Torque improvement

SeanDezart

SeanDezart

Well-Known Forum User
What modifs can one (inexpensively) do to improve the torque on a standard car ?
BMW throttle body ?

Has anyone tried using an LD crank to get 3 or 3.1 litres in a ZX ? If one touches anything, can the standard injection cope with increased demands ?
If not, what are the alternatives ?
I suspect it can't but can one replace the injection system with a more modern one ?

Thanks

ps Is it a real gain to replace the variable assistance re-circulating ball steering system with the rack and pinion one ?
 
Hi Sean ,, if your not over concerned about top end speed then I would say the cheapest way to improve torque at the wheels ( where it counts ) is to lower the gearing ratios,,, probably the cheapest way, but you loose on top end speed. I have amazed myself with some cars just by loosing an inch in drive tire diameter, makes a hell of a difference! And if you know a good supplier it shouldn't be 2 hard to actually change rear diff gearing. ;) I Speak with north american tongue though,,don't really know nissan gear availability!
 
Me again,, regarding the steering issue. If you mean to loose the power steering pump, then yes it is a gain in HP. Not much, maybe about 2.5 to 5 hp depending on the car, but probably not worth the extra effort,, unless you want great big Arnie type biceps ! :D
 
Changing the steering was not to gain hp, some say the road feel is better with rack and pinion but I like the sound and facility of speed sensitive power steering. Does the rack and piniuon system have this ?

No, I don't want to lose top end speed - a 280 isn't exactly a rocket and I don't want to increase the revs (they're also thirsty).

I was thinking of something without resorting to turbocharging. Now I'm here, is this 'easy' to do, meaning relatively inexpensive ?
 
Hi
if you do find an inexpesive way of making your 280z quicker let me know because my300zx z31 is also dog slow , if anyone does know of someone that can change the diff ratio's let me know cos it would'nt bother me losing top end

thanks neil :)
 
Did I say I had a 280ZX ? If I get any info I'll certianly share it but where are all the 280ZX fans ?
 
Ive sold my 280 as you already know and now ive got a 300.
Steering box to rack is just a straightforward parts swop. If it wasnt then i wouldnt have been able to do it. You need the whole x member and the whole column, et Voila! its done!
Best diff is the one from the late manual. 3.9. Virtually impossible to find late manuals in UK as they were nearly all autos
 
Straightforward or not Pete, is it worth the expense and time to change ? Does the 280 have a 3.7 diff then ? Or is it an 'inferior' 3.9 ?
 
'79 - '81 280ZX manual have 3.7 R200, facelift '82 - '83 manual have 3.9 R200. Why do you imply a 3.9 would be "inferior"? Matched to the appropriate overdrive gear in the gearbox it will give a bit of extra grunt in 1st to 4th and still cruise at the same rpm in 5th as the 3.7.

280 engine responds well to bigger throttle body (still available as a "bolt-on" specific part, no need to adapt BMW), header exhaust manifold and performance exhaust (keep the back pressure reasonable, though) and a K & N or similar induction kit. Fuel pressure response can be improved with a rising rate regulator. Any more than this and the standard injection control module becomes inadequate and will probably lean out at the top end of the rev range. If you want to spend a little more, then a mild cam kit will improve matters, but the car will really need an alternative ECU.

Oh, and buy a 2 seater to keep the weight down..............

The rack and pinion conversion is the best thing you can do to improve the driveability of the '79 to '81 cars. It is also speed sensitive with correctly weighted feel, i.e. power assisted, not just powered. The steering box is horrible and has a "dead" spot in the centre when worn that makes the car unpredictable and twitchy.
 
Thanks Mike,

Didn't mean to infer 'inferior' 3.9, thought there were only 3.7s in 280ZXs and that the 3.9 was, let's say, different to that in 240Zs !

So what torque improvement can one expect from the mods you've proposed, without changing the camshaft ?

And is a 2 seater THAT less heavier than a 2+2 ?
 
I don't have any absolute figures for torque improvements although the owner of the car may still have some of his dyno sheets - I'll check with him...

And is a 2 seater THAT less heavier than a 2+2
Click to expand...

About 200lbs lighter in standard UK trim.
 
I await your response before considering the add-ons you suggested ! Over here, a car should be kept in standard form but what you were proposing could be discreetly done and greatly improve overall driveability !
 
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