Quest for acceleration

[SAF_Capri]

Will a 4.1 diff with LSD make much of a difference over the std 3.75 i have in my capri?

 

will a lightened flywheel help too?

 

Top end power doesnt bother me, im just after impressive acceleration to 70-mph.

[Copey]

the LSD will help with traction and gettin the power down

[SAF_Capri]

cheers, i will be investing in the best recommended road tyres too, low profile on 15s is what im looking at in the future, 9" rear, 8" fronts.

[Copey]

i hear good things about Toyo Proxes

[Noodles]

i hear good things about Toyo Proxes

 

They are stickey but wear out well quick, I was goin though 2 sets a year on another car, depends how much you use it I suppose.

[SAF_Capri]

will mainly be sunny days ... i dont mind spending the money to get the desired effect, as long as its worth it..and if it suddenly rains i still have grip!

[Vista]

Before you go too low on your Diff ratio Shane, remember how far we have to drive from down here to get anywhere for big shows and meets etc, It's a real ball ache when driving any distance.

[SAF_Capri]

i hope to have the car proper show standard next year, so using this winter to iron out any other niggles/improvements.

 

I found the car revved at 2.5k at 70 on the way to exeter, so is a 4.1 really going to rev a great deal more?

[Vista]

i hope to have the car proper show standard next year, so using this winter to iron out any other niggles/improvements.

 

I found the car revved at 2.5k at 70 on the way to exeter, so is a 4.1 really going to rev a great deal more?

 

2500? what gearbox ratios, final drive ratio and tyre size do you have in it?

[SAF_Capri]

standard type 9, with standard capri laser wheels, and tyres, the diff is 3.75 ... i was suprised how low it is, but its true, which got me thinking about a 4.1 diff, ...i am going for 15" wheels in the new year.

[Vista]

Something's not right there, either you aren't doing 70 or you're not doing 2500 rpm. what's the tyre size?

[SAF_Capri]

couldnt tell you, the revs check against the tuner and mot, and the speedo is obvisously provided by the box, so could it be the box? it does 70 in second ..that normal? ..that was with the old pinto lump.

[Vista]

Assuming that 185/70/13 is the standard tyre size and you have a type 9 and 3.75 final drive ratio, your revs to speed should look something like this. As you can see, 70 should equate to something like 3100 - 3150. It's more likely that you have the wrong speedo drive in the box for your dash. Do you have a sat nav you could compare your road speed to?

 

 

[SAF_Capri]

Cheers scot, i can get to about 25mph in 1st, any ideas on what you think it could be? or should i just live with it, and go for a 4.1 for that extra bit of acceleration?

[SLEEPY]

Before you go too low on your Diff ratio Shane, remember how far we have to drive from down here to get anywhere for big shows and meets etc, It's a real ball ache when driving any distance.

 

I can agree there, i've got a Quaiffe box and a 4.4 diff and it's a nightmare on a long run (good fun though).

Mine would be screaming it's nuts off to get to 70 in 2nd,

Try a power run on a rolling road that'll give you mph & rpm

[SAF_Capri]

will get one done over winter, is there anyone good around plymouth tho?

[Vista]

Here it is again with a 4:1 CWP this time

 

 

As you can see, 70 puts you at 3500rpm but if you've designs on maintaining 80 - 85 motorway speeds, then your economy will suffer a lot as will your eardrums as you'll be cracking around 4000 rpm.

 

Your car your call though and it depends what use you have planned for it, a 4:1 will certainly improve your point to point squirt and if you're planning on fitting bigger wheels and tyres that'll drop your gearing down again anyway.

[SAF_Capri]

definately going 15s, so as you say that will drop it back down, i dont mind the noise on the motorway, it is what it is a loud capri with a vauxhall engine

 

any thoughts on lightened flywheel to help acceleration too scot?

 

hows the van coming along, i enjoy reading your thread.

[Vista]

Yes a lightened flywheel will help though I doubt you'd notice much (if any) difference behind the wheel.

 

15" wheels will only change your gearing ratio if the tyres you fit on them have a different rolling radius to the originals.

[SLEEPY]

15" wheels will only change your gearing ratio if the tyres you fit on them have a different rolling radius to the originals.

 

He's right by changing the wheel size you could find yourself back in the same position or too far the other way, try one mod at a time and see what you prefer.

[SAF_Capri]

so by going to a 4.1 i could gain acceleration, but then by going to 15s i could loose it? ...yet if i fit a tyre to equal-ish the rolling radius of the 13s then i will still gain the benefit of the diff?

[Vista]

so by going to a 4.1 i could gain acceleration, but then by going to 15s i could loose it? ...yet if i fit a tyre to equal-ish the rolling radius of the 13s then i will still gain the benefit of the diff?

 

Exactly, in fact if you select a 15" tyre that has a smaller rolling radius than your original 13" ones you'll improve your pick up further, a larger one will slow it down.

 

Corr don't they teach you greenies nothing at Collinggrad?

[SAF_Capri]

Im a pinky! and collingrad it certainly is, what a hell hole..no wonder it was a pig farm!!

 

more research required then for winter when these mods get done.

[Vista]

Im a pinky! and collingrad it certainly is, what a hell hole..no wonder it was a pig farm!!

 

more research required then for winter when these mods get done.

 

Pinky, I stand corrected. I've been away from the game nearly 8 years now.

[SAF_Capri]

youve got to always play the game

 

best get saving then, i take it you recommend fostek for axle work?