205 1.9 Rallye Preparation

[unariciflocos 49 1 Cars]

Hi and greetings. I'm new to the forum and this is my first post.

 

I've bought a 205 Rallye 1.9 and I want to turn it into a track day car. This car has a bit of a history, the engine was rebuilt and then sat for 3 years, it started ok but overheated on first run, showed all the symptoms of a blown head gasket so I opened it up. Didn't see any obvious signs on the gasket so I'm thinking the thermostat was jammed closed.

 

Anyway I see this as an opportunity to rebuild the engine to the specs I want. I've bought 4 Mikuni carbs from a GSXR 1100 Suzuki and had a manifold made for them and I'm traying to follow the puma racing "recipe". I've oredered 43mm inlet valves and I'm going to port the head, I'm sticking with the standad cam and standard exhaust manifold for now, but I want to increase the compression ratio to 10:1. My aim is somewhere between 150 and 160 bhp.

 

I've searched the web and the forum but I can't figure it out. I have limited experience with engines so I was wondering if anyone could tell me how much I need to skim of the head to get 10:1 compression. Sorry if this has been discussed before and I didn't find it.

 

Thanks in advance.

[unariciflocos 49 1 Cars]

I'm having trouble finding the engine code and model of this particular car. It is one of the 1000 1.9 Rallyes made for Germany and there is little information about it. I can't even find anything about the engine in the owners manual that came with the car.

 

So my question is, since this 1.9 has only 105 bhp from factory compared to 128 of the standard 1.9 GTI, does it have the same CR or could it have a lower CR. I was told the difference in HP from the 1.9 Rallye to the 1.9 GTI came just from the fuel maps, but I'm starting to think that the CR could be different too.

 

We have 99 and 100 octane fuel available in Romania so I'm thinking I can run CR as high as 10.5 or 11, even if I'll use octane boosters or add just a bit of jet fuel .

 

Can anyone please help with my CR problem?

[jengis 0]

I believe it has the same engine as fitted to CTi's and Gentry models. Can anyone confirm this?

 

If so, "de-tuning" is from the following:

 

much lower compression ratio, not sure of exact fugure but there's info if you search. (around 8.5:1? ideal for turbo build!)

Smaller valves and a different cam too (possibly same head as early 1.6?)

Running a cat is the final restriction to the power output.

 

Its a common missconception that manufacturers just have a different map or ecu to achieve power dofferences. Sometimes it's right but not often.

[unariciflocos 49 1 Cars]

I did some research and indeed it is the XU9J1/Z (DFZ) that has a 8.4 CR, a cat and delivers 102 HP.

 

Running a turbo is far too complicated and I can't register a turbo charged or 4wd car in any rally in Romania as a beginner.

 

I have a spare head with brand new valves and cam shaft and I'm going to port it and fit it with 43 mm inlet valves.

 

I still need to figure out how much i need to skim off the head to increase the CR to 10 or 10.5 . I found CR calculators but i don't know the volume of the combustion chamber. If I can't figure it out mathematically I'm just going to take 1.5 mm off it and hope for the best.

[DamirGTI 342]

1.9 Rally version with low comp. engine was made for export , for German market (cos the 1.3 rally version did not meet German road regulations ..) , anyway as said it's the same type of engine as one fitted in 205 CTi (cabrio's) and UK Gentry's , it has DFZ code (1.9L XU9J1 DFZ)

 

So this DFZ engine had :

Low compression - compression ratio of 8.4:1

Smaller short valves - inlet valve 39.5mm , exhaust valve 33.0mm

Larger combustion chambers - sorry i dunno how much cc's (37cc me thinks but im not sure if that's correct ..)

Different low lift/duration camshaft - inlet valve lift 10.5 , exhaust valve lift 9.7

Different pistons - conrods are the same as on high CR engines (D6B) but the pistons are different , more precise the piston crowns with only 9cc (same type of pistons as the ones fitted in 1.6 engines ..)

Different calibration of the engine management with CAT added

 

However this engine has a very high compression height which reduces squish clearance and thus yields low down torque and throttle response.. (it's the bottom end which is very interesting for something -> read on ..)

 

 

Now , high compression D6B engine :

High compression - compression ratio of 9.6:1

Bigger longer valves - inlet valves 41.5mm , exhaust valves 34.7

Smaller combustion chambers - combustion chamber volume 34cc

Different high lift/duration camshaft - inlet valve lift 11.2 , exhaust valve lift 11.2

Different pistons - with deeper 15cc crowns

Different calibration of the engine management

 

The best thing what you can do with 1.9 DFZ engine is to whip the head off and stick the 1.9 D6B head on the DFZ bottom end ! i've done that , but with some other bits and bobs ... and now it has fascinating torque , power and throttle response trough all the rev range ... although , to make it work properly , it's essential to either re-curve the dizzy or to fit fully mappable ignition cos the compression ratio is rated at a bit high 11.1 with this bottom end/head combo , and it'll need at least 98RON fuel or higher octane rating if possible .. but worth to do by all means - it's cheap , easy to do conversion and effective (and reliable i didn't have any problems since i've made this engine .. of course if you tune it up properly afterwards it should last as the std. one )

 

Damir

Edited November 1, 2008 by DamirGTI

[andy0075 9 1 Cars]

Hi!

 

XU9J1 DFZ/DFY

 

LU2-Jetronic

1.905ccm

83x88mm

8,4:1

102HP at 6.ooo

142Nm at 3.ooo

 

I have often read that you can straight bolt a head from a DKZ engine ( 120 HP / 128 HP engine ) on

your DFZ block. Than you have a very high compression ratio.

 

Engines with this modification should go really, really good i have read in a german forum.

 

Andy

Edited November 1, 2008 by andy0075

[unariciflocos 49 1 Cars]

Thanks for the data.

 

The spare head I have is from a 1.6 GTI but i don't know the engine code (I'll check some pictures of the bottom end for the code), so it may be the same head if it is an early 1.6 GTI.

 

I'm going to be running bike carbs and custom exhaust with no cat so my only problem now is the head.

 

Should I try to modify one of my heads or should i look for a 1.9 head?

[welshpug 1,661]

as long as its a B6D head it'll be the same as the D6B 128hp 1.9 head.

 

Typically identified by the oil breather on the rocker cover, the earlier 105 bhp XU5 didn't have this, if the aluminium tag is still present check for the B6D code.

[unariciflocos 49 1 Cars]

ok, i've ordered a D6B head from a fellow enthusiast in Romania, it should be here in 3 days.

 

I have a few questions before i can carry on with the rebuild:

 

1. should i fit the 43mm valves or should i stick with the standard 41.6?

 

2. Most people that do head reconditioning here have no experience in performance porting, should i try and port it based on what i've read or should i leave it as it is and not risk ruining the head? (no flowbench available)

 

3. What is the optimal shape for the valves? tulip or flat?

 

4. what power output can i expect from: 4 mikuni gsxr 1100 carbs, BV ported head, 11.1:1 CR,std cam, std exhaust manifold, custom exhaust

 

Thanks all for your time and help