G, 2L block and pistons with 2.5crank is just shy of 2.2

 

Just come across this site....
http://www.cgperformance.com/subaru_block.htm
Anyone seen it??

 

I've still got a lot to learn!
Thanks, Graham.

 

Not sure I agree with their need for a CDB if you use more than 10psi boost

And some of their other ' in general ' comments are a bit off the pace. But l guess we [ in the UK ] are a bit further down the modding road than these guys.

David APi Engines / APi Impreza
www.apiengines.com

 

David, the US and Australians were further down the road with tuning than US until very recently when we caught up, and by we I mean the few people like Mark, Pat, Paul and Andy who have really been leading the way in Subaru circles over here.

In the US the lack of an off the shelf Impreza turbo led them to becoming creative with what they had, an open deck 2.5 N/A engine with SOCH then DOHC heads. The 10 PSi boost is a cunning bit of marketing speak, basically the stock NA 2.5 was alright to about 10psi before problems with the rods and pistons set in, which after all weren't intended to be used with a turbo...once the US tuners got round to fittings decent rods and pistons they were well into the 400/400 teritory, however then they started finding the limit of the blocks...Crawford went down the wise route of working with the closed deck 2.2 litre EJ22T block, Cobb went into making their own semi closed deck blocks, welding up N/A EJ25's, and these guys explored another route.

You have to remember that in the States, Subaru engines have long been popular in air cooled VW conversions, Sandrails (look at the Crawford and this CG bunch's websites) and aero engines...a lot of them were experimenting with big power turbo charged Subaru engines long before the Legacy and Impreza Turbo come on the scene over here!

 

What are the best forged pistons for the usa 2.5, and does that make the engine more stable at revs over 6500?
Are the pistons the weak link as iirc the crank/rods are good, just weird pistons.
Graham.

 

i thought mark at lateral does a good deal for the 2.5ltr block with uprated pistons????

 

GGR have a stock 2.5 on Eb@y @ £1250 (about the cost of MarkA's GB?) but if you need forged pistons/rings then I wonder what the on-cost is.
Wish Lateral would actually get its web site up and detailed!
Do you think the rods are up to 1.5 bar and 8K rpm?

Graham.

 

Rods and crank on the N/A engines are the same as found on Turbo engines, but that still doesn't make them bomb proof, well at least in the case of the rods at least.

When you say the USA 2.5 Graham, do you mean the EJ257 2.5 Sti engine, or the N/A 2.5 EJ25? If you mean the EJ25, this is the same engine found in 2.5 Legacies sold in the UK. Either way Mr. Lateral sells a forged pistons that have been specially developed for 2.5 engines running 2 litre heads.

 

IMHO stock subaru rods at 8k rpm and 1.5 bar is pushing it a bit, and asking for trouble!

 

The rods we use take 8000 rpm, no worries, but you'd need our competition shells on the crank for those revs, probably NOT the ones in the EJ257 as standard.

We use CP pistons and have the crown machined for compression and also for compression bowl shape. They take original Subaru rings and piston pin clips. Some of the Yank stuff uses 'perfect circle' rings which we have never rated or had any success with.

So where's the use in buying a short motor from anyone and then throwing away the rods, pistons and shell bearings?. All you are left with is the bare block and a standard crank. Doesn't seem much of a deal for £1250.00 to me !!

David APi Engines / APi Impreza
www.apiengines.com

 

Tim, I am aware of all that. We have been supplying engines for Subaru 'projects ' for over 21 years as APi Engines.

Even in 1985 > 88 we were asking the question, would you want to fly in the air using a Subaru engine as a sole means of propulsion??


What you have to remember on the welded up blocks is that there is heat transfer whilst welding. My opinion is that the open deck cylinder will 'walk away' from the localised heat when welding it up and l would be VERY surprised if the bore was still perpendicular to the crank.

David APi

 

PMSL, nice one David, wouldnt fancy droping a big end at 32,000 feet

 

Conrad, from the look of the photo's of the contraptions these engines were being fitted to, they'd be lucky to make 32 feet.

Still too far to drop in my opinion.

David

 

David, it's all down to the work carried out before and after welding...one method is to heat the block up before welding, and the temperature cycle it afterwards...of the top of my head I can't remember the exact details of the process (temperatures, time scale, cooling etc) but welding up the deck does work, as Paul has proven with his 2.5 closed deck block, which IIRC was cryogenicly tempered after welding

 

suddenly relinering a 2.0 cdb looks like a wise move.

or,.............
















we could all just settle for 300/300, now theres a good idea

 

Bugger that idea Andy, after 3 years I got got used to 350/310, it was time to move on to the next level

 

Yes, @ 370 x 340 ish I'm used to the rush of that now after 9 short months which will have to be ok for next year too.
However, this time next year I hope to be doing Phase 3 of the engine.

Taking David's points though: if a 2.5 is to be maxed out (ie 450 x 400) then the cost of a bare 2.5 block with liners and a 2.5 crank must still be over the USA N/A 2.5 short block?

At this rate, if I wait another 12 months I can buy an Sti 2.5 V9 whole engine (and 6 speeder?) and squeeze that all into my V3 Sti for a 'good price' from a salvage car. Get a twin scoll too (which I guess is a better turbo than the TD05 20g).

For hill climbs I really need to see a lot more mid torque over my current 370 x 340 2 liter.My main rival this year is the EVO V @ 450 x 400.
What torque has been seen out of a 20g 'level' 2.33?

Graham.

 

Graham

The twin scroll will make similar torque (and earlier) to the 20G but less top end power, there are hybrids available which push the T/S a bit higher but the limitation is with the original twin scroll exhaust housing which is just too small for big power.

I'm involved with the tuning of John Stevensons hill climb Scoob, last year he ran an Axis EJ257 with pistons/rods, 20G, Link ECU and cleaned up in his class (modifieds)
Next year he is using a similar engine EJ257 with uprated pistons and std rods but with a twisted GT30R ex John Banks (my old one) and Apexi ECU.
If kept above 4k rpm the 30R is a monster in comparison to the 20G as in 80-100 bhp more.
If going 2.5 then I would recommend GT30R to allow a greater rpm range at full boost, the 20g or twin scroll vf36/37 need to be tailed off at the top end on a 2.5. Very nice on the road but not what you need for competition.

Andy

 

any one heard of this scooby company in ireland stubbled accross it when i was doing a search into 2.5 litre lumps just wondering if this a decent price and if they are a decent company

 

sorry for got to add link !http://www.stiuk.com/products_info.asp?id=202&cat=56

 

Reckless: Same product on Eb@y form GGR @ £1250 collected.
Andy:
Thanks for the info, The 2,5 engine seems to be the only fix to my 'EVO 5' problem in the Midland Championship.
What torque would John's engine develop do you estimate?
Graham.

 

When it was attached to my 2.3 it was IRO 460lbft over a wide rpm range.

Andy

 

A gearbox shreader!
Graham

 

At the wheels though wasn't it??

 

AndyF "If kept above 4k rpm the 30R is a monster in comparison to the 20G as in 80-100 bhp more."

I must admit I'm really looking forward to next year, the car should have moved on technically by quite a jump, should be lighter by quite a margin, and faster...by definition

Andy's input and advice has been invaluable this year as has his patience, with my in-opertune anoying phone calls recently must have been a pain. But the whole thing now feels as if it is coming together.

Still recon I have a chance of getting under a tonne, and with a bit of luck 500+ BHP (with associated torque).. should be good.

One of the more important developments should be the inclusion of some decent diffs, as last year the big lesson was traction is a huge problem, standard RA open front, viscous centre and viscous rear. ATM it's looking like, torsen front, uprated 30 lb/ft STi viscous centre, and plate rear.

I'm even toying with trying to learn to drive in a straight line, and use it on the odd drag strip, just for fun... reason being I'm not likely to get a shot at championship honours next year, on account of that contageous disease my wife has caught...... Pregnancy ( no sense of timing either).
I have an ideal model for "Escooby Ecosse" this year though, might be a shock to some of the members

Media Relations: John Stevenson (F.Ann.Y)
Chief Designer: Andrew Forrest (M.I.eng-Aids Branch)
Chief Medical: officer John Banks.(Struck off, he said a detatched limb, was a virus, alledgedly he has learned from this)
Chief Tactical officer: T-UK (have cold barn, can't travel )
Head of polishing services: DRB5 (How shiney is that... now)
Team principle: John Stewart...(Cause he has the contacts)
Team Bevvy Provider: AlanG...( Cough..honestly, that's Home Brew, Tennents...Never !! )
(Agent MacSlooby... Shhhh !! the Sassenachs don't know about him, how could they with a cover name 'Timothy' and he looks 'soft'.


---john---

 

LOL...that Quaife is still heading for Kent you know

 

John, that kind of 'planning' you are about to incure the fruits thereof needs 2 sign-offs, and, at the outset, few, if any, other Team members are involved..

But to have a bouncing baby at the mid-season point is Not Good, but it might just fall at the right time, mid week ( ).

500 bhp/tonne sounds really good, few cars in our class can muster those stats with EVO's coming in at 1400Kg/480 bhp ish in general.
In the Sports Car Class, there are 2 short wheelbase Audi Quattro's running 1000Kg x 600/700 bhp, but they are not allowed in the road going section.

I have the same diffs as you and traction even at my level is awkward, but that is the suspension as much as anything.

Good luck with it all, I hope you will give us some insights along the way 'to delivery'! (of the car).
Regards, Graham.

 

Just looking at videos and you can take 0.2 seconds from your launch no trouble at all. Just looking at the attitude of the car, and the initial motion, it's quite gentile so far, and this probably explains why you still have a gearbox and clutch. I think you over estimate the normal levels of grip at the pod, an abrasive normal tarmac surface is normally grippier than the pod unless the properly glue it, and that is rare.

I would like to get on the hills next year, not a whole series but 5-6 would be okay. I would like to see how the drag strip performance translates.

Paul

 

Thanks Paul.
The new Championship will be right up your street in 2006, and all 'southern' based too.(see Motorsport Section, Terry B)
Got any video from Elvington as to starts by you/Andy/P20 etc??

Must admit to being a bit bothered about the longevity of the box as I have to drive the car home from the events too.
I can possibly make up the 0.2 along the way in the 60 seconds it takes to climb most long (1 mile) hill climbs.
Do you think real hill climb Avon slicks would finish the box off (stock V3 box) with the engine @ about 380 x 340?
Graham.