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Just Got Spanked...

6K views 37 replies 14 participants last post by  xdc351 
#1 ·
heya all
just went driving with a mates stocker VX V6 ecotec.. and well we were at the lights and he beat me by around 1 car length, i was literally shocked and had to pull over... wtf is going on with this world.. how come my car is so slow???? its got a 302 nice cam toploader, but it had 2.92's in it, so im guessing thats holding it back, getting the nine inch LSD stuck in with 3.5's so you rekkon i could gain even more than 1 car length to beat him? man thats crap (i dont have extractors) its been overbored .020" i think with new pistons i just cant believe that

:AAHHH: :AAHHH: :AAHHH:

tell me wots my weakest link? (and dont say my 302 lol):p
 
#2 · (Edited)
More than likely it is the tall diff that isn't doing you any favours. When I Drag Raced my XB GT with a 2.75:1 diff (Old standard Engine) it pulled 15.8 @ 90 mph, compared to my EF XR6 which did 15.1 @ 89 mph. So as you can see, while the GT had more top end than the XR6, the 3.45:1 Diff got it off the line a hell of a lot quicker (probably a lot more than one car length off the line).

When I had the 2.75:1 Centre replaced with a 3.25:1, the Quarter Mile time dropped to 15.4 (still at 90 mph) so you can see the difference the change in diff ratio made.
 
#3 ·
i know the feeling of trying to race somebody with 2.92 diff gears and with a manual,
if you want it to be quick drop in a set of 3.5's i looked around for a borgwarner diff out of a ute, just to try the ratio's, or just go and get a set of 3.9's for your 9inch, it will scream at 100k/h but it will get there very fast and no doubt leave most your other cars back at the set of lights. how hard does your 302 rev?
 
#5 ·
it only revs to 5000 grand but thats screaming aswell, as soon as i get out of school a 351 crank is going in plus all the other goodies, im getting the nine inch with 3.5's on wednesday arve, plus retung springs and added and extra leaf plus new bushes is gonna cost me 1745 bux... (9 inch all new bearings clutches etc) so hopefully she will go a fair bit harder
 
#7 ·
standard manifold (2V i think) and a small holley... 465 i think but it has vac secs... im gonna chuck the 600 back on there and see how it goes (had jetting problems with it ill see if i can tune it nicel)
 
#8 ·
XDman said:
standard manifold (2V i think) and a small holley... 465 i think but it has vac secs... im gonna chuck the 600 back on there and see how it goes (had jetting problems with it ill see if i can tune it nicel)
I think the 465 would work better. 600 is pretty big for a 5 Litre Engine.
 
#9 ·
yeh thats why we took the bigger one off in the first place, but still doesnt let a shitty v6 holden beat my falcon :(
 
#11 ·
nah its a 4 barrel and i cant recall wot the 600 is its in the shed and i cant be bothered going to look at it at the moment but its always had a 4brl carby on it so i dunno if its 2v or 4v :( theres pics of it under my name in the gallery so if u can tell by looking at it please do :)
 
#12 ·
That is wierd, I would of thought you would cane a VX with a 302 and a toploader.
I have the same 2.92 ratio and its a single spinner along with an auto trans and I get the biggest jump off the line against my mates VR and VS V6 commies and its the same against Vt/X's too. I have a 351 though.
Im on my P's too and havent been pulled up yet, if you see what Im getting at. ; ) My car didnt even come standard with a V8 and ive had no dramas yet. Its been about 5 months since the engine change.

Let us know how the diff change goes. I want to do the same before the next drag meet.
Dan
 
#13 ·
Sorry, but a stock VT holden would put out more power than a stock carbied 302 in an XD (with all the pollution gear). I think the V6 commies have around 151kw, where the 302 had more like 130 to 140-odd. Don't be too upset, once you get the 351 crank in, that should make up some of the difference.
 
#15 · (Edited)
i think the old girl is a bit tired... gonna perk it up with some alloy heads 351 crank new pistons keep the 302 rods and a nice cam cant forget something like a holly 600-700DP... should stomp all over just about any holden :p (this is after i get out of school and get a full time job) wot price would i be looking at?? around 3500 for alloy heads?? crank and woteva else i need i wouldnt have a clue for pricing, if you could help me out i can start saving now :bigeyes:
 
#17 ·
get the heads tickled, bit of a cam, exhaust,gearing, 351 crank... you'll eat a v6 as long as the motor's healthy...

Don't worry about alloy heads... you can make 450+HP on a streetable motor with the heads you have now (302C closed chamber quench heads), unless you plan to run low 12's in the near future... Your $5000 or so is better spent elsewhere for now...

shane
 
#19 ·
falcon coupe said:
While we are talking about diffs, i was thinking of changing the ratio in my 9 inch, i think it has flat 3:0, it sits on 3000rpm at 100klm, does that sound right for a toploader ?
Sounds more like a 3.5:1 if it is doing 3000 RPM @ 100 kmh.
 
#23 · (Edited)
First, check for a tag, you never know your luck.

Failing that try the below:

Chock the front wheels, jack the rear of the car up and put axle stands under the diff housing. Mark the wheel at the top and the wheel arch with a piece of tape. Take off the handbrake and put in neutral. Then have someone watch the wheel while you turn the tailshaft 20 times by hand.

If the tape passes the same point approx 7.2 times its a 2.77:1 ratio, 6.6 turns is a 3.00:1 and 5.7 turns is 3.5:1. I'm sure you can work them out though!

20 divided by rotation=ratio

A couple of notes though. Always do at least 3 tests, test both wheels and average the 3 to get your rotation figure. Also a stuffed LSD can impair results.

Hope this helps
 
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