with the headers. I don't know if the egr is causing loss of power, or the stock exhaust was restricting the headers, and keeping them from producing their power. Has anyone else installed headers before exhaust and noticed the exhaust give more power then the hotshot headers? I had my mechanic look at the egr and asked if he could losen it from the intake side, but it was too tight there and told him if it's a problem don't bother. (I didn't have time)

I'm probably going to get a used gtech on ebay for like $80 just to get a rough estimate on my rwhp. Should be around 145 rwhp with HS headers and exhaust.

[Turbo_Nismo_EC]

Your problem is caused by a lack of backpressure. I have the same problem on my 95 HardBody p/u. MY exhaust is currently 2.5" pipe from just below the manifold to a high flow Catco CAT, and then about 2 v1/2 feet after the CAT I have my OBX B-5 muffler. I asked my engine builder about it and he told me the same thing and said it's not really a backfire but just something having to do with the exhaust system itself. Just like if you ahve a 5-speed and you let the off the gas and around 2500 rpm(atleast in my truck) it starts to make that plop noise. It's the same thing, just at higher RPM. I found that if I let off the gas a little slower when chaging gears under hard acceleration in doesn't pop so much anymore.

[I am Technoman]

I have the same problem too. I also have a code for my IACV but yet it idles perfect. I think it f'ed up the valve doing a induction service.....

[apzak]

technoman - you got email. I can't pm u

[mynismo]

same prob on my exhaust, and most of the people i know have it too. i wouldn't worry about it.

about gtech, tried it and it does a very good job for 0-60 and 1/4 mi, doesnt do hp that well because its a lot different than a dyno. the wind, slant, etc. effect your hp readout.

[apzak]

Will this "popping" damage my valves? It's preaty noticeable when accelerating hard in 2nd to redline, the dropping it in nuetral. I worry my exhaust valves are getting damaged.

[I am Technoman]

Make sure the timing is correct.