Ls1 Exhaust Systems

[AngryRB]

Thanks cuspub and Thunder for those posts, its not too late yet but was planning the extractors and cats to be done next week.

These posts really open up a can of worms, Ive actually been reading a lot of your posts Thunder on the ls1 site, I think you said on there that when tuned there wasn't much difference between tri -y and 4 into 1 down low but I didn't think the ground clearance would be an issue on stock suspension, I will keep it stock for ride comfort.

I don't think mine will stay too standard in the long run, my current plan is to do full exhaust, mafless tune, and im thinking a manual conversion ( as funds become available) as ive seen plenty of 6speed box's with most accessories for around $1500, so selling my auto would make it appealing cost wise...

As with the R33, most people want response and low end torque, but when giving some stick its more rewarding if it pulls hard to the redline or close, eg ( gt3076 on rb25) , so for the sake of future mods I'm still leaning toward the 4 into 1's, I know I seem to have changed my thinking from the first posts, just seems ill get bored eventually by having a good bottom end but then giving it squirts and feeling its legless....

What I don't want is a situation where it is very doughy down low and thirsty, with stock exhaust I managed a 11L/100km mixed driving, was babying it a bit with some odd squirts.

This Youtube video sounds ideal to me and is what made me get the DF catback, it sounds quality without being silly loud. https://youtu.be/A_xcV4nMvdQ

Also the 4 into 1's on these youtube clips do seems to sound deeper than tri-y?? this one also is what im after sound wise , https://youtu.be/SJ9Zblxhwuw

I think that single system probably is better, would be much simpler , I think the twin system quietens it down too much, I think for now im going to get the extractors and cats and see how it sounds, might get the 3.5 single later and sell the DF if it doesn't sound good enough.. can do that anytime really.

Wish I lived in NSW, would of been easier to come visit Thunder from the start , so will the 4 into 1's make it less torquey than standard?? I don't wanna go backwards too much...

Edited March 19, 2015 by AngryRB

[cuspub]

Hey Count. I am not an exhaust expert like thunder for example. In fact Greg has an awesome reputation for his product. All I can say about the older HSV systems is that whether HSV or SS, they both love a more free flowing system. In fact it's fair to suggest that the LS1 (vt to vz) responds far better than their later brethren.

[AngryRB]

How many cats does the 3.5inch system use?

so what is your recommendation Greg, for an angry sounding exhaust system similar to the youtube vids I showed, just want to make sure that if I got the 4 into 1's that I can still use them with the cats if I change to the 3.5inch catback.. assume that it will go manual and probably a mild cam , around 250-300kw.

This Youtube sounds meaty, https://youtu.be/CYHOVS4lc44 and yes of course that thing is gonna get thrashed lol.. that guy is funny!

Edited March 19, 2015 by AngryRB

[Thunder]

The only model HSV headers that were good from the factory are the VY2, and these are nearly as good as a set of aftermarket tri-y's. They are still a bit restricted in the collector, but far better than any other model. VT-VY1 are rubbish so don't bother with them.

From the extractors you have one cat on each side. The 3.5" system is twin 2.5" which merges into a single 3.5" system, so it still uses both cats.

The video clips you posted that sound good have cams fitted, which makes them sound aggro, and they sound even better with a 3.5" system. The size of the cam and the way it is tuned also have an effect on the sound. Search on Youtube for "Sureflo 3.5" and you will probably find some cammed cars up there as well. Ballistic 100cpsi Racing cats also make the sound a lot louder and deeper and add around 10rwkw to your power.

The price of 2nd hand cars now, if you want to modify a car, I would seriously think of selling yours and upgrading to a VZ - VE which have the 6.0 litre, that way you can look for a manual. On the VE they spread the wheels by 100mm so it also handles better. It may not cost much in the changeover, so I would look around.

The 5.7 is very doggy down low, but the 6.0 has far more power and torque right through the rev range. The modifications you are talking about are probably $10k and will have it going as good or a bit better than a stock 6.0 litre. I would start with the 6.0 litre and then bang for buck you will get much more enjoyment.

On a 5.7 if you want to fit 4>1 you really need to upgrade the diff to 3.73 for auto or 3.9 for manual which will fix the lack of power and torque down low. This is probably another $1500 on top of the manual conversion. The cam/valve spring upgrade will probably cost $5k by the time it is tuned, and then you may need to upgrade the fuel as well. You are talking big money if you are going this far, but if you traded for a manual VZ or manual VE the changeover won't be too much if you look around.

They were also selling the VF GTS supercharged crate engines for around $13k-15k brand new - that would be a weapon straight out of the box!!!

It's only money!!!

Cheers

Greg

[butterfly effect]

The system appears to have a natural resonant point that is inconvenient. It is all a black art. Repositioning any component in the exhaust will have an effect. This sometimes can't be done. I presume it has a balance tube or x pipe. If not fit a balance tube. If it has either of them temporarily block one pipe at the exit and go for a short drive and see if the drone is gone. Big chance it has. Bigger mufflers will probably have a positive effect. Active systems rid this problem. Anyway do the block test . (Active Exhaust Systems)

[Count Grantleyish]

The only model HSV headers that were good from the factory are the VY2, and these are nearly as good as a set of aftermarket tri-y's. They are still a bit restricted in the collector, but far better than any other model. VT-VY1 are rubbish so don't bother with them.

The price of 2nd hand cars now, if you want to modify a car, I would seriously think of selling yours and upgrading to a VZ - VE which have the 6.0 litre, that way you can look for a manual. On the VE they spread the wheels by 100mm so it also handles better. It may not cost much in the changeover, so I would look around.

The 5.7 is very doggy down low, but the 6.0 has far more power and torque right through the rev range. The modifications you are talking about are probably $10k and will have it going as good or a bit better than a stock 6.0 litre. I would start with the 6.0 litre and then bang for buck you will get much more enjoyment.

Thanks Greg and I'm beginning to think I'd better off moving on with my VX2 into something modern like VE, simply cos they respond to mods better plus newer chassis.

Oh and another question for you, how restrictive are VE HSV headers? Every time I tried to ger answer, people dribble stuff like brand x is the best followed by another person saying brand y is the best blah blah.

I know I can search/ask these holden/hsv forums but I can't spend more than 30 seconds before punching the laptop cos I can't comprehend what they are saying haha.

[Thunder]

The dual 2.5" systems sound disappointing, so DF removed their "Kiss Pipe" (merge) and it basically just has a small hole between the pipes. This makes the sound beefier and why they do it that way. Other people chop out mufflers to make them sound better and this increases the drone.

Yes, fitting a proper full flow merge will help with the drone. Yes, fitting bigger mufflers will make it drone less, but it also kills the sound. Bi Modal systems, ie vacuum operated valves, block the flow in order to stop the droning. They work, but they also restrict the power. These are all costly.

There is no substitute for R&D as there is a balance between power, sound & no drone, and most systems fail on one or more of these.

It is no use having a no drone system that sounds like a vacuum cleaner, or one that blocks a pipe to stop the drone as it robs power.

It is no benefit spending 3 times the amount you need to spend using a system with valves when it robs power and sound as well.

With lots of experimenting and R&D you can have a 3.5" system that is completely straight through, sounds great and doesn't drone.

The difference being, it was specifically designed for this car, for auto and manual, and so it makes power, sounds great and doesn't drone.

Cheers

Greg

Cheers

Greg

[gtr jet]

Cheers

Greg

[Thunder]

Thanks Greg and I'm beginning to think I'd better off moving on with my VX2 into something modern like VE, simply cos they respond to mods better plus newer chassis.

Oh and another question for you, how restrictive are VE HSV headers? Every time I tried to ger answer, people dribble stuff like brand x is the best followed by another person saying brand y is the best blah blah.

I know I can search/ask these holden/hsv forums but I can't spend more than 30 seconds before punching the laptop cos I can't comprehend what they are saying haha.

On the VE, the pipe into the cat is only 2" or 2.25" at best and it comes from a vertical angle into a chamber. This creates turbulence and a big restriction as the gas has to change direction to horizontal to pass through the tiny 600cpsi holes in the cat and exit through a 2" hole. Therefore whether it is the HSV headers or the Holden Manifolds, it still has the same restriction.

We do a set of 4>1 1-7/8" stainless extractors that are tight to the engine and finish in 3.5" with an internal spike in the collector. Our Ballistic 100cpsi Racing cat is a 5" body which is 3.5" inlet and after the gas passes through the substrate it tapers down to 3" pipe size. We offset the body of the cat upwards, so it doesn't hang low, even on lowered cars. No O2 harness extensions are needed and the cat back sports system shouldn't need to be modified.

Cheers

Greg

[zebra]

Kinda off topic...But, Greg do you guys do any decent headers for a 5L (304) Vt commodore?

[Thunder]

Thanks Greg and I'm beginning to think I'd better off moving on with my VX2 into something modern like VE, simply cos they respond to mods better plus newer chassis.

Oh and another question for you, how restrictive are VE HSV headers? Every time I tried to ger answer, people dribble stuff like brand x is the best followed by another person saying brand y is the best blah blah.

I know I can search/ask these holden/hsv forums but I can't spend more than 30 seconds before punching the laptop cos I can't comprehend what they are saying haha.

On the VE, the pipe into the cat is only 2" or 2.25" at best and it comes from a vertical angle into a chamber. This creates turbulence and a big restriction as the gas has to change direction to horizontal to pass through the tiny 600cpsi holes in the cat and exit through a 2" hole. Therefore whether it is the HSV headers or the Holden Manifolds, it still has the same restriction.

We do a set of 4>1 1-7/8" stainless extractors that are tight to the engine and finish in 3.5" with an internal spike in the collector. Our Ballistic 100cpsi Racing cat is a 5" body which is 3.5" inlet and after the gas passes through the substrate it tapers down to 3" pipe size. We offset the body of the cat upwards, so it doesn't hang low, even on lowered cars. No O2 harness extensions are needed and the cat back sports system shouldn't need to be modified.

Cheers

Greg

We don't do any for the 5.0 litre. I would use a set of Pacemaker.

Cheers

Greg

[Count Grantleyish]

Thanks Greg and I'm beginning to think I'd better off moving on with my VX2 into something modern like VE, simply cos they respond to mods better plus newer chassis.

Oh and another question for you, how restrictive are VE HSV headers? Every time I tried to ger answer, people dribble stuff like brand x is the best followed by another person saying brand y is the best blah blah.

I know I can search/ask these holden/hsv forums but I can't spend more than 30 seconds before punching the laptop cos I can't comprehend what they are saying haha.

On the VE, the pipe into the cat is only 2" or 2.25" at best and it comes from a vertical angle into a chamber. This creates turbulence and a big restriction as the gas has to change direction to horizontal to pass through the tiny 600cpsi holes in the cat and exit through a 2" hole. Therefore whether it is the HSV headers or the Holden Manifolds, it still has the same restriction.

We do a set of 4>1 1-7/8" stainless extractors that are tight to the engine and finish in 3.5" with an internal spike in the collector. Our Ballistic 100cpsi Racing cat is a 5" body which is 3.5" inlet and after the gas passes through the substrate it tapers down to 3" pipe size. We offset the body of the cat upwards, so it doesn't hang low, even on lowered cars. No O2 harness extensions are needed and the cat back sports system shouldn't need to be modified.

Cheers

Greg

Thanks Greg.

[AngryRB]

Im gonna get some TRI-Y's and 100cell cats, I don't want to risk the car turning into a sloth at street speeds, I may as well leave the catback alone and see if the sound changes afterwards, Not intending to spend $10k plus on this, its just for some daily fun and sound.. The sureflow does sound pretty good, but will give this DF catback a chance to shine first..

I had a go at taking out the short segments of 2inch pipe a few days ago, started cutting up those front pipes, I found a 2inch pipe within the front 2 1/4 inch pipe, its surrounded by steel wool, bloody hell that's sneaky shit, so I welded some 2.5inch pipe from the manifold to the cats and cleaned out a cat, I know bad idea. It was pretty hard for an amateur with a MIG welder, wont do that again, but the car has picked up some sound so im looking forward to getting some extractors and cats now...

Edited March 20, 2015 by AngryRB

[butterfly effect]

If you check out my stage 3 active system , www.activeexhaustsystems.com.au you can see the advantages. Drones are usually caused by high flow systems that are in cruise mode with low gas flow rates. With my kit when in low performance mode there is a generated back-pressure , regulated. The drone is gone. When tripped into high performance mode by tps switching max flow is achieved. It is a closed loop system which is fully adjustable. There is no loss of performance only less noise most of the time and no drone.

[Thunder]

Yes, the valves have their uses, and in some vehicles (Bridgeported rotaries, etc) it is the only way to keep them quiet.

How much would a dual 2.5" cat back system be with your setup?

I'm guessing it is pretty expensive by the time everything is fitted, wired and plumbed up.

These cars aren't too hard to stop the drone.

[AngryRB]

I can imagine the car would sound awesome with the valves in place just behind the middle mufflers because removing the rear pipes and resonator made it sound awesome..

Greg, what extractors and size do you have on this Green VY SS, https://youtu.be/2PfB7qhRHts , sounds like porn.

[butterfly effect]

My stage 3 kit is $1200. I am looking for a big company to manufacture and market the product hopefully US. I have a lj torana fitted with a 500 hp chevy , dual 3" exhaust fitted with my stage 3 kit. I am going to make a demonstration video soon to explain the operation. Hyperflow Technologies , now dead , used to market it. Not many people know about it. I sold some to Evotechnics Motorsport in Abu Dabi. One of the good features of this system versus bimodal mufflers is when you want to swap vehicles you can remove the kit .

[AngryRB]

Found a Youtube clip where they compare header size, its a much bigger motor but the comparisons are interesting because the bigger headers don't loose any power. Its good to see some analysis on a dyno to show something about headers size.

4 into 1's are pretty sexy pipes

https://youtu.be/01bXPNy1Yn4

Edited March 22, 2015 by AngryRB

[Plattsy]

what makes it better than stage 2 and worse than stage 4?

[zebra]

Found a Youtube clip where they compare header size, its a much bigger motor but the comparisons are interesting because the bigger headers don't loose any power. Its good to see some analysis on a dyno to show something about headers size.

4 into 1's are pretty sexy pipes

https://youtu.be/01bXPNy1Yn4

Not entirely true

Quite a few people have gone to bigger pipes...or spent a fortune on have custom stepped headers made etc etc

only to loose a few 10ths at the strip over off the shelf headers