I installed the Injen dual exhaust today and man does it sound good! It rumbles and vibrates the car somewhat, not too bad, just about right for my tastes (its only the first day tho).....I also have DC headers and Crawford CATS......but i have noticed a loss in low end torque...i went out for 1 drive this evening and will take more tomorrow to confirm, but the car seems to take longer to get up and go.....but pulls good at the top end all the way to redline.....I have seen some of you install an H pipe.....will this help with the torque? Will an X pipe help more? I am planning on a dyno real soon to check the A/F which might be another issue........comments anyone?

shooter

 

many people were complaining that the injen exhaust was spitting out fiber glass.................

 

truplay8.......i talked with a few local guys that had the injen and no problems with the fiberglass issue....i decided to give it a try on that respect...i will for sure be watching for this possible problem.......right now the exhaust is blowing a bunch of white smoke (sort of a light stinky cloud when you pull to a stop) ......supposed to be ok and go away after about 100 miles.....

 

the white smoke is normal and kinda neat... when my injen was installed i gunned it after the engine was warm and it left a HUGE trail of smoke behind me ... looked like my engine was blow

now as far as the fiberglass goes... GL... first you may notice it on your bumper... then you may notice it on your car... next up is INSIDE your car. if this **** is flying around inside its only safe to assume its cutting up your lungs too. i honestly believe EVERY injen exhaust for the G has this problem to varying degrees

ppp

 

pp.....how long did it take for the white smoke to go away for your exhaust? did you notice a drop in low end torque? so you have noticed the fiberglass on your car as well? inside too?

i really like the sound and the slight vibration it gives the car at idle.......nice low throaty rumble, no rasp at all......

 

I have Crawford Heraders and Cats with an Invidia Dual System. I also had a loppey idle. I really didn't notice a loss of low end torque however. But, to cure the idle issue I put in an "H" pipe. It smoothed out the idle, and smoothed out the sound at the tips. IMO, all duals should come with an "H" or an "X" pipe.

Lou

 

thanks lowrider.......i have looked at your pic quite a few times........

the exhaust routes over a cross brace....it is located right behind the resonaters.....in my installation both pipes are touching this cross brace (resting on the brace actually) and causing a metal to metal vibration sound at idle rpms or slightly higher rpms.....I tightened everything up and did not see a way to "adjust" the assembly away from this cros brace.......anyone else have this problem?

i did get to take it out today for some more road time....and wow the G does sound like a BAD A$$ now.......the low rumble and slight vibration can be heard and felt! I dont have any idle problems tho lowrider.......it seems to idle fine, maybe a dip every now and then, but it comes right back up there........

 

[QUOTE=shooter]pp.....how long did it take for the white smoke to go away for your exhaust?

from the time it took me to to go from the install to my house (about 4 miles)
its the oil inside the pipes burning off.

did you notice a drop in low end torque?

no i didnt... however i did run a gtech b4 and after the results showed slower performance after the install... i seriously doubt my car is slower... just way too many variables to consider this info as a fact.

so you have noticed the fiberglass on your car as well? inside too?

unfortunately yes. all over the car and inside i suspect it even scraped the thin azz windshield too

Im sorry i cant offer any solid numbers , but if its any assistance imo the performance decrease was caused by different shifting ( i reset the TCU before the last run)

ppp

p.s. remember the mods you've done are for the mid to upper end of the power band. if I did those i'd expect a loss on the low end.

 

thanks pp.....yep the smoke is gone..........didnt take long, but there is still the smell....like burnt caramel....sort of smells good

the car does pull nicely above 4K ......but i want the low end torque (maybe a 3.9 gear swap?)

i hope to gain the torque back by flashing the ecu for now......hopefully the open throttle, advanced timing and whatever else they do at TS will compensate for the mods......off to the dyno to get that a/f curve!

 

Try this, loosen up your exhaust. Get something around 3/4 inch to use as a spacer. Whatever you decide to use, place it between the cross brace and both pipes so that it is held up off the brace. Now just tighten your exhaust a little bit at a time in each place until tight. Remove the spacers and it should remain above the cross brace. If its not enough space, try it again. I did mine like this and haven't had a problem since.

 

slvrg35........excellent suggestion!

i will do just that this weekend and i know it will solve the problem!

 

i loosened all the exhaust flanges and placed a 3/4 inch spacer (used a hex crow bar) between the pipes and the cross brace......wiggled the pipes to "adjust" them and then tightened everything back up, removed the spacer and viola! the vibration is gone .....the sound is now perfect! no metal to metal vibration.......not too loud and not too soft......deep, throaty note....a great sounding exhaust! but i noticed fiberglass on the rear bumper for the first time today.........i will keep my eye on it and hope it is a short term deal.......luckily the "metal flake" appearance of the fiberglass blends in with my diamond graphite color........

 

Where do you get the H pipe and does it work only for exhaust that is true dual? I have heard good things about this H pipe but is unclear on it's purpose or added performance for the car. Can you please elaborate on this mod?

 

I can tell you that your headers are what most likely caused the low end loss while giving you nice gains on the top end.

This is not uncommon at all with headers.

I plan on doing headers as well and am already prepared for a drop on the low end.

You can try the ECU reflash, but I still wouldn't plan on getting back the low end after it.

Again, this is pretty common after doing headers. Now, depending on the brand you use, you may see some gains on the low end, but for the most part headers will increase HP, but you will sacrifice some low end to get the HP gains.

I just hate to see you wasting time trying to re-adjust your exhaust system over and over. I think you are barking up the wrong tree.

 

"For any performance exhaust system, some type of crossover connecting the two sides of a dual exhaust system is important because it acts to balance the two banks of the engine. The common H-style crossover is good at balancing sound pulses between the two halves, but does little to promote scavenging because the exhaust gases tend to follow the path of least resistance, which is straight through each pipe rather than taking the 90-degree turn through the H-pipe into the other half of the system. In an X-pipe system, however, where the two sides of the system intersect, the gasses have no choice but to intermingle as they pass through the junction. This promotes improved scavenging effects by smoothing out uneven exhaust pulses from the engine’s firing order. It also helps quiet down the exhaust, resulting in a mellower, less raspy tone. According to Magnaflow, the faster acceleration of the gasses through an X-pipe causes them to flow in a linear fashion parallel to the walls of the tubing rather than tumbling. This “laminar” flowing gas is much quieter than tumbling gas, resulting in an exhaust tone up to 8 decibels quieter than a traditional H-pipe."


The above is from an old issue of Car Craft Magazine. Clearly they prefer an "X" Pipe, and from all I have read an "X" is superior to an "H". For my application, I was looking for an easy solution to balancing out both sides, improving the low end, and improving the lopy idle. This was accomplished with my "H". Yes, the "H" will only improve a dual system. I had a muffler shop fabricate it from a piece of stainless, make hole in the sides of my invidia, and weld it in. Pretty easy, actually.

Lou