HSV Extractor - cat modification

[LS1SS]

Good writing on HSV headers and cats,I have a Redline which will only get a tune to which I’m thinking of fitting a set of HSV headers with a 2 1/4 exit and std cats to a 2 1/2 HSV mid with std bi cans to retain std looks,a mate recommends going to Genie 4-2 to 200 cel cats (good/bad?) that bolts onto std pipes or go hole hog and go full Hurricane,I hate decisions.

 

[VF_CalaisV]

Thanks monstar, good to know! So like you have done before the best option when keeping stock cats is to delete the cat to extractor flanges which gives room to help smooth out the cat inlet flow angle. And keeping the velocities relatively high (with approx 2" secondaries) will help the scavenging effect. But for the cat outlet after the gas has been expanded in the cat can it's probably not as important for the high velocities so it should help a little if if take that up to 2.5 or 3" to match the rest of the exhaust.
In preparation for the upgrade do you know what the exhaust shops would have done for the gasket between the cat outlet flange and the catback mid section (as in my attached pic above)? Any compression ring would not have worked because of the size difference. Maybe it's just some flat fibrous gasket??

 

[VF_CalaisV]

@LS1SS If the guy I bought the car from hadn't already fitted the 3" difillipo catback I was going to fit the following: HSV extractors and VE or VF HSV mid section, then your electric bimodal VFII rear mufflers. But I am a bit of a cheap skate and try to spend the least on upgrades that I can.. e.g. buying a 2nd hand VCM OTR for $200 and scrounging the missing brackets from VCM.

 

[Pablito]

Did you get the car tuned when the OTR was put on?
Just asking because you said you were after more power and a tune is where a more noticeable difference will come from instead of exhaust mods.

 

[monstar]

Good writing on HSV headers and cats,I have a Redline which will only get a tune to which I’m thinking of fitting a set of HSV headers with a 2 1/4 exit and std cats to a 2 1/2 HSV mid with std bi cans to retain std looks,a mate recommends going to Genie 4-2 to 200 cel cats (good/bad?) that bolts onto std pipes or go hole hog and go full Hurricane,I hate decisions.

Thing is good value with integrated cats 4-2-1, problem is that does not include a collector / secondary. In other words is constrained to fit at stock catback position and proper secondaries to suit would push the flange back at least 5” to the rear.

Thanks monstar, good to know! So like you have done before the best option when keeping stock cats is to delete the cat to extractor flanges which gives room to help smooth out the cat inlet flow angle. And keeping the velocities relatively high (with approx 2" secondaries) will help the scavenging effect. But for the cat outlet after the gas has been expanded in the cat can it's probably not as important for the high velocities so it should help a little if if take that up to 2.5 or 3" to match the rest of the exhaust.

I think is is important to keep the velocity pumping up all the way out the back, larger cat exit than inlet slows velocity.

In preparation for the upgrade do you know what the exhaust shops would have done for the gasket between the cat outlet flange and the catback mid section (as in my attached pic above)? Any compression ring would not have worked because of the size difference. Maybe it's just some flat fibrous gasket??

No, sorry.

Did you get the car tuned when the OTR was put on?
Just asking because you said you were after more power and a tune is where a more noticeable difference will come from instead of exhaust mods.

Without mechanical improvements to the headers and exhaust you can’t tune this engine to output more than about +10%.
Using HSV headers as part of the tune I was able to raise output +38%.

 

[VF_CalaisV]

Yes, I plan on getting a tune too. Nothing too extreme maybe something similar to the W310 cal.

 

[vr304]

Yes, I plan on getting a tune too. Nothing too extreme maybe something similar to the W310 cal.

If your gonna get a tune may as well go for a full custom tune

 

[LS1SS]

Who has fitted HSV headers and found the damn dip stick tube won’t go along with the easy fit,mongrel thing won’t go in no matter how I try,any one know an easy fix with out using a hammer to get it in? Have been on to Costas re Catco and he’s going to start making 100 or 200 cell cats for these headers.

 

[dimetime]

https://forums.justcommodores.com.au/threads/extracted-performance-vf2headers-and-cats.264534/

old thread, hopefully answers a few questions here

 

[MY17DIR]

Who has fitted HSV headers and found the damn dip stick tube won’t go along with the easy fit,mongrel thing won’t go in no matter how I try,any one know an easy fix with out using a hammer to get it in? Have been on to Costas re Catco and he’s going to start making 100 or 200 cell cats for these headers.

I'd be keen for a nice set of 200 cell cats to use with these headers.