Fitted 3.5" Exhaust

[lozza]

Hey guys

I fitted my 4" dump 5" cat and 3.5" exhaust the other week because I dont feel like paying some monkey 500 bucks to do up a couple of bolts and do something I couldnt do in 3 hours in my garage. But I have noticed it cuts out at shorter revs, has less speed at the same revs, (ie I could wind out second to 105 with standard exhaust, now I can only get 95 max). Just did this for an experiement as I know I prob shouldnt be gunning it without a tune. I dont really want to get a tune right now as I'm in the process of getting all my parts together to put on it, and really rather save myself 900 bucks on another tune.

Question is, is it safe to run it without the tune for a couple of more weeks or should I consider one asap?

Is it alrite to give a bootful or should I baby it til its done?

I usually use it for driving to work so it doest usually see the rev limiter, sometimes on the weekend to show up the Expensive Daewoo boys and any other tool that thinks my car is a N/A XR6 (debadged the turbo lol).

Thanks in advance for the help.

[Paulie2256]

Someone will correct me if im wrong but im pretty sure changing the exhaust without a tune may contribute to boost spike. Also because the backpressure has changed it will probably feel a bit slower. I wouldnt risk it and get a tune sooner rather than later.

[lozza]

Cheers mate. Yeh a tune is defianatly on the cards, just trying to put it off til I can get the parts fitted to the car. The exhaust was a nesecity as I kinda squashed my old one lol.

[straughsberry]

If you've relieved back pressure, you should be making a little more power thanks to a little more boost.

[ExAreSix]

What do you mean it 'cuts out at shorter revs'?

I'm assuming you're hitting boost cut. Don't flog it till you get a tune.

An exhaust won't change your gearing. So your 2nd gear redline road speed will not have changed.

[Craig.]

Just to be on the safe side, drive it like your nanna would until you get that tune.

[82CNT]

Your computer will be cutting it out for u thanks to the freeing up of things and as stated the increase in boost. If u have a gauge you would be seeing something far different than the standard 5psi. Be on the safe side and dont hit the loud pedal. It will be fine if u dont give it berries!

[lozza]

Yeh I wish I did have a gauge. One of the things on the to-do list. What I mean exaresix is that it will cut out at say 5 thousand revs instead of the 6000 odd I use to get out of it. Might just be the extra boost revving too hard and surging or anything. I got no idea to be honest. Tune should happen in the next 2-3 weeks hopefully but I was just checking that its not going to do any serious damage in that time

THanks guys

[Dirty32]

You would also want to be very careful bashing 6000 revs...

Definately risking Oil Pump gears (big cost if they go!!) and without a tune, possibly your engine (depending on model of vehicle).

With the exception of drag built monsters, 99% of the cars on this site will not make any more power past 5500 rpm anyways, so you shouldnt need to go to 6000!

[lozza]

  On 11/01/2010 at 1:25 AM, Dirty32 said:

You would also want to be very careful bashing 6000 revs...

Definately risking Oil Pump gears (big cost if they go!!) and without a tune, possibly your engine (depending on model of vehicle).

With the exception of drag built monsters, 99% of the cars on this site will not make any more power past 5500 rpm anyways, so you shouldnt need to go to 6000!

Not too sure if ive pushed it that hard, just a bit of fun down the skidpan was too busy watching the road instead of the rpm, doh!