xr2 engines

roofer · 31-05-2005, 03:52 PM

Ive just bought a 2003 xr2 engine, if i want to race it in 2 litre can i do any mods to it ? im thinking of fitting the front half of my 260 offshore motor and converting it to efi so i can run my mad efi and mad intake on it and getting power up to around 260hp.
Ive been offered a new 280 drop on and nearly new 280 full motor, if anybodys interested in them pm me for details.

Burty · 31-05-2005, 06:54 PM

Is it short shaft?

roofer · 31-05-2005, 06:57 PM

yes

JamesM · 31-05-2005, 07:13 PM

The XR2 front crank case half will only accept a 5 petal reed manifold and I believe your mad efi is a 7 petal setup. In fact I think other than laser EFI all the EFI front ends, horn, SVS, Smilin Jacks etc. are 7 petal. I'm pretty sure if you want to run EFI on an XR2 you need a 2.5 front case half.

Burty · 31-05-2005, 07:17 PM

Quote:

Originally posted by roofer
yes

might be interested midsection and box for the right money.
PM me a price if you dont want to post it. maybe a swap with cash with mine?

roofer · 31-05-2005, 07:37 PM

johnny i know ive got to swap front halves off my 2.5 to make efi work,it says so in my post

burty the xr2 comes with sportsmaster box running a 2 to 1 gearset and i dont want to part with it.

I may run the xr2 standard yet so if anyone's interested in mad efi total control ecu and mad efi intake pm me.

roofer · 31-05-2005, 07:39 PM

by the way can i do any mods to engine if i want to race in f200?

Taz · 31-05-2005, 08:46 PM

I may run the xr2 standard yet so if anyone's interested in mad efi total control ecu and mad efi intake pm me. [/B][/QUOTE]

Ah mate if only i wasnt skint

JamesM · 31-05-2005, 10:18 PM

Quote:

Originally posted by roofer
johnny i know ive got to swap front halves off my 2.5 to make efi work,it says so in my post

Oh yeah so it does

JamesM · 31-05-2005, 10:25 PM

Quote:

Originally posted by roofer
Ive just bought a 2003 xr2 engine, if i want to race it in 2 litre can i do any mods to it ? im thinking of fitting the front half of my 260 offshore motor and converting it to efi so i can run my mad efi and mad intake on it and getting power up to around 260hp.

Dude I would think that for a 2 litre to make that sort of power it would have to rev into the 8's in which case you would need the big rods from your 2.5 too. The XR2 has small rods as standard. People talk about 2.5's having either big or small rods but they're both big when comapared to the XR2's rods.

So to conclude:

2.0 small-small rods
2.5 big-small rods or big-big rods

roofer · 31-05-2005, 10:43 PM

I bought the xr2 cos they're meant to be more reliable than the offshore engines I was tempted by a nearly new 280 efi ,but at 9k for an engine that will go bang i decided against it.I dont know wether to repair my old engine, part it out or convert into a 2 litre xr2 and use as spare engine.

johnny the mad intake makes around 30hp and the mad efi ecu about the same, the ecu also gives another 400 rpm's so maybe 260 is achievable.

JamesM · 31-05-2005, 11:45 PM

I'm sure it would be achievable but at higher RPM, so you may need to use the chunky rods from your 2.5. Have you seen XR2 rods they're very thin.

Also that extra 30hp may only apply for a 2.5 and be a bit less for the 2.0.

XR2's are more reliable than the 2.5 OS beacuse the 2.5 OS has massive exhaust ports. Every time the piston passes the exhaust port the ring expands into the port a bit and then is pushed back in again. This constant movement of the ring means that its ends are constantly nagging at the locating pin/stake. On side pinned pistons the pin will eventually work its way out. On top pinned pistons it will eventually wear through, although this will take longer than the side pins take to come out. When this happens the ring then spins round gets caught up in a port and bang. thus before the pins falls/wears out the otherwise perfectly good piston needs replacing. Mercury pins are made from very soft metal. When John Marles (US1 on scream and fly) re-pins em he uses hardened pins so they will easily last untill the piston itself is worn and needs replacing. they just need re-ringing every 50 to 100 hour depending on how hard you use the motor. Just keep an eye on your compression.

Another cause of failure is injectors packing up but you just have to make sure you get em cleaned/serviced regularly. Just like the carbs on an XR2 really, they need servicing too or you may get a sticking float or blocked jet.

Other than that they're both just as unreliable as each other really.

Fix the 2.5 with John Marles top pinned pistons and get that MAD EFI on there. You know it makes sense!!!

Matt · 31-05-2005, 11:55 PM

This has to be the first thread ever to have the words xr2 and reliable in the same sentence.

JamesM · 01-06-2005, 12:08 AM

Jay Smith (Scream and Fly) sells 5 petal Sport Jet reed/cage assembly's for the 2.5 O/S. They maybe only 5 petal but they're bigger petals so the cages are just as wide and a direct replacement for the standard 7 petal setup. The cages are rubber coated and so seal better. This gives a crisper throttle resonse and improved idleing. Also the rubber coating cushions the reeds as the hit the cage and so they last alot longer than the standard ones.

http://forums.screamandfly.com/forum...=Reeds+2.5+260

If choose your compontents carefully you can build a longer lasting more reliable motor.

Cookee · 01-06-2005, 08:08 AM

XR2's need to remain standard for Offshore 200, Class III and the RIB formulau 1 class, the idea is to keep the cost down. It's now a 200hp class, so 260hp wouldn't be on really would it? :-)

roofer · 01-06-2005, 09:20 AM

cookee just like a rude high output wouldn't be on would it ?

Matt · 01-06-2005, 09:34 AM

Don't get him started!

Cookee · 02-06-2005, 07:48 AM

Quote:

Originally posted by roofer
cookee just like a rude high output wouldn't be on would it ?

What Matt said!