2.2S to 2.5 on MFI - help please?

[sspencer]

Guys,

Does anyone have any information about my engine.

Its as 70 2.2S that came up to Sydney from Melbourne in 2005 after a rebuild that extended it to 2.5 (apparently), the guys at Autohaus think it probably is a 2.5, turning out 180hp. The engine number is 6301272.

If nobody has any information on this, another question would be - what would have been done to take it to 2.5?

I understand their was a special engine in some ST's that were taken to 2.5 by a longer stroke crankshaft on a 2.4. So if this started as a 2.2 - is there consensus on how it would have been taken to a 2.5?

Thanks, Stu

[alexwebster]

Would have had 2.7 or 2.8 barrels and pistons to make it 2.5. the short stroke of the 2.2 crank gives this result - i think!!!!

It is essentially what they call a short stroke motor. They can be very 'cammy' meaning that they love to rev and make it all up top. However this can be tuned out with cams and valve size.

I will let the other experts chime in!

[Fishcop]

Stu, there's some pretty good threads on Pelican about the 2.3 and 2.5 ST engines and how they are/were built.

Cheers

[CamBiscuit]

Stu

If you are able to see the markings on the base of the barrels it will help determine what you've got.

[OBRUT]

most 2.5's are based on a 2.0/2.5 66mm crank with 2.7 barrels and pistons. lots of good info in bruce anderson's book and wayne dempsey's (pelican owner) book.

however, if 'common/regular' say 8.5:1 2.7 pistons are used then you end up with a pretty low comp engine (about 7 or 7.5 from memory). the +ve is such an engine will run well on any fuel without issue. downside is relatively low specific power.

a hot 911 motor with high compression etc will approach 100hp/litre. if you're making 180hp from a 2.5 then this may be what you have.

[sspencer]

Thanks - and DNF @ Wakefield - & Racelogic?

Alex, John, Cam and Ryan,

Thanks for getting back to me. Some great intel there.....(although couldnt find the 2.5 reports on the PP forum?)

I have been a bit quiet recently as the car had its first DNF at Wakefield Park.... so was lying low... An expensive "flat bed" back to Sydney, and Bob Whymms identified it as the Ball Pin in the clutch shearing. A $60 part... but lots, lots more than that to replace it!

Anyhow, every cloud, etc. So I decided to get a major service, MFI belt and drive replaced - a full tune up - and get it on the rolling road to get a "true" perspective on my thoughts/your comments around a 2.2 to 2.5.

Outcome is 200HP for the 2.5. Not bad for a 39 year old girl.

Also used the Racelogic box for the first time at Wakefield. Interesting to see the different split times/speed etc in all corners for my car versus the laps we did in my father in laws 1987 3.2 SuperSport.

Has anyone else got a racelogic performance box? Its a great way to revisit your day... (although make sure you delete the DNF lap)

Thanks again, Stu

[alexwebster]

Hey Stu,

I have had one for about 2 years now, and they are great. Apart from giving you your times straight away, and relocatable into another car in seconds, they are great on the road too!

Taylors^2 have them also!

Great to hear that the 2.5 is putting out the hp that you think it should be!!

[reedminor]

Out of interest Stu, what power did you have at the rear wheels?

John Shingleton and I attended at tech day at Bob's last year and ran our cars on the dyno.

[griffiths_r]

not getting competitive justin?!?

[reedminor]

Heaven forbid Richard... of course not.

[CamBiscuit]

Stu

If you are on Pelican try searching 'short + stroke'.

Assume that's 200hp at the wheels?

Cheers

[sspencer]

Hey Alex,

Have you used your Racelogic at Wakefield? If so any perfect laps you want to share so that I can load into the software, and trace where I am loosing time? :-)

I only managed 10 laps in mine, I think the best was a 1.19secs, but never did a good lap really, so there would be a far bit left in reserve there 3 secs mmin I would think. Managed a 1.21 after 4 laps in my father in laws 3.2 SS, so again lots left there.

What tire pressures would you run?

Cheers, Stu

[sspencer]

Hi Justin,

The car produced 110KW at the wheels which Bob equated to 200BHP. From my reckoning thats about 150BHP at the wheels, and then you loose a third throught the dive and gearbox - so would equate to the 200bhp.

What did yours do?

Cheers, Stu

[reedminor]

106 Stu....

Not bad for a little 2.2.

Bob's first question (accompanied with a big grin) was "is that a 2.5 you a running!?"

[matt911]

Stu, that sounds like a fun little motor you have.
As far as Wakefield goes, the best thing to do is get in as many laps as you can. I have only done about 4 or 5 days (250 - 300) laps there and pick up time each day. Im still learning heaps! My little 2.0 T puts out about 89hp (60kw) at the wheels, and with a little suspension work Im getting in the mid 1.17's. I still think I have a second or two. Assuming you are running R' spec tyres, most people run about 26, 27 psi cold, heating up to around 31,32. I hear other guys using different pressures, hopefully others will chime in.
After doing only ten laps, you will shave a massive amount off your current times.