Xu10j2 Rfx Tuning

[Bam 0]

hi folks,

 

after a long time ago, i've sorted out my garage and i've found an 2.0L engine xu10j2 rfx from an 306 xsi.

 

the engine is running fine, but is very tired.

accerlation from idle to max rpm is very slow.

 

so, i've got some ideas and i need a little bit advise, maybe you have some experince about.

 

my ideas: (low budget)

 

- 205gti clutch + flywheel (= -1,7kg)

(i know,that the xu10 flywheel is lightener, but the clutch + plate are from 205 gti more then 1,7kg lightener!)

- alloy pulley (-1,2kg)

 

- ported cylinderhead

- was is the max cr for this engine good enough? 10,5 : 1? (stock pistions)

- polished valves

- cam: 296° 107° 12mm 3mm @ tdc (this cam was delivered with the engine) inlet open 41°, close 75°

 

- maybe mi16 gearbox

 

i'm unsure about the inletmanifold. wich should i use? gti one, with xsi tb? or stock inletmanifold?

 

- ive found a picture from an inletmanifold with 2 tb's!

looks very interessting (2x 60mm tb's) ....rrrrrrrrr....

 

thanks + cheers

mik )

[carbers205 1]

Hi mate, there isnt a lot that you can get out of this engine, especially on a low budget.

When I had mine I lightened the flywheel a bit, put in a crank from a 1.9 diesel (88mm) so the engine capacity went up to 2045cc, ported and polished the head and put in the cam from a 205gti 1.9 which is slightly lumpier than the 306 one. I also put on a beautiful stainless exhaust (make unknown)

The increase in torque was quite nice but it didnt feel like much had happened to the power, though I didnt take any before and after readings to compare.

Are you putting this engine into a 205? If so then you cant use the standard 306 plastic inlet as it will stop the bonnet from closing. I know one guy on here has put the rfx engine into a 205 and used the 205 inlet but the port shapes are quite different so will need matching up. The double tb inlet looks very strange, and using 4tbs will be expensive so Im not sure what the best way to go is.

I didnt have any problem as the engine was still in the 306 it belonged in!

So, dont expect too much from your work, dont spend lots of money and try do the work yourself, the engine should be a lot fresher once you have finished but not much more.

 

Andy

[Bam 0]

hi buddy,

 

hmmm.... thanks for your post!

 

but,that isn't that,what i've wanted to hear

 

but your idea to change the crank, sounds good...hm.

whats about the valve clearance? the head is 4/10 machined, in one week i get the head back (portet and with 7/10)

 

i know the guy who has ported an mountet the gti inlet manifold.

i've dropped out the cat., also i've here a 205 gti 4-2-1 supersprint exhaust manifold.

 

in ebay i have found 45 tb.... maybe i will get them -sounds like a bigger projekt

hm... injectors.....maybe 240-260cc

 

why the hell is the engine feels like an old grandfather?

whats the trick?

 

cheers

[carbers205 1]

I dont know what the trick is, several of the guys on here have agreed that the tuning potential on this engine is small, it does seem strange as the valves are slightly bigger on this head than the 205s and from the flow charts Ive seen the bare head does flow quite freely.

It could be interesting to change the tbs to single ones and get rid of the cat to see if they are what cause the restrictions.

As far as valve clearance goes, with a 205gti cam in and the 1.9 crank its was absolutely fine once I had skimmed 1mm off the top of the pistons. If you go for a higher lift cam though I cant guarantee it will clear the pistons.

[Bam 0]

thanks mate.

 

If you go for a higher lift cam though I cant guarantee it will clear the pistons.

 

runs fine!

 

in the next days,we will try th tbs.....

[carbers205 1]

How is this going now mate?

[Atari Boy 11]

I run an XU10J2 lump in my 205. I run it on standard 1.9 Gti management (the poorer of the two, I forget it's name).

I use a standard 1.6/1.9 inlet manifold with the inlet ports of the head ported and matched. I use a Piper cam (282 I think) also.

 

I had the head ported and polished before I fitted it to the car and I use a 1.6 BE1 gearbox and 1.6 flywheel.

 

I am really happy with conversion, I had it on a rolling road earlier in the year and it produced 142 bhp at the fly.

Edited August 31, 2010 by Atari Boy