Economical 205S - Lpg Vs Hdi

[Anthony 1,003]

205 DTurbo box is quite amusingly short I believe, 3k rpm in a 306 or 405 on the 1.9 DT engine is 80 mph give or take a few, that's just about peak boost+torque on a standard configuration, the 306 HDI box is a little longer which goes a little way to explaining the big difference in economy between the two engines other than simply the vast advancements in fuelling technology.

The two gearboxes suit the engines in question though.

 

A 306 HDi box would be terrible on a older TD engine in my opinion, as the much higher boost threshhold on a TD would make it all too easy to fall off boost and need to drop a cog on a typical A road. Indeed, I found that issue bad enough on the standard gearbox in my old 306 TD, let alone something with 20% odd longer gearing.

 

I'm also far from convinced that longer gearing gives significant economy improvements, as it's certainly not worked that way on petrol engined cars that I've swapped gearboxes around on.

[Russ_T 1]

I just want a 6 speed with my ratios + a tall 6th gear, but as that's unlikely/beyond my skill/budget just having a taller fifth for cruising would be ideal. I'm sat at about 3k when I'd prefer to be sat at 2k on a run

[welshpug 1,657]

it seems the hdi box works on a TD IF tuned, but I agree the standard TD box works very well with a standard engine.

[RossD 44]

205 DTurbo box is quite amusingly short I believe, 3k rpm in a 306 or 405 on the 1.9 DT engine is 80 mph give or take a few, that's just about peak boost+torque on a standard configuration, the 306 HDI box is a little longer which goes a little way to explaining the big difference in economy between the two engines other than simply the vast advancements in fuelling technology.

 

A longer gearbox doesnt equal more fuel economy, the opposite if anything. With longer ratios, the engine is simply going to be working harder for a given speed, possibly negating any fuel economy gains. Also weight doesnt make as much difference as you'd think, the biggest factor in fuel economy is aerodynamics.... (And a 205 aint that great in this area!)

 

The HDi is a far more efficient engine than the older XUDT lumps. Direct injection vs indirect injection, full ECU control over injection pressure, injection advance, quantity etc etc - I think Peugeot claimed 35% better economy out of the HDi. Certainly going from an XUDT 306 straight into an HDi powered 306 I saw a gain of about 10mpg, 45 vs 55mpg....

 

I could probably extol the virtues of the HDi engine all day, but at the end of the day its never going to set the world on fire, even with a nice remap. You will get a nice shove in the back from all the torque, but if out and out acceleration is what you are after, stay with a nice high revving petrol imo!

Edited May 3, 2012 by RossD

[Russ_T 1]

Weight does play some factor, I work 1200ft above my house, so dragging my little pug up the hill each morning I have lots less issues than heavy cars I appreciate I get to go down hill on the way home, but because my car is lighter it doesn't make it less effecient than a heavy one going down hill.

 

Ok the 205 isn't great, but it's not horrendous coed I don't imagine. It has a reasonably sloped screen, it's narrow, and it has a fairly small grill area. I am going to think about under engine trays and other things though when I've nothing better to do.

 

I think the biggest factor for me is tyres, since I went from 13" 165s to 15" 195s that cost me 5mpg. I'll aim for C5 steel wheels next I think and blow them up a bit hard.

 

I'm sold on the HDI though, like you say it won't set the world on fire but it should be a lot more fun than anything else returning those sorts of mpg.

 

I've posted on TDOCUK to see about which engine is multiplex or not etc http://www.tdocuk.com/viewtopic.php?f=41&t=12216

 

How much power are we talking before you should start thinking about slipper diffs? I've got one on my 300 but it's rwd but its only 300hp/300lbft in a car that weighs a lot more... hmm more to daydream about!

 

Cheers

[welshpug 1,657]

diffs are useful on standard engines

 

don't forget the larger van's (expert/dispatch/scudo) with 110 engines were not the same unit, they had the DW10ATED4, which in the cars was the 136 engine.

Edited May 4, 2012 by welshpug

[Russ_T 1]

I don't think my DTurbo really needs a limited slip diff though (I said slipper diffs, not just a diff)

 

Thanks for the heads up, will avoid engines from vans.

[welshpug 1,657]

That's what I was referring to as a "diff", and yes if driven hard even a 80 bhp XS will benefit from an LSD.

 

no need to avoid van engines.... but it would be a little more work, they do use the ML5/6 boxes.

Edited May 4, 2012 by welshpug

[Russ_T 1]

Really? I haven't driven a fwd car with one so I guess I wouldn't know, I'll add it to the shopping list then. I'm surprised as generally car manufacturers only bother at 200+bhp I thought.

 

I googled the DW10ATED4 and it appears to be a newer engine, a 16v equivalent used in 307s as well? I think the 136 was a DW12 engine...

 

http://www.peugeotlo...el/encode1d.htm

 

Thanks

Edited May 4, 2012 by Russ_T

[welshpug 1,657]

indeed there was a 16v in the 307, which did not get a dw12, oddly its called a 138 on servicebox, its the RHR engine.

[RossD 44]

For the first generations HDi's, the 16v was used in the vans and the people carriers (806\807) and the 8v engine used in the cars. 2.0 8v at 90bhp and 110bhp, 2.0 16v at 110bhp. 2.2 16v also available with 136bhp.

 

Second generation (2003-2004 ish onwards), the 2.0 is now 16v and is uprated to 136bhp. 2.2 has 170bhp with a twin-turbo setup. The 1.6 HDi replaces the 2.0 90bhp and 110bhp. Vans use similar engines, but with less power.

 

DW10TD is 90bhp first generation 8v 2.0.

DW10ATED is 110bhp first generation 8v 2.0.

DW10ATED4 is 110bhp first generation 16v 2.0.

DW10BTED4 is 136bhp second generation 16v 2.0.

DW10CTED is 153bhp third (current) generation 16v 2.0.

 

 

Anything before about 2001 should be non-mulitplex.

 

Easiest way to tell is to type the VIN number into Servicebox, this will confirm MUX \ non-MUX. Having a multiplexed ECU isnt the end of the world though.

 

Another thing to point out. The original HDi's came with both Bosch or Siemens ECU's. Even though the Siemens ECU is actually technically superior, Bosch is the one to use. Easy way to tell is the high pressure pump under the bonnet, and the lack of an in-tank pump on the Siemens.

 

Just out of interest, I put the figures for a remapped HDi into CarSim (A really old (DOS based) but seemingly very accurate car performance simulator). 130bhp and 235lb/ft gives 0-60 in about 7 seconds, 0-100 in about 19 seconds in a 850kg 205. Thats 1.9 GTi performance with 60mpg available when you aren't ragging it....

 

Also, I'd reccomend the BE4 box from a Xsara HDi 110, longest gearing of any BE4 I've found which should suit the lightweight 205.

Edited May 4, 2012 by RossD

[Russ_T 1]

7 seconds! Pah, no good, have to fit NOS as well

 

Thanks for that! I'll aim at that gearbox, can always change it if I'm not happy.

 

What extra would be involved from a mux setup? I imagined it meant a no-no to splicing it into my 205 dash etc (could be a naive view). If it's not the end of the world does that mean swapping to the older ecu/loom, or can the two be spliced but with more difficulty? Or are we talking aftermarket ecus? I only want to do it once, I'm starting to lust after the CTED!

 

Too much time on my hands + this forum = dangerous

[Strictly_Derv 34]

Just stick with XUD. I can easily get over 50mpg with my car, with the 1.8 box! I hated the box at first but now the engine's revvy(for a diesel) after the Gov-mod it's really good as theirs no power loss changing gear as it's so short. But i'm about to be fitting a K04 so it will definatly need that short box. Even as it is now it's faster than my sisters 306 GTI-6, so it's far from slow.

Another advantage I find with the short box is that you can change gear at 1500rpm so it great when pootling about, where as a HDI will need 2000rpm to change.