rpm/s to mph

Post by **sven360** » 02 Mar 2006 10:49 pm

Speedo went west today- so if can't fix this weekend -anyone know what mph per 1000 revs you get in boggo std 360 on 14's?

At a guess I think it may be about 22 per thou in top but anyone know for sure?
Thanks

Post by **petefarrell360** » 02 Mar 2006 11:40 pm

70 mph in 5th in a 360 GLT is just a tad below 3000 rpm if that helps, 90 mph is approx 4000 rpm. I used to know all of the revs to speed throughout all the gears when the same thing happened to me, at first I could wiggle the cable on the back of the hub so the sleeve was rotating again, so had a chance to make the mental note of the speeds until I finally got around to sorting it out!
Pete

Post by **foggyjames** » 03 Mar 2006 09:31 pm

You get an extra 10mph at 4000rpm with my econo-diff

cheers

James

Post by **jtbo** » 04 Mar 2006 12:23 pm

100kph is near 2600rpm with 360GL 3,36 differential
100kph is near 2800rpm with 360GLT 3,64 differential

100kph = 62.1Mph

80kph is near 2230rpm with 360GLT 3,64 differential
80kph is near 2040rpm with 360GL 3,36 differential

80kph = 49.7Mph

That is what math shows for 185/60-14 tyres that has 2,2bar airpressure, 5th gear naturally.

60kph is near 1900rpm 360GL 3,36 differential 4th gear
60kph is near 2000rpm with 360GLT 3,64 differential 4th gear

60kph = 37.3Mph

Hmm, those are speed limits common in finland, I think in UK you have bit different speed limits, we have 80kph at winter on normal 2 lane roads, which we mostly have, 100kph on summer.
60kph is common near cities where is 4 lanes and at city we have mostly 40kph.
Limits are too slow, no matter what they are

Post by **Fuse** » 04 Mar 2006 02:58 pm

GLT has too high diff ratio for my liking.. or it would need a sixth gear on highways.

On long journeys the engine sound starts to annoy when driving ~140kph and rpms are constantly ~3500rpm or over.. GL has much nicer ratios. ~2300-2500 in 100kph and much smoother on high rpms too. GLT gets weird resonances sometimes. Though I think it is because the gear lever support is currently bolted straight on to the body so vibrations go straight in to body..

I haven't yet checked if it is the weldings or the screw which had come off from the torque tube.. Someone has fixed it by bolting whole thing in to the body from upwards..

Not the most subtle way so I should do something about that.

Post by **jtbo** » 04 Mar 2006 03:25 pm

Fuse wrote:GLT has too high diff ratio for my liking.. or it would need a sixth gear on highways. On long journeys the engine sound starts to annoy when driving ~140kph and rpms are constantly ~3500rpm or over.. GL has much nicer ratios. ~2300-2500 in 100kph and much smoother on high rpms too. GLT gets weird resonances sometimes. Though I think it is because the gear lever support is currently bolted straight on to the body so vibrations go straight in to body.. I haven't yet checked if it is the weldings or the screw which had come off from the torque tube.. Someone has fixed it by bolting whole thing in to the body from upwards.. Not the most subtle way so I should do something about that.

Diff ratio is indeed bit two bladed sword, I could use of 3.64 ratio as 3.36 is too long on track and specially for my current engine tuning, I can't use 5th at winter at all as speeds are too slow

You can have my diff ratio if you do the replacing

Post by **Fuse** » 04 Mar 2006 03:33 pm

Hehe. I think I'll try to get that gear leveler thing in order first. And the sunroof, I think that's the biggest cause for noises..

On the other hand it might also be that the GL's ratios could be too low for the GLT with current engine. GL pulls nicely throughout the rev range with much better acceleration than GLT, as GLT doesn't build up much boost at low rpm's.. Dunno what makes the difference as the boost levels are almost the same. GLT has crappy boost side piping though, many turns and the diameter of the pipe changes something like over an inch on the way.. That's a big no no in boost side piping what I've heard. Well luckily those are getting replaced soon with shiny new pipes.. (Yes the shiny paint also adds more hp

)

Post by **foggyjames** » 05 Mar 2006 12:13 am

You have to balance diff ratio against your engine's torque curve. I find the 3.36 rear end to be far too short for the current engine config, and were I keeping it long-term, I'd probably drop a 340 1.4 5 speed diff in there.

cheers

James

Post by **petefarrell360** » 09 Mar 2006 12:28 am

Fuse wrote:GLT has too high diff ratio for my liking.. or it would need a sixth gear on highways.

That's exactly how it feels, the revs are too high when crusing, and lately, it's hit the pocket hard as I've done quite a few motorway miles.
Pete

Post by **SteveP** » 09 Mar 2006 12:31 am

Hmm.. I don't know I think cruising engine speed is fine, most of the other cars I've driven have done 3k to 70mph... so its a general thing.

If the diff ratio was different, giving lower revs to speed - then you might have more trouble overtaking stuff, having to change down etc.

Post by **petefarrell360** » 09 Mar 2006 12:45 am

Indeed Steve, I see where you're coming from, it's just that it can get a bit tiring and once you've hit speed for motorway cruising the need for overtaking drops if well planned, and changing down wouldn't be too much of an issue occasionally, an overdrive option would be mega handy! It would certainly help my fuel consumption anyway!
Pete

Post by MJ » 09 Mar 2006 12:58 am

I guess the gearbox itself is a bit too close. Not sure what the ratios are on a 1.7, but (on the very few miles it's done on the motorway

) it feels comfy at 65, which is a pain. The 850 is still happy at 80

Post by **foggyjames** » 09 Mar 2006 01:02 am

You GLT guys want a 3.36 diff from a carb model...just that little bit lower....

The 'happiness' thing is related to where it makes power, at what throttle opening...and how that related to road speed via your diff. My car will very happily cruise at 100+ with relatively little power applied, but it's happiest in 'just tickling the throttle' conditions at almost bang-on 70.

cheers

James

Post by **petefarrell360** » 09 Mar 2006 01:06 am

Indeed, the GLT has no problems with how much power is applied, you're not foot to the floor, but the revs just seem a tad high at times, maybe the speed is a little high too......... but that's a different matter. It will sit at 70 all day though, that seems to be it's favourite spot, as you say just tickling the throttle.
Pete

Post by MJ » 09 Mar 2006 01:07 am

foggyjames wrote:but it's happiest in 'just tickling the throttle' conditions

Yeah, that sounds like what I meant