dumping exhaust at the diff
Started by
makka
, May 11 2006 04:52 PM
61 replies to this topic
#26
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Posted 16 May 2006 - 07:26 PM
got twin 2.5 inch dumpers on mine, i have the dump tips turned at 45 degrees, sounds really good, especially with the big stall and big cam
#27
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Posted 16 May 2006 - 07:53 PM
I'm serious. 6" rims were an option, so the widest allowed in VIC is 7". This can vary from state to state.You serious chopper? Well thats just screwed. The list of things I should have engineered are beginning to mount up.
#28
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Posted 16 May 2006 - 08:43 PM
I run twin 2.5" pipes mandrel bent over the diff, its 9" diff, standard wide fuel tank and its lowered 2.5".
If it were press bent Id have more room, as the mandrels dont squash.
Just go 2 1/4" pipes over the diff, its doable just takes time and patience.
If it were press bent Id have more room, as the mandrels dont squash.
Just go 2 1/4" pipes over the diff, its doable just takes time and patience.
#29
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Posted 16 May 2006 - 09:32 PM
I run twin 2 and a half under my diff because i had the same prolems with over pipes hitting my diff housing/floor. They even had clearance enough beside the tank for a 4 inch resonator each side. Still bloody loud. I had diff dumps for ages untill cheif wiggum had a cry one morning and stickered me for being too loud. Miss the rumble it made so much
#30
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#31
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Posted 16 May 2006 - 11:39 PM
I have my exhaust finishing just before my diff also. I had a single 3" under the diff, and when i jack the back up it hit the exhaust (it broke an exhaust bracket, because i didnt know at first!) I had to cut the exhaust short as i needed to replace the diff, and couldnt do it with the exhaust there!!!
Also, if your exhaust does go under your diff, be careful when getting new tyres, as most places will lift the whole car off the ground, meaning that the diff is sitting heavily on your pipe/s. possible doing damage!
Im thinking of getting my exhaust fixed and getting the exhaust blokes to add a flange, in the case of diff changes.
Also, if your exhaust does go under your diff, be careful when getting new tyres, as most places will lift the whole car off the ground, meaning that the diff is sitting heavily on your pipe/s. possible doing damage!
Im thinking of getting my exhaust fixed and getting the exhaust blokes to add a flange, in the case of diff changes.
#32
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Posted 17 May 2006 - 07:45 AM
I had a single 3" in my LJ under the diff and the first time I jacked it up from the diff I was unaware it would touch and it broke the rear exhaust mount.
I'll probably be going a single 3 1/2" with the new motor but I'll try to split it to twin 2 1/2" before the diff so it can go over, the 3" under the car stood out like dogs balls.
I'll probably be going a single 3 1/2" with the new motor but I'll try to split it to twin 2 1/2" before the diff so it can go over, the 3" under the car stood out like dogs balls.
#33
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Posted 17 May 2006 - 09:17 AM
Just one small point with exhausts - Bigger is not always better...Too large can rob you of horsepower..
Talk to any exhaust specialist, he will ask you what is done to your motor and then assuming he knows his apples he will advise you on the correct size etc.
Cheers
Herne
Talk to any exhaust specialist, he will ask you what is done to your motor and then assuming he knows his apples he will advise you on the correct size etc.
Cheers
Herne
#34
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Posted 17 May 2006 - 09:58 AM
Interesting!
Did I see some 10 bolt /bw diffs in those early shots?
Herne?
Did I see some 10 bolt /bw diffs in those early shots?
Herne?
#35
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Posted 17 May 2006 - 10:38 AM
Hi The Baron
Yes you certainly did, I have a 10 bolt Salisbury diff in my car. The floor pan is LX and not UC it is the diff mountings that have been altered. Struggler from this forum was kindly over at my place yesterday helping me out. Being under the car he spotted the diff and had a close look at it. His words were it is extremely well done.
Thanks for noticing.
Cheers
Herne
Yes you certainly did, I have a 10 bolt Salisbury diff in my car. The floor pan is LX and not UC it is the diff mountings that have been altered. Struggler from this forum was kindly over at my place yesterday helping me out. Being under the car he spotted the diff and had a close look at it. His words were it is extremely well done.
Thanks for noticing.
Cheers
Herne
#36
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Posted 17 May 2006 - 11:51 AM
Are you sure about that CHOPPER? I'm not sure if that's correct. I've heard otherwise from some reliable sources.8" rims are illegal on any Torana, unless it has an engineers cert. Some states will allow 7" rims.
You'll find that you can go up to an 8" rim on a Torana. If you speak to an engineer he'll tell you that he will support up to a 10" rim on a full floater and that up to 8" rims on a normal diff are OK for a Torana.
Liam, you will find that it's maintaining track width within a certian tollerance you should keep in mind, but on your car it should be OK anyway.
Herne: I have heard the "bigger is not better" with exhausts from heaps of people and that they can rob your system of power. I can understand that you need some backpressure from an exhaust and balancing in a dual exaust for the scavaging effect of gasses etc and I've heard a lot of different conflicting opinions from various exhaust "specialists". BUT why is it that when you dump the exhaust all together you find a horsepower gain? This has always confused me. Can somebody please explain?
Also, If you go under the diff with your exhaust, roughly how much clearance btw the top of the exhaust and the bottom of the diff should you have (I know it depends on how much diff travel you have but I just want to know roughly)
#37
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Posted 17 May 2006 - 12:21 PM
I have also got a disc brake 10 bolt under mine Baron, pics on page 2 of the thread, the mounts on the diff have not been modded though.....
#38
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Posted 17 May 2006 - 08:23 PM
100% sure. For the past 22 years ( and possibly longer ) the guidelines in VIC have been 1" wider than the widest rim optioned from the manufacturer. 6" were an option, so 7" is the maximum.Are you sure about that CHOPPER? I'm not sure if that's correct. I've heard otherwise from some reliable sources.8" rims are illegal on any Torana, unless it has an engineers cert. Some states will allow 7" rims.
You'll find that you can go up to an 8" rim on a Torana. If you speak to an engineer he'll tell you that he will support up to a 10" rim on a full floater and that up to 8" rims on a normal diff are OK for a Torana.
If you speak to an engineer, it means you are getting an engineers cert. That makes it legal.
#39
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Posted 17 May 2006 - 08:25 PM
That's why you open your mouth and tell us. We rather you tell us before we start the job, rather than we find out the hard way.Also, if your exhaust does go under your diff, be careful when getting new tyres, as most places will lift the whole car off the ground, meaning that the diff is sitting heavily on your pipe/s. possible doing damage!
#40
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Posted 18 May 2006 - 11:29 AM
No, that's not what he meant CHOP, he was saying that it wouldn't need to be on the certificate.100% sure. For the past 22 years ( and possibly longer ) the guidelines in VIC have been 1" wider than the widest rim optioned from the manufacturer. 6" were an option, so 7" is the maximum.
Are you sure about that CHOPPER? I'm not sure if that's correct. I've heard otherwise from some reliable sources.8" rims are illegal on any Torana, unless it has an engineers cert. Some states will allow 7" rims.
You'll find that you can go up to an 8" rim on a Torana. If you speak to an engineer he'll tell you that he will support up to a 10" rim on a full floater and that up to 8" rims on a normal diff are OK for a Torana.
If you speak to an engineer, it means you are getting an engineers cert. That makes it legal.
Do you have any info, internet links to verify this?
#41
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Posted 18 May 2006 - 04:32 PM
I have 3 and half inch twin exhaust over the diff, had the floor pan modded a bit but when it was stock we had twin 3 inch over as well with a 9 inch rear and it did not touch. You can do it with mandrel bends and patience. Plus rego and police like it a lot better.
#42
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Posted 18 May 2006 - 07:05 PM
I had to relocate all the pollution gear to the centre of the diff tunnel, most people would remove it but I need to get my car engineered and scrutineered for rego.I have 3 and half inch twin exhaust over the diff, had the floor pan modded a bit but when it was stock we had twin 3 inch over as well with a 9 inch rear and it did not touch. You can do it with mandrel bends and patience. Plus rego and police like it a lot better.
The key is you need a shitload of bends.
#43
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Posted 18 May 2006 - 08:33 PM
6 page pdf.No, that's not what he meant CHOP, he was saying that it wouldn't need to be on the certificate.
100% sure. For the past 22 years ( and possibly longer ) the guidelines in VIC have been 1" wider than the widest rim optioned from the manufacturer. 6" were an option, so 7" is the maximum.
Are you sure about that CHOPPER? I'm not sure if that's correct. I've heard otherwise from some reliable sources.8" rims are illegal on any Torana, unless it has an engineers cert. Some states will allow 7" rims.
You'll find that you can go up to an 8" rim on a Torana. If you speak to an engineer he'll tell you that he will support up to a 10" rim on a full floater and that up to 8" rims on a normal diff are OK for a Torana.
If you speak to an engineer, it means you are getting an engineers cert. That makes it legal.
Do you have any info, internet links to verify this?
http://www.vicroads....dsafe/VSI 8.pdf
Page 3.
Section 8.
#44
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Posted 19 May 2006 - 11:42 AM
I've read this before,
it says in section 8:
It's my understanding that the L34 A9X came out with 14x7 inch rims, GTS rims and so this is an option for the LX series. Therefore you can go up to 8 inch rim on an LX (or LH). You must have been confusing this with what you've been told for the UC.
You can legally use an 8" rim on an LX Torana as long as you do not alter the track width by 25mm (you'll find this in section 6). And you generally do this by making sure that the rim is centred.
This is why I've been told that you don't require a engineers certificate and if you do engineer the car they wont mention the 8" rims on the certificate. I've been told this as I have 7" rims and want to go to 8" rims later on and I enquired about it thorougly.
8" rims can hold 245 and 255 tyres, whereas the 245 can go under a sedan with ease and a 255 will usually fit snugly under a Hatch (they usually have a bit more room I find)
If you go any larger than 8" rims on a Torana, like 10" rims, you have to use full floaters on your diff and have it engineered with a certificate.
Not trying to be a smartass by contradicting you here CHOP, just trying to create peace of mind for various forum members.
Anyway, getting back to the topic, can anyone shed some light on what I asked before?
it says in section 8:
*The width of any replacement rim must not be:
� - more than 25mm greater than the widest wheel specified by the vehicle manufacturer for that model or vehicle series.
It's my understanding that the L34 A9X came out with 14x7 inch rims, GTS rims and so this is an option for the LX series. Therefore you can go up to 8 inch rim on an LX (or LH). You must have been confusing this with what you've been told for the UC.
You can legally use an 8" rim on an LX Torana as long as you do not alter the track width by 25mm (you'll find this in section 6). And you generally do this by making sure that the rim is centred.
This is why I've been told that you don't require a engineers certificate and if you do engineer the car they wont mention the 8" rims on the certificate. I've been told this as I have 7" rims and want to go to 8" rims later on and I enquired about it thorougly.
8" rims can hold 245 and 255 tyres, whereas the 245 can go under a sedan with ease and a 255 will usually fit snugly under a Hatch (they usually have a bit more room I find)
If you go any larger than 8" rims on a Torana, like 10" rims, you have to use full floaters on your diff and have it engineered with a certificate.
Not trying to be a smartass by contradicting you here CHOP, just trying to create peace of mind for various forum members.
Anyway, getting back to the topic, can anyone shed some light on what I asked before?
I have heard the "bigger is not better" with exhausts from heaps of people and that they can rob your system of power. I can understand that you need some backpressure from an exhaust and balancing in a dual exaust for the scavaging effect of gasses etc and I've heard a lot of different conflicting opinions from various exhaust "specialists". BUT why is it that when you dump the exhaust all together you find a horsepower gain? This has always confused me. Can somebody please explain?
Edited by TORANR AMORE, 19 May 2006 - 11:50 AM.
#45
Dr Terry
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Posted 19 May 2006 - 01:41 PM
Hi Guys.
AFAIK the L34/A9X rims are 14 x 6 not 14 x 7.
I'm with CHOPPER, it's same in NSW 1" increase over the maximum factory rim, so that would make 7" the max.
Dr Terry.
AFAIK the L34/A9X rims are 14 x 6 not 14 x 7.
I'm with CHOPPER, it's same in NSW 1" increase over the maximum factory rim, so that would make 7" the max.
Dr Terry.
#46
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Posted 19 May 2006 - 01:58 PM
Re QUOTE
I have heard the "bigger is not better" with exhausts from heaps of people and that they can rob your system of power. I can understand that you need some backpressure from an exhaust and balancing in a dual exaust for the scavaging effect of gasses etc and I've heard a lot of different conflicting opinions from various exhaust "specialists". BUT why is it that when you dump the exhaust all together you find a horsepower gain? This has always confused me. Can somebody please explain?
Normally you make more horsepower when you dump the exhaust, but if you have a good functioning exhaust you tend to loose Torque and gain horsepower. Torque is what pulls you along.
I have heard the "bigger is not better" with exhausts from heaps of people and that they can rob your system of power. I can understand that you need some backpressure from an exhaust and balancing in a dual exaust for the scavaging effect of gasses etc and I've heard a lot of different conflicting opinions from various exhaust "specialists". BUT why is it that when you dump the exhaust all together you find a horsepower gain? This has always confused me. Can somebody please explain?
Normally you make more horsepower when you dump the exhaust, but if you have a good functioning exhaust you tend to loose Torque and gain horsepower. Torque is what pulls you along.
#47
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Posted 19 May 2006 - 02:10 PM
From my research in the past, I've always been told the same thing as well - MAXIMUM rim width for an LH or LX Torana is 7" (1" wider than the standard 6" rim). Vicroads told me this, my engineer told me this. Even when I bought up the whole 'A9X option' thing as mentioned by TORANR AMORE, they said it doesn't count, unless the car in question is an A9X itself. Total crap hey! But that's the way they decided to make the rules. The A9X is an LX Torana right? So it's a rule that really does bug me. Trying to get this point through and talk them around though is impossible, so last time I had to get a RWC, I just presented the car with 14 x 7's all round.
Anyway, just to add my comments on the original topic here - I also have a twin system that runs under the diff housing (so much easier with the droptank and 9" rear-end. Having the tailpipes like this is awesome. I have flanges before the diff, so I can remove them from the car in a few minutes, and swap to dumpers for car events. When the tailpipes are on, there is heaps of clearance to everything, I even have an eletric fuel pump mounted in there too. Plenty of ground clearance (well above legal limit, but this depends how low your rear springs are). Car passed roadworthy certificate and engineering process like this.
Anyway, just to add my comments on the original topic here - I also have a twin system that runs under the diff housing (so much easier with the droptank and 9" rear-end. Having the tailpipes like this is awesome. I have flanges before the diff, so I can remove them from the car in a few minutes, and swap to dumpers for car events. When the tailpipes are on, there is heaps of clearance to everything, I even have an eletric fuel pump mounted in there too. Plenty of ground clearance (well above legal limit, but this depends how low your rear springs are). Car passed roadworthy certificate and engineering process like this.
#48
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Posted 19 May 2006 - 02:23 PM
Re the wheel widths.
Is it enough to say that you can use the max wheel width based on one of the shell variants in a line up having been fitted at the factory with the 6 or is it 7 inch wheels? ..................when the models that had the wider wheels fitted would be clearly identifiable from the build plate(whatever its called?)
I know everyone will perhaps say the body of a four is the same as that of an 8 etc, but will the authorities see it differently?
Is it enough to say that you can use the max wheel width based on one of the shell variants in a line up having been fitted at the factory with the 6 or is it 7 inch wheels? ..................when the models that had the wider wheels fitted would be clearly identifiable from the build plate(whatever its called?)
I know everyone will perhaps say the body of a four is the same as that of an 8 etc, but will the authorities see it differently?
Edited by devilsadvocate, 19 May 2006 - 02:24 PM.
#49
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Posted 19 May 2006 - 02:35 PM
Hi Guys.
The point that devilsadvocate has raised is spot-on. It's not what wheels were available in that shell, because the RTA engineers could rightly point out that an A9X has a different rear axle & different front stubs, so what it has fitted does not apply to normal Toranas.
What the law basically works off is the tyre placard. If the tyre placard says biggest factory rims are 13 x 6, in NSW 14 x 7 is maximum. A 13 x 6 rim was available on non-A9X Toranas anyway, check the tyre placard, in the glovebox.
An A9X has a unique tyre placard that lists the 14 x 7 rims.
Dr Terry.
The point that devilsadvocate has raised is spot-on. It's not what wheels were available in that shell, because the RTA engineers could rightly point out that an A9X has a different rear axle & different front stubs, so what it has fitted does not apply to normal Toranas.
What the law basically works off is the tyre placard. If the tyre placard says biggest factory rims are 13 x 6, in NSW 14 x 7 is maximum. A 13 x 6 rim was available on non-A9X Toranas anyway, check the tyre placard, in the glovebox.
An A9X has a unique tyre placard that lists the 14 x 7 rims.
Dr Terry.
#50
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Posted 19 May 2006 - 03:30 PM
WOW
Guys a fair while back i was on the phone to an engineer here in melbourne(unsure now who it was) and i disscussed my Torana Hatch to him and what i will need to register it legaly, We spoke for a few hours he was top bloke and very helpfull, infact he was building a V8 LJ at the time for himself..
Any way his main concern about my car was wheel width and track dimentions, he clearly told me i can run 8" rims on an LX without the need of an engineers, he also said that its up to the engineer himself what he allows and what he dont.. His words were on the line like " 8" rims i wouldnt bother with an angineer as you can just get a letter from GMH stating that LX A9X came with 7" rims and a Licenced RWC place wouldnt look twice..
Its simple realy, if the cop witch pulls you over feels your car is defective then prepare for a yello sticker even if you have 10 Engineers certs.. As for insurance i wont go down that path as most know what the go is.. The enginner i spoke to told me that anything bigger then 7" the dish has to be centerd so the center is clearly over the bearing so waight is equaly distributed. Were as with a full floater you can run a wider outer dish and still keep safe without too much load on the bearing..
On another note a very good freind of mine is a qualified mechanic and has a RWC licence and he said to me that by the book you can run wide wheels as long as they dont rub on any steering components and affect its full turning cirle and as long as there isnt any excessive tyre exposer and if your tyre sticks out passed the gaurds you will need flares and mud flaps...
Now what do you do? Comply with the vic rds rules as stated in the PDF chopper put up, or not worry if your mechanic and RWC tester pass's it and allows you to get it registerd?
You decide
John
Guys a fair while back i was on the phone to an engineer here in melbourne(unsure now who it was) and i disscussed my Torana Hatch to him and what i will need to register it legaly, We spoke for a few hours he was top bloke and very helpfull, infact he was building a V8 LJ at the time for himself..
Any way his main concern about my car was wheel width and track dimentions, he clearly told me i can run 8" rims on an LX without the need of an engineers, he also said that its up to the engineer himself what he allows and what he dont.. His words were on the line like " 8" rims i wouldnt bother with an angineer as you can just get a letter from GMH stating that LX A9X came with 7" rims and a Licenced RWC place wouldnt look twice..
Its simple realy, if the cop witch pulls you over feels your car is defective then prepare for a yello sticker even if you have 10 Engineers certs.. As for insurance i wont go down that path as most know what the go is.. The enginner i spoke to told me that anything bigger then 7" the dish has to be centerd so the center is clearly over the bearing so waight is equaly distributed. Were as with a full floater you can run a wider outer dish and still keep safe without too much load on the bearing..
On another note a very good freind of mine is a qualified mechanic and has a RWC licence and he said to me that by the book you can run wide wheels as long as they dont rub on any steering components and affect its full turning cirle and as long as there isnt any excessive tyre exposer and if your tyre sticks out passed the gaurds you will need flares and mud flaps...
Now what do you do? Comply with the vic rds rules as stated in the PDF chopper put up, or not worry if your mechanic and RWC tester pass's it and allows you to get it registerd?
You decide
John
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