Merkur XR4Ti ??
 

Hi everyone. I'm new here and I'm in southern Ontario Canada. Lately I've had the urge to build my own roadster. I got pretty excited when I learned that a North American Merkur xr4ti could possibly be used for the build (I think) My son has one that we're pulling the 2.3 turbo motor out of for his project, but he doesn't need the rest of the car. We also have an extra engine (unknow condition internally).
So what I have kicking around is this,
-basically entire xr4ti (alloy wheels, T9, Koni suspension, etc)
-MG Midget seats
-autometer speedometer
-gauges
-enough tools
After I do a little more research, it looks like I may take the next step and order the book. Is the Haynes manual the one that would fit my build the best??
Thank you very much, and
MERRY CHRISTMAS.
Jeff:D

Welcome to the forum! By all means use it as a donor. And do get the Chris Gibbs book. Essentially, you'll use the front hubs, transmission, diff, driveshafts, rear hubs, steering shaft from the Merkur. They're getting rare in Europe too, so having one at your disposal across the pond is a chance that's too good to miss!

Thanks Albert. I looked at your build. Nice job:cool: . Sure wish I could read it.
Jeff

Hi Jeff, my name is Bill, and I live in Calgary. I am getting the parts together to hopefully start building in the New year. My base will also be the XR4Ti.

cheers,

Bill.

Hi Bill, Noticed in another post that you are pretty familiar with xr's. Do you have an opinion about the durability of the T9 and the xr's open rear end? I'm kind of considering maybe just biting the bullet and going with a T5 before I build an entire car around a T9. I also have a GM 10 bolt posi rear in the garage I could use (currently 2.73:( ). Thanks and Merry Christmas
Jeff

Do have a good hard look at the gear ratios in the gearbox's.
The T9 box has better ratios than the MT75, the T9 from the euro V6 engine cars a bit better than the 4 cylinder cars but I don't know what the Merkura ratios are. The T5 which Europe knows as the one fitted to the Cosworth Sierra has the best ratios available and is the strongest of the gearboxes, I believe it was fitted to the Mustang over there.
It's all about first gear, MT75, 3.9. T9, 3.6. V6 T9, 3.3. T5, 2.9
Then look at tyre/wheel sizes and the Differental ratios, in the Euro Sierra we have 4 available ratios although there are more available
3.9, 3.6, 3.3, 3.14, in 7" & 7 1/2" crown wheel, push in or bolt on shafts and some with Limited slip (locker)
As a general rule the 3.9 & 3.6 are best for Haynes with car engines and the 3.3 & 3.1 better for bike engines

google translate works quite well on alga's build diary

http://translate.google.co.uk/transl...f%3D2%26t%3D14

Type 9 will be fine in most applications, it has less weight to get moving than in a sierra so the strain on the box is significantly less.

Basicaly you should be able to use the same components as any other sierra ( except 4x4 models ).

Your MG seats are probably no use though.

TT

Hmm, I think the strain on the gearbox depends on the power (torque * rotational speed) being transfered though it, not the weight being moved or anything else. The torque, though, is limited by the grip of the rear tyres, which is directly proportional to the weight on the rear axle. I wonder, what is the practical limit of torque/power that can be put down on the Roadster with semislick tyres like R888?

It has been discussed several times on here that 160-180 bhp is the limit for a Seven type car beyond where there are diminishing returns from extra power. Perhaps that is the limit of typical road tyres with the roadster's weight?

The Sierra's standard diffs are said to last forever and deal with a lot of power withouth any problems. The only reason to use a different diff is if you want an LSD.

Put the same driveline in a car weighing 45 tones. Will the gearbox survive less well than in a car at .45 tones.

The torque required to accelerate the heavier load is much higher.

TT

Nah, realistically the engine will stall with 45 tonnes. It will not be able to put out enough torque to move the weight. The strain on the gearbox will be limited by the power of the engine if we disregard the impacts on stalling.

I'd put it the other way around: the same torque will accelerate the smaller weight quicker. It's plausible that the load cycles on the transmission will be cumulatively shorter on a Roadster, but then again Sierra was most probably someone's docile daily driver, while the Roadster is a throwabout toy if not a race weapon.

Consider a Sierra and a Roaster on a rolling road dyno -- the strain on the gearbox depends solely on the power of the engine that's getting put down through the wheels.

Wow, Thanks all. Lot's to think about.
"my" T9
1st- 3.36:1
2nd- 1.81:1
3rd- 1.26:1
4th- 1.00:1
5th- 0.82:1
.
Axle ratio- 3.61:1
Final drive- 2.98:1
205/60-15 tires (about 24" tall)

You have the V6 T9 Ford rate this at 155bhp and 155 ft/lbs torque but we know by experience that it will be ok at 180 on the road.
Slicks can kill a gearbox that's not up to the job.
However build the car with what you have to hand you can always upgrade later

I agree with snapper, you can always upgrade later.
My Xr has the T5 from a Mustang (not the best of ratios, but lots available in the scrap yards.) You can also upgrade it to the Cosworth ratios and higher torque specs. (available off E-bay, for approx $450:00US if I remember correctly, I have that info if required.) I Just had to aquire the Turbo Coupe bell housing to mate it to the 2.3L block.
Because I have 2 spare T5 boxes, one will be installed in the kit car.
MC2 racing also does a conversion to convert the Stock XR diff to a Chev LSD type diff for approx $500:00US. (The internals fit into the Xr diff casing.)
The Toyota Supra LSD diff could also be an option. This diff can be made to work in the Xr, so it should be possible to make it fit the Kit car. This diff has a few ratio options I believe.

cheers,

Bill.

I have been working on a Roadster with the Merkur donor. In the US, the 2.3 liter engine was rated at 175 hp (130 kW) and 264.0 nm / 194.7 ft lbs, so I think the T9 could handle most powerplants.

To those using the Merkur diff, be aware that the housing is wider than the Euro spec. SB4 and CP10 will need to be moved accordingly.

Mark Bates

Seems we have some pretty intelligent people here:cool:

Bill, My son has an almost new aftermarket rebuildable Eaton plate type lsd that uses 26 spline GM axles (was in Chevy Monza) but it's a 2 series carrier. Any idea if it could be used with a spacer on the xr's ring gear? I believe the Eaton into XR swap claims to need a 3 series carrier?? I'll do some searching over at Merkursport. Thanks

Jeff

Jeff, the best option would be to fire off an email to Chris at MC2 Racing. He could tell you exactly what they do.
There is a fair bit of info at the MC2 site as well. Also do a search at the Merkur Forum.
Not sure about what you ask, as I installed a 7.5`Cossie Diff into my XR. Basically a straight swap with some spacers etc. I have 2 stock Xr diffs lying around that I was considering using. I was also thinking about the Supra Diff into the XR and the Cossie Diff into the Kit car.
I will be looking at Diffs later, as I begin the build in the new year.
cheers,
Bill.