Peugeot 205 Si

They are usually custom. I take the sample to B&R Brakes and hand over about $160 for the pair. Make sure they add the rubber bush for the strut mount. They need to be road legal.
 
@PeterT I've be been thinking about what you said about gear and FD ratios, and (apart from the ridiculously short 1st, which probably doesn't really matter too much), your suggestion of a 4.43 cwp plus 3-4 and 5 out of a GTi/late XSi/GTi6 looks just about perfect for getting the most out of an Si!

Obviously, you knew that already, but the difference really becomes pretty stark when you put it in a picture: https//205.si/gearbox

I assume that, when building a gearbox for a racing car:
  • first, work out the implied top speed is, based on the power of the engine and the shape of the car (no point having ratios that suggest 250km/h top speed if physics says "No")
  • next, pick a top gear and final drive combination that implies top speed at redline (don't need to be sitting at 1500 rpm on the freeway)
  • next, find a longish first gear, to get from 0 to some kind of speed (and reducing the range to be covered by 2-4)
  • next, find an evenly spaced combination of 2-3-4 to fill out the gap between 1 and 5
And I assume it is similar for a rally car, but maybe with a bit less emphasis on top speed (so everything a bit shorter)?
 
natumbri said:
  • first, work out the implied top speed is, based on the power of the engine and the shape of the car (no point having ratios that suggest 250km/h top speed if physics says "No")
  • next, pick a top gear and final drive combination that implies top speed at redline (don't need to be sitting at 1500 rpm on the freeway)
  • next, find a longish first gear, to get from 0 to some kind of speed (and reducing the range to be covered by 2-4)
  • next, find an evenly spaced combination of 2-3-4 to fill out the gap between 1 and 5
Click to expand...
Basically, that's it! Thus for circuit racing, you need to just hit the rev limiter in 5th at the end of the main straight. The problem with BE1/BE3, is that all 2nd gears are the same. The next problem is that 3-4 are joined as a pair. So there's really only a few combinations of 3-4 that you can use and the GTi6 combo is excellent, as it's nice and close. There are only three common 1st gears - 3.45, 3.25 and 2.92. The later is obviously what you want and they come from Mi16's or 1.9L GTi. The most common is 3.25 and it's not the end of the world as you're rarely in 1st anyway. The 3.45 is just a pita.
 
Hi everyone (@PeterT), given there are a few things that I'm doing to the front end, is there any reason not to
  • build up a new front subframe with everything I want on it, cleaned and/or refreshed (including, eg, brakes and struts)
  • drop the existing subframe out
  • put the refreshed one it
It seems better to try to not do this stuff under the car, given I have a subframe and am replacing/refreshing lots of the bits...?

If I disconnect the brake and pas hoses, unclip the clutch cable, disconnect gear linkages, disconnect the steering column, unbolt the struts, unbolt the subframe, unbolt the bottom engine mount, can I then pull the whole lot out?
 
Yes, you can do it, but you also need to either disconnect the suspension arm and control arm at the subframe or the suspension arm at the wheel hub carrier. I would suggest you disconnect the suspension arm at the hub carrier, it's just a ball joint and you might want to replace that with everything else.

Just before you start the whole thing I would also suggest you check the spare subframe is in good nick otherwise you might find it's not by having weird issues with the steering geometry. Get the tape out and measure some stuff and compare with the one on the car.

After the swap you might need a steering alignment anyway because of the tolerances of all the bushes you will replace but if the spare subframe is not in good nick (distorted, bent, etc) this alignment may not be enough to bring the car back to proper working order and it will be difficult to chase what's wrong. Cheap insurance to check now rather than later.

Also, be careful how you press the suspension bushings out. The arms are pressed steel and easy to distort and the bushings are a very tight fit and give you bugger all to push against.
 
natumbri said:
Hi everyone (@PeterT), given there are a few things that I'm doing to the front end, is there any reason not to
  • build up a new front subframe with everything I want on it, cleaned and/or refreshed (including, eg, brakes and struts)
  • drop the existing subframe out
  • put the refreshed one it
It seems better to try to not do this stuff under the car, given I have a subframe and am replacing/refreshing lots of the bits...?

If I disconnect the brake and pas hoses, unclip the clutch cable, disconnect gear linkages, disconnect the steering column, unbolt the struts, unbolt the subframe, unbolt the bottom engine mount, can I then pull the whole lot out?
Click to expand...
Yes, it's definitely more manageable to drop the subframe out. Separate and leave the struts hanging if you like, then take them out after. Leave the rack on the subframe and separate at the pinion. When it's out on the ground, you can swap the power steering rack over.
 
While I'm accumulating bits and pieces for the car, I spent some time making a very simplified mathematical model of a Peugeot 205: https://205.si/simulator

The RPM v Nm curves I'm using are just guesstimates I found on the internet. Has anyone got a real life actual dyno of a motor (or wheels), together with relevant car stats (mainly gears, FD, weight, tyres, 0-100, and top speed) so I can check (and tune) the model?

Looking at what it spits out using the internet torque curve, it doesn't seem like it is wildly off...?
 
Is there any difference between the subframe in a 205Si manual vs an automatic?
 
At the risk of getting flamed… can anyone tell me what/where these things should be connected to please? (On a 93 Si)
 

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First is the Diagnostic Connector (TEP/ PP2000), second is a test connector for the coil from memtory.
 
You can plug a TAD100 controller into the connector and adjust the ignition timing, plus check the fault codes.
 
Jared said:
At the risk of getting flamed… can anyone tell me what/where these things should be connected to please? (On a 93 Si)
Click to expand...
No idea where the green connector goes, that is the ECU loom, you may have o investigate under the dash, but before you do that, peel back the insulation a bit and see if you can find some numbers on the wires. That will help you if you have a wiring diagram.

The coil wire is easily identified if you take the connector off the coil and check where it goes in the coil. Look then at the coil specs, it will tell you where the wire needs to go. I would hazard a guess it may be your tach wire. Does the tacho work?
 
schlitzaugen said:
No idea where the green connector goes, that is the ECU loom, you may have o investigate under the dash, but before you do that, peel back the insulation a bit and see if you can find some numbers on the wires. That will help you if you have a wiring diagram.

The coil wire is easily identified if you take the connector off the coil and check where it goes in the coil. Look then at the coil specs, it will tell you where the wire needs to go. I would hazard a guess it may be your tach wire. Does the tacho work?
Click to expand...
Green connector question answered twice already!
 
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