Peugeot 205 gti uprating query

[toby7]

Hi there

I've just registered with your site and would really appreciate your advice please regarding my options of improving my 1.9 xu9ja (d6b) code engine in my Peugeot 205 gti (series1 130hp engine.)

The 1.9 engine is completely standard at 116,000 miles now. Uses no oil and has the early Jetronic injection,

I new want to improve the power output. I realise the 8v wil not give huge power gains ( Most of the time I'm cruising at 110kmh open road to work ) but if I can optimise what peugeot have done already I'd be happy if i could get a real 150 bhp.
This d6b engine I believe is the 9.6 to 1 compression engine. What should compression presure in psi be for this engine if it is healthy?
Option 1/ Replace ecu with a fully programable engine management
This would get rid of the AFM and give me mapped fuel and ign. It would also give me more torque, nicer to drive especially with mapped ignition and more options to tune later. eg bigger throttle body etc

option 2/ Carbs - New Dellorto 40's , Weber 40's or Dellorto 45's ??

This I believe would give good power due to increased airflow but would economy would go right down ???THis I need to know. At the moment I get 320 miles per tank of fuel. Open road driving. what would carbs get if i drive quietly at smal throttle openings open road ( I mean if i had to drive quietly) and would you recommend going this route if tuned by a rolling road.

option 3/ If compression isn't within spec then I'll need to get something like the following done and stick with the std induction and jetronic system.

New rings, bearings, 3 angle seats, Head + Block /Liner skim .028 or whatever to get to 10 to 1 and reground cam.
.

Regards
Peter

[Guy Croft]

Hello Peter and thanks for posting.

The first thing I want to say is this: that mileage on an engine of nearly 2 liter capacity and fuel injected is nothing if the engine has had religious attention to the oil, coolant and fuel system, ie: been well maintained. I have stripped 2 liter Fiat TC engines of far higher mileage and found them to be excellent condition.
The second thing is that as far as any kind of tuning is concerned with the OE Jetronic system you should not aim for too much of a power increase because the injection system will not be able to cope with it. It will not compensate for increased air flow to any great extent - certainly not the level you'd see from GC style head work and cam change. The most you'd really get away with is a basic overhaul and valve seat job. Even then, if the valve seat job produced a gain in flow - which mine certainly would over standard - you might have to raise the fuel pressure on the injection rail.

This issue applies to all fuel injected engines.

So the unfortunate fact is that if you want it to fly, your cheapest option in the short term is to go sidedraft carbs, and yes, in the longer term you can say goodbye to fuel economy. Personally, reading between the lines, the induction noise will be intrusive compared to what you have now.

Some decisions there I think, over to you.

GC

[toby7]

Thanks Guy for your reply.
What I do will depend on the results of the compression test. If within limits then a new engine management will give me mappable ignition (more torque) and mappable fueling and get rid of the AFM.
Then any headwork, cams, compression etc may be tuned to suit.


Thankyou
Regards
Peter

[Christopher_205Rallye]

Hi Toby,

I will try to add something positive here. Don't all shoot me down:-)

AFAIK the cam on the 205 Gti is fairly wild for a production engine, and you need something quite wild to better it (the guys I know mostly use catcams). As guy said something on the subject, your car in its present state may not be giving you the manufacturers 130BHP figures due to teh mileage (and unknown oil changes). I know that many have rolled their 1,9's and only a handful have achieved this on respectable RR's.

To achieve the 150bhp you seek I would "imagine" that you will need both headwork (GC is preferred ) , wilder cam and throttle bodies and mappable ECU or weber 45's. to all of this you will bet increased induction noise possible reduction in low rpm tracability. Another option is to use the XU10 head which flows better then standard on the inlet side as standard. but there are some gasket issues (since it has a bigger bore). I can imagine that your fuel consumption will be worse. However I consistanly get good mileage out of my 1,3 rallye (on twin 40') as long as I drive nice.

As guy said it depends on your budget and how you want your car to drive afterwards.

One option you may not have considered is to just junk the 1,9 engine totally and fit the 16v Mi engine from the 405 or the Gti 6 engine. I think these both make somewher in the region of 160bhp as standard. You could also possible keep the standard induction system. (and mpg??) i know many people who have done this conversion and are more then satisfied.

It does fit...i can't find a better pic right now...

[toby7]

Thanks Christopher for your reply,

I think that because Peugeot did such a fantastic job in the first place (when the engine was in new condition)it is going to be hard to better the factory design and whatever i do it should be approached with accurate knowledge and as a total package.
Driving to work today i was trying to get a feel for how the engine pulled and where in the rev range it felt ok and where and what load it felt ok and not so ok. From my general impression the power/torque (whats there) curve isn't flat but has about 4 or 5 varying dips and bumps from 1500rpm to 5900rpm. Doesn't really want to go over 6000rpm. Sounds painfull. Either I'm being sympathetic else i'm chicken.

Mappable ignition at least is sounding more and more like a 'requirement'


Regards
Peter

[petert]

The key to making an 8V engine perform is squish height. Having the piston sitting 0.067" away from the head is less than desireable. You need to decrease this to approx. 0.030" either by block decking or a thinner head gasket. Plenty of tuners can get 150hp but few can crack 160hp with an OE manifold and TB.

[Guy Croft]

Hi Peter

very interesting Peter, yes 'Squish'. See also:

http://guy-croft.com/viewtopic.php?t=97

At an industry level very advanced modelling is used to design & evaluate the generation and effect of squish, super-sensitive because it can lead to power loss and a rough (I mean very rough) engine if it's done wrong. And it's not something I myself care to write about too much, probably a few industry experts already members, or will be who'll tell us more.

I know squish is a good thing up to a point and I do know some high rpm motors don't need much, that's all rather general, sorry. I tend not to do much to the bands unless they are shrouding the valves, figure the manufacturer probably go it about right. There are exceptions, the 2.3HS Vauxhall 16v has none to speak of and id not a high rpm motor - and I think did need some attention in that area (see below)

Peter -you don't by any chance have any back-to-back dyno results on that have you, please? I don't have any except tests on Vauxhall SOHC that were as identical as I could make them, one I think 6 bhp less than the other, I'm not ready to offer those details at this time because I cannot be certain as to the cause of the power difference between them, but may be cc related issue.

Thanks,

GC

[petert]

No sorry, nothing back to back, but I did get the shock of my life after getting 80kW at the wheels from a small valve head. I admit it was running avgas, but never in my wildest dreams did I expect that much. That was actually using a 0.5mm gasket, but I didn't want to recommend that for a street car. I had previously tried a 0.7mm gasket but hadn't dynoed it.

Taking that on board, the next engine was a Grp. A big valve version, flat top pistons, 11.5:1 and 0.020" squish and it did crack the 160hp barrier, again on avgas.

I do the same for my 16V engines as well. They sound a lot crisper and have a flatter torque curve.

[Guy Croft]

is it maybe just the higher CR?

Or am I reading that wrong?

GC

[toby7]

The engine I have is the XU9JA D6b (130hp model I 'm sure)
What is the factory setting for deck height ? ie distance from top of piston at tdc to top of block.
Also what is the thickness of the factory head gasket ?
I am taking this information on board (Thanks Petert in previous post a while ago)

Thanks
Peter

[petert]

is it maybe just the higher CR?

Or am I reading that wrong?

GC

I don't think so, as 8V engines which just have high CR, but with std. squish height ping badly if ignition curve is not altered. Also consider these two 1.9L 16V valve engines:

#1 - 10.4:1, std. squish height, 236 deg. @ 0.050" inlet cam, ported 36.4mm inlet valve head. Makes 100kW at the wheels

#2 - 10.8:1, reduced squish height, 226 deg. @ 0.050" inlet cam, std. head. Makes 101kW at the wheels.

The engines are otherwise identical in terms of manifolding, ECU, fuel etc.

Perhaps is a nature of the small rod/stoke ratio in these engines? The piston doesn't dwell at TDC very long.

[Dynodave]

All I would suggest toby is dont go the route of exhaust.. induction kits.. etc .because i have seen so many of these engines making std power on the rolling road after fitting all these mods.
I have even seen 3 so called 160bhp conversions from a so called pug 205 specialist which all made stock power.which is 122-124 on my rollers.
Ive also seen uprated cammed cars with modded heads make just over stock power............This engine is easier to get wrong than get right .So the only advice I would give is Change for a 16v i.t will be cheaper in the long run.
One last thing is this. check the ign advance on your dissy .
the springs go weak and the engines pink .people take to garage .garage backs off ign to stop pinking =peak power drops due to not enough ign.
this gets repeated again and again....I have seen nearly 20bhpgain from retensioning the springs in the dissy.So its worth checking !

[toby7]

I've just had the compression check( on my XU9ja 8v engine and leak down test done. Results not good. 110 to 120 psi across all cylinders. 100psi Leakdown test showed
only 40 to 60psi on the gauge and you could hear air coming out the oil filler.
What to do . . . what to do !
I'm having a problem finding an mi16 engine here in New Zealand.
Thinking outside the square here for a moment . ..what other engine would transplant without too much difficulty. Has anyone installed a Honda K20 else B16, B18 engine. Maybe even a Mitsubishi mivec or 4g63 engine ?. If this is not a good option then I've no choice but to rebuild my 8v.

thank you
Peter