Strange thing about 55mm piping

AceOdinn

Yesterday installed a new exhaust, no cat at all, middle part was taken from 2.2TD (it's 55 mm), tail pipe - Asso Racing.
And I've got such a wierd feeling that I lost some torque from low rews!
Emmm here's the handmade graph like I feel my engine now.
Did anyone who rebuilded exhaust, notice same thing?

If the acceleration was rather smooth before, now it looks like car just jump forward when it's 3000 revs. Rather uncomfortable, but maybe more fast.

mazza_2_2

From what i have read mate, the Z22se doesn't like no cat at all.
I would put in a 200 cpi sports cat which should give you the power gains your after and provide a smoother power/torque curve.

Matt

on an NA engine, you do need some pack pressure from the exhaust, otherwise you loose torque.

JohnnyN

Last year I removed my centre box and had a straight pipe put in. The car didn't feel the same. It felt quite sluggish with no sense of urgency under acceleration.

1 week later I had a new centre box built and reinstalled. All was well again after that.

AceOdinn

Matt said:
on an NA engine, you do need some pack pressure from the exhaust, otherwise you loose torque.

Well, I've got the same opinion. Just wanted to be sure.
🙂
Thanks, mates!

AceOdinn

Well, I had welded a sport cat instead of just pipe.
And my time per quarter become 17.6 (!)
But without cat it was 15.2-15.4 sec, so tonight will weld and cut again 😃

mazza_2_2

AceOdinn said:
Well, I had welded a sport cat instead of just pipe.
And my time per quarter become 17.6 (!)
But without cat it was 15.2-15.4 sec, so tonight will weld and cut again 😃

So from those results it is obvious that your car is faster without a Cat. But normal driving will feel worse due to the drop in low down torque.
It all just depends on whether you want better quarter times or more comfortable driving.

AceOdinn

mazza 2.2 said:

AceOdinn said:
Well, I had welded a sport cat instead of just pipe.
And my time per quarter become 17.6 (!)
But without cat it was 15.2-15.4 sec, so tonight will weld and cut again 😃

So from those results it is obvious that your car is faster without a Cat. But normal driving will feel worse due to the drop in low down torque.
It all just depends on whether you want better quarter times or more comfortable driving.

Exactly!
I don't want to lose those seconds because with cat car seems to be too slow above 4000 revs!
Even in city it's uncomfortable.
And those drop at low revs are not so terrible.
So I tested my exhaust in all modifications and choosed this version.

Will see time on saturday racing 🙂

PS I'm not using my Astra for drag racing, just riding several times per evening for results.
I use in on racing track, time attacks an so on. 🙂

AceOdinn

So,I had back home at 2AM.
Cat was removed, now a straight resonator took his place (just for some sound deading).
You may take a look:

How it was made, in barbarian style. Or "In Soviet Russia...." 😃 😃

PS Motorola Defy camera suxx 🙁

si_c1978

'in devon' thats how we like to work too!