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Ls1 sedan diff gearing ratio

TI3VOM

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Dont beleive i said i tuned the car to rev lower keyboard warrior. But i guess you just needed to be there to understand what i mean...or maybe you could of told the tech how to do his job. In My opinoin i already said i would go a 3.7....so nothing new there.

This is the last thing I may post about this particular topic you brought up, your tuner cannot tune your car to lower the RPM of your engine after a mechanical change has been done. The particular change that you did (changing diff gears) makes your rear wheels turn 3.46 times to every 1 rotation of the engine as opposed to 3.07:1, what this does is change what speed you need to rev the engine at to maintain the same speed as previously, in other words you need to rev your engine more!
This cannot be changed by a tune.
 

MrSirWantalot

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ffs mate look & read what i wrote...like seriously you sound like a broken record. Where did i state that i tuned the car to speciffically to lower the revs? like mate read it before you comment!. Just for the ppl who are a little slow. I got diff changed, I got a mafless tune, while i got a mafless tune the tech recalibrated the speedo to suit, wound up the pressure for the gear changes (harder if im not mistaken) whilst doing that he did whatever he did to lower the revs by 300 in top gear cruising. Now i dont know how to explain it better than that Im not a mechanic as i guess you must be. If ur close enough for me to show u what i mean id be more than happy to prove it. And thank you for the leason in the math of diff gears, but nothing new there either. Does anyone else want to go around in circles & say i said something i didnt??
 

Jesterarts

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Dont beleive i said i tuned the car to rev lower keyboard warrior. But i guess you just needed to be there to understand what i mean...or maybe you could of told the tech how to do his job. In My opinoin i already said i would go a 3.7....so nothing new there.

To refresh your memory, here is where you said it:

I changed my diff from a 3.07.1 to a 3.46.1 & it took the revs upto 2300 approx from 1800, but because I do alot of hwy driving I asked the tech that tuned my car to give me less revs in top gear (auto) witch he did & @ 100kph it sits on 2000. Ideally if I didnt do as much hwy driving I would of went & got a 3.7.1 diff out of a manual HSV. A 3.46 is good for standing starts & towing witch I dont think you will be doing with ur mods...unless you wanna pull the trailer apart :). I think the speed recal is all you should need to do!

and here:

I went from around 1800 (3.07) to 2300 with the (3.46) diff in, if thats not right well...... i cant explain....... So at 2300 @100 kph The tech asked me if i would like less revs in top gear witch I said yes witch once he done brang the revs down to 2000 at 100kph (or 2023 to be exact) . Anyway we have drifted off away from the question matqld asked....& in my opinion Id use a 3.7 out of a man hsv. :). Btw this was all done whilst he was plugged into the ecu, & yes he did change trans pressure, for harder changes i suspect!?

To achieve a reduction of rpm like that you need to swap the diff out. A reduction of 300rpm is quite substantial. If I was to change from the 4.11's I currently have to 3.73's I would only see a rpm decrease around the 200 mark. So if we used that as a baseline, in order to achieve a 300rpm reduction in top gear would require you to go form 3.46 to 3.08.

Maybe the tech just swapped your diff back? :p
 

MrSirWantalot

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Nah, just read my last post...surely that cleared it up!.....anyway....its getting old & plus ur too far away to prove what im trying/tried to say/mean.
 

DLFHUB666

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I think this fella needs to change his name to SIRFAILSALOT as every post that i have seen from him is 'winning' that is sarcasm if you didnt know. An to the OP 3.73 would be ideal.
 

MrSirWantalot

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sorry, what am i winning? And to think all i did was try to give my opinion.

"Do not argue with an IDIOT.
He will just drag you down to his level an beat you with experience".


Ok i wont argue
 

matqld

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hehe thanks guys........ im looking around for 3.73, these are standard from a vx hsv manual right?
I see diff gears (just the pinion and crownwheel) for 599 on ebay new.
But im looking for a complete 2nd hand diff at this stage from a hsv,
Not sure if im right but,
vx 6speed man = 3.46 vx hsv 6peed man = 3.73
So im after 2nd hand hsv 6speed man diff.
So what sort money would i expect to pay for this?

this way ill have an lsd diff.

thanks again guys...........

Hey guys atm my diff is just standard auto 3.07 i think and its not lsd i dont think. i say this because once i held 1 wheel still while turning tailshaft and the free wheel turned. has the "use the high performance oil tag" but thats it.
Sound right? standard executive vx ls1 non lsd? was the lsd diff a factory option in this situation?
 

MrSirWantalot

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Dare I say it :boxing: but yes I had the same diff, was a 3.07 non lsd with that tag as factory standard, LSD was an option only ( I think ). Although mine is a berlina, the LSD was an option only & not standard. Probibly best to ring a diff speacilist & tell him what you want & he'll tell you what the best diff ratio is for ur situation. I rang up a year or so ago & the price I was given for a 3.73 was $750...but i didnt shop around too much! & went for the 3.46 lsd out of a manual maloo ute witch cost me $500 :banstick:
 

Munz

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hehe thanks guys........ im looking around for 3.73, these are standard from a vx hsv manual right?
I see diff gears (just the pinion and crownwheel) for 599 on ebay new.
But im looking for a complete 2nd hand diff at this stage from a hsv,
Not sure if im right but,
vx 6speed man = 3.46 vx hsv 6peed man = 3.73
So im after 2nd hand hsv 6speed man diff.
So what sort money would i expect to pay for this?

this way ill have an lsd diff.

thanks again guys...........

Hey guys atm my diff is just standard auto 3.07 i think and its not lsd i dont think. i say this because once i held 1 wheel still while turning tailshaft and the free wheel turned. has the "use the high performance oil tag" but thats it.
Sound right? standard executive vx ls1 non lsd? was the lsd diff a factory option in this situation?

if your car was v8 from factory its got an lsd, your diff is probably getting a bit on in age and wear and needs to be reshimmed to get that LSD feeling like it should

3.73 or 3.91 should be your choice
 

MrSirWantalot

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if your car was v8 from factory its got an lsd, your diff is probably getting a bit on in age and wear and needs to be reshimmed to get that LSD feeling like it should

3.73 or 3.91 should be your choice

Not exactly true. Mine is a v8 vx berlina & it had a 3.07 non lsd, all it had on the tag was high performance & yes it was the original diff according to VIN number. But anyway mat is better off ringing a diff speacilist, that way you should'nt get the bum steer.
 
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