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A couple or three questions....


Bigj66
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I noticed there doesn’t seem to be any stainless exhaust systems for the 2.25 with four branch manifolds included. Is that because the cast unit flows well enough and isn’t really necessary or because you would also need to change the inlet manifold?

Does anyone have any feedback on the use of an Ashcroft high ratio transfer box with the 2.25 petrol? Does the engine need to be more powerful than standard to pull the higher gearing?

What power steering pump and pulley arrangement is used for fitting power steering to a 2.25 petrol? Can a 2.5 petrol 90 setup be transferred to the 2.25?

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ACR in Glasgow do all sorts of tuning for the 2.25, including the manifolds you’re after (and 2.8 stroking, performance heads, cams and a whole lot of tempting but expensive smile inducers).

The HRTC gives a 32% step up, compared to an overdrive’s 28%.  3.54 diffs give about 35%.  The big difference practically is that the diff swap screws up the speedo, so that needs recalibration, and also affects low range, while the HRTC and overdrive leave the speedo as accurate as it ever was (mine was set very well by JDO1.com).  The HRTC leaves low range useful, and of course overdrive is selectable and so entirely flexible.

Personally, I think that HRTC is not a good idea behind a standard 2.25 or a 12J engine as it makes acceleration poor, especially from stationary.  I’m pretty sure Ashcroft used to have a similar comment saying it wasn’t recommended for the standard 2.25, but that is certainly not on their product description anymore. It’s going to be very subjective, depending on how you use the vehicle, the local topography and what sort of performance you want, but having tried driving that engine and pulling away and accelerating with and overdrive engaged, I wouldn’t want to do it with the HRTC.  I think it’s still a much better option than the diffs, though, and it is at least stronger, quieter and more efficient than the overdrive option (no extra gear sets or bearings to sap energy).

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36 minutes ago, Snagger said:

ACR in Glasgow do all sorts of tuning for the 2.25, including the manifolds you’re after (and 2.8 stroking, performance heads, cams and a whole lot of tempting but expensive smile inducers).

The HRTC gives a 32% step up, compared to an overdrive’s 28%.  3.54 diffs give about 35%.  The big difference practically is that the diff swap screws up the speedo, so that needs recalibration, and also affects low range, while the HRTC and overdrive leave the speedo as accurate as it ever was (mine was set very well by JDO1.com).  The HRTC leaves low range useful, and of course overdrive is selectable and so entirely flexible.

Personally, I think that HRTC is not a good idea behind a standard 2.25 or a 12J engine as it makes acceleration poor, especially from stationary.  I’m pretty sure Ashcroft used to have a similar comment saying it wasn’t recommended for the standard 2.25, but that is certainly not on their product description anymore. It’s going to be very subjective, depending on how you use the vehicle, the local topography and what sort of performance you want, but having tried driving that engine and pulling away and accelerating with and overdrive engaged, I wouldn’t want to do it with the HRTC.  I think it’s still a much better option than the diffs, though, and it is at least stronger, quieter and more efficient than the overdrive option (no extra gear sets or bearings to sap energy).

Cheers for the great feedback.

With a more powerful (100bhp) 2.25 engine do you think the TB would be better suited or is it still best left to the V8 and TDi conversions?

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I’m not that familiar with the torque curves of the petrols, having converted mine to diesel a long time ago, but as long as you have a reasonable amount of low down torque for pulling away, it should be OK.  It’d still be horrible for towing, town driving or if you live in a hilly area, but if you drive a lot of dual carriageways, it may be very good.  It has its pros over overdrives, so is definitely worth consideration.  But it’s main win over the overdrive is price.  If you can afford a good overdrive, I’d always recommend that, despite its few drawbacks, because of how you can engage or disengage it at will.

It depends on the torque (not bhp) that your engine can deliver in the 800-2000 rpm range and your specific driving needs and conditions.  I suspect you’d be on the cusp of it being ok if you’re not towing with a 100bhp engine - it’s torque must have been increased a bit.  But that is a subjective opinion too, based on a level of acceleration that I consider I need (definitely not a racer!).

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Yep, they’re not far from me.

I’ve noticed the difference with the HRTB that I have on the 110 and which usually means choosing one gear lower than you would normally select especially off turbo when driving around town or up hills. Sounds like it would be similar with the S3.

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With a 110, going from 1.4:1 to 1.22:1 is about a 15% rise (1.4/1.22).  The Series HRTC is a 32% change, so same principle but very different result.  It’ll need a strong engine and probably a bit more clutch slipping than the 110 case.  I can’t remember the SIII gear ratios, but if there is a 30% or so difference between first and second, then it’d be worth test driving pulling away in second gear and never using first- it’d give an approximation of what to expect with first with HRTC.

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Unless you're trying to keep it original or struggling for space, you're better off fitting a modern 5-speed and LT230 if you want to raise the gearing - cheaper, stronger, more gears, better range of ratios & easy spares available.

And no, permanent 4WD doesn't make a big difference and you don't have to change to CV's. You can make the LT230 RWD if you want though, either by kit or by DIY modification.

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12 hours ago, Snagger said:

I’m not that familiar with the torque curves of the petrols, having converted mine to diesel a long time ago, but as long as you have a reasonable amount of low down torque for pulling away, it should be OK.  It’d still be horrible for towing, town driving or if you live in a hilly area, but if you drive a lot of dual carriageways, it may be very good.  It has its pros over overdrives, so is definitely worth consideration.  But it’s main win over the overdrive is price.  If you can afford a good overdrive, I’d always recommend that, despite its few drawbacks, because of how you can engage or disengage it at will.

It depends on the torque (not bhp) that your engine can deliver in the 800-2000 rpm range and your specific driving needs and conditions.  I suspect you’d be on the cusp of it being ok if you’re not towing with a 100bhp engine - it’s torque must have been increased a bit.  But that is a subjective opinion too, based on a level of acceleration that I consider I need (definitely not a racer!).

Yes I second all of this having recently completed a 2a rebuild Inc a 200tdi, HRTC and 3.54 diffs which I think it was snagged or fridge that warned me against but having already fitted all this before I was warned I wanted to try it and I half like it and half don't meaning as what's been said it's to hi geared for town work but usable if u use first gear and way over geared for motorway work meaning it runs out of puff before it runs out of gearing, if I'm honest it's more suited for flat country work , no good for towing and would probably need to use low box for hill starts, I did for a short spell try one of my old 4.71 diffs which was better for towing and town work but was absolutely useless on a motorway meaning it ran out of gearing before it ran out of puff but as I'm doing the Billing trip in June and a couple of motorway trips before hand I've decided to refit the 3.54 diff but plan to obtain another gearbox with a std tranny box may try it with the 3.54 diff first and see how it is and sell the HRTC and the other gearbox as one unit :(

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1 hour ago, Anderzander said:

And apparently they are shipping with carp bearings 

Well if Britpart have taken over it's a crapshoot innit :( shame as RM made some really quality stuff, I assume Britpart made them an offer they couldn't refuse.

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Thanks for the responses so far. Any thoughts on the power steering pump arrangement?

Could I use one off a 2.5 ninety, petrol or diesel or even a TDi given the similarities of the blocks to the 2.25?

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Of course you can. Start by looking at the parts book for the 90/110.

There were different timing chests used, one for air con and ones without. 

Finding all the right parts could be fun.....

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On 3/9/2020 at 5:51 AM, Snagger said:

ACR in Glasgow do all sorts of tuning for the 2.25, including the manifolds you’re after (and 2.8 stroking, performance heads, cams and a whole lot of tempting but expensive smile inducers).

The HRTC gives a 32% step up, compared to an overdrive’s 28%.  3.54 diffs give about 35%.  The big difference practically is that the diff swap screws up the speedo, so that needs recalibration, and also affects low range, while the HRTC and overdrive leave the speedo as accurate as it ever was (mine was set very well by JDO1.com).  The HRTC leaves low range useful, and of course overdrive is selectable and so entirely flexible.

...

Not that I am any expert but thought it was worth mentioning a GPS digital speedo about £50 (52mm dia). No setting up required (apart from wiring in) and I have found it accurate. Insurance company quite happy and in favour. In my case I found the PO had sheared a speedo cable screw which means to rectify taking out gearbox and attempting to drill out and retap the hole which is a lot of work. a job I am unlikely to get round to for a long while as the LR is my only motor on the road. I'm pleased with it and will do the same on my kitcar. If you'd like a wiring diagram PM me.

IMG_20200303_155834.jpg

Edited by jessejazza
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I have a Roamerdrive (mine is old enough to have Roverdrive on the tag, and I was told by Martin, the UK sales point at the time, that it was the first in the UK).  It’s a very good piece of kit.  The mesh of the output gear is a little bit noisier than a standard transfer box input gear, but nowhere near as noisy as a Fairey.  The original bearings were disappointing, the big front bearing was slightly off with a squeak at one point when dry, and all unmarked, so evidently Chinese rubbish.  I replaced them after a huge oil leak from my transfer case let the unit run too dry and failed the sun shaft bearings.  Spectacular bearing condition, but it was running and was rebuilt with only new bearings and a sleeve on the sun shaft’s bearing surface.  Been fine for years since.  That is testament to the robustness of the design.  I got mine in 2007 or 2008 for about £800.  Amazing how dear they are now.  Fairey tend to be around the £3-400 mark complete, with a few companies like Syncro Gearboxes selling kits to rebuild them.  Weaker though it is, I’d still take that path over HRTC.

They have picked up a few negative comments about their reliability, and Mark Saville has claimed three rebuilds in 15,000 miles.  That doesn’t fit my experience at all.  It’s quite possible his problems were down to other faults with his vehicle, incorrect fitting, running it dry or some other operator error.

In response to Cornish’s post, yes I was me who advised against the diff and HRTC combination.  I ran a while with the 3.54s and the overdrive.  The overdrive was happy, but using it in third gear with the tall diffs broke the main shaft gear wheel (stripped a few teeth off).. Ed had exactly the same failure with using 3.54s and overdrive behind his Tdi too, and I’m sure there was a third, possibly a member on here who had it. So, the HRTC and diff combination would eventually do the same.  But I agree, overdrive/HRTC with 4.71s is still a bit low for dual carriageway use with a V8 or Tdi.  I plan 4.1 diffs with an impose rule of never using the overdrive in high range except in 4th (ie a fifth gear).  John (Fridge) is quiet right that an LT77/LT230 fit is more practical, durable, quiet and maybe even less leaky.  I’m only persisting with the original because I already have the overdrive and can’t sacrifice any more VIN points without having an IVA check and losing the tax exemption.  

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On 3/9/2020 at 1:24 PM, FridgeFreezer said:

Unless you're trying to keep it original or struggling for space, you're better off fitting a modern 5-speed and LT230 if you want to raise the gearing - cheaper, stronger, more gears, better range of ratios & easy spares available.

And no, permanent 4WD doesn't make a big difference and you don't have to change to CV's. You can make the LT230 RWD if you want though, either by kit or by DIY modification.

John can you just expand on this please? Are you referring to the fitting of the Series transfer box to the LT77 or the modification to the existing centre diff that allows selectable 2/4WD? If the latter then does the LT77 transfer lever still shift between high and low ratio but instead of locking the diff it just selects 2/4WD instead?

If the centre diff mod does this then why would you choose to do the series transfer box mod instead as it seems like more work and expense to arrive at the same result?

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