Club 80-90 Forums

I am running a 1Y engine mated to a 1.9 petrol 4 speed box and it sounds like it's revving it's nuts off at 55mph
I'm guessing a different box would be cheaper that having mine removed and fiddled with?
Any constructive advice would be great, I have read the wiki and to be honest the list of boxes and ratios baffles me so advice from someone running the same engine would be great

There is an age old issue of torque (twisting effort) versas speed (how fast the driveshafts turn)

Increase the speed for a given RPM and you reduce the torque (the ability of the engine to continue to push you along)
What this means in practice is you may lower the revs slightly but as a consequence find that you are having to change down a gear at the slightest headwind or incline.
Of course you read on here of the users who have increase their final drive ratio by using a taller gear ratio but what they don't tell you is that they have fitted 130bhp TDI units or Subaru engines with 50% more output than a standard 1.9 wasserboxer.

If it really bothers you then play with tyre sizes and go for a 3 - 8% increase in circumference by fitting something like 205R14C on the rears (just over 5% larger circumference) obviously dependent upon the rims you currently have fitted.
Or Mercedes 15 inch steel rims....use an online tyre size calculator to compare the different overall circumferences to a standard 185R14C.


Martin

Agree with Martin. Gearboxes and ratios not worth chasing. That route will just eat money and no guarantee you'll be happy at the end of it whereas a change in rolling circumference can make a lot of difference and cost much less.

I posed the same question some years back and a wheel change solved it for me.

Do you know what code your 4-speed is? There isn't a massive difference in top gear across all of the stock petrol boxes listed here, 4 or 5 speed:-

http://rjes.com/html/gearbox_types.html" onclick="window.open(this.href);return false;

So you won't gain much by swapping for another stock box if you are already running a petrol box.

I really noticed the difference between the 8L that was in mine and the 3H that replaced it.

And didn't I tell you NOT to put treacle in that 8L? Oh no, you wouldn't listen. All that guff about 'sweetening' the gear change....

The van has already got 215/70/15's fitted to merc rims when I got it

Yup...4.6% larger diameter....but that's it mate, go substantially bigger and you may find it has a negative effect ie: inability to hold cruise speed on the flat without having to hold to almost full throttle.

Martin

op contated me, without knowing what code box (and ideally what revs we are really talking about) he has I can't give him any meaningful advice and one mans revvving it's breasticles off is anothers in the sweet spot - just because the van was originally a 1.9 petrol does not mean it still has a DU or DT gearbox in it, if it had a DT it would be sweet with the 1Y
there are best part of 100 different T25 gearboxes, for a reason, to suit the myriad of different engines and vehicle types and uses

Cheers Aidan for taking the time to reply on a Sunday
I will climb under the van tomorrow and report back

I think a lot of diesel conversions sound like they are "revving their nuts off" due to inlet tract noise. If you can reduce the noise, the engine can be just "buzzing along" at the same revs, and you won't notice it.

Is the air filter a proper paper filter inside a proper box? and is the box connected via a properly airtight tube to the snorkel tube inside the left hand vent duct? I suspect if this is not the case the the inlet noise will be very intrusive. I put in a lot of effort to reduce this noise when I did my conversion, and it is quite happy cruising at 3600-3800RPM, with similar gearing to a petrol gearbox. As soon as I remove the crinkly plastic tube between the filter box and the snorkel tube it gets very angry sounding.

colinthefox wrote:I think a lot of diesel conversions sound like they are "revving their nuts off" due to inlet tract noise. If you can reduce the noise, the engine can be just "buzzing along" at the same revs, and you won't notice it.

Is the air filter a proper paper filter inside a proper box? and is the box connected via a properly airtight tube to the snorkel tube inside the left hand vent duct? I suspect if this is not the case the the inlet noise will be very intrusive. I put in a lot of effort to reduce this noise when I did my conversion, and it is quite happy cruising at 3600-3800RPM, with similar gearing to a petrol gearbox. As soon as I remove the crinkly plastic tube between the filter box and the snorkel tube it gets very angry sounding.

I only became aware recently (from a conversation on another thread) that a 2wd diesel was supposed to have a snorkel in the inlet tract. My 1.6d, and later 1Y conversion which used the same airfilter and plastic box, just had an air intake in the bottom of the plastic box - it was never attached to anything. Both engines were stupidly noisy above 55. My tdi is also noisy, but that has a cone filter under the duct and no snorkel. It shakes the van between 65 and 70, then quietens down!

Ok, it's a DY code on the box running 215-70-15...... Can't for the life of me get a reliable rpm calculator to show me what's what

Chiefy wrote:Ok, it's a DY code on the box running 215-70-15...... Can't for the life of me get a reliable rpm calculator to show me what's what

Well according to the chart I posted further up the page, a dy is one of the lower geared diesel boxes, so there are certainly other options to bring the revs down (I'll let aidan recommend a more suitable option)