TD06 is good, not tested in the UK on a 2.3-2.5 litre yet but soon There is a surge issue on a 2.0 over 1.4 bar, but on the 2.5 I think it would be superb at 1.4 bar with good spool and little lag.

 

there are also 4 valve heads for the ej25, i have a set in my garage

 

I guess that's what my tuner meant, the double camshaft EJ25 head. I have no idea what an EJ25 head looks like, but if you have one in your garage that would allow double cams, then I guess there is such a thing

 

Phase I EJ25 heads are DOHC, Phase II are SOHC if that helps.

 

So, John, you're saying one needs a phase 2 EJ25 bloc and a phase 1 EJ25 head?

 

Thanks for the email, Adam You have Mail back

EJ25 bloc and phase 2 EJ20 head?

 

I think you can swap the heads about at your leisure, but I presume you'll need to think about decompressing it for a turbo application.

 

Yeah but Adam tells me that the EJ20 head is better suited for turbo applications as it is dock (not sure what that means?).

Surely if the engine has as much capacity as reliability permits and the head flows well, you can use a bigger turbine and still make lots of reliable torque and power with low(ish) boost? That's what I'd like to do; about 400 ft/lbs and 450 bhp, just to cruise around in a sleeper with good top speed and acceleration

 

Talking about compression, what compression would you recommend? About 8.3:1? More? Less?

 

I am using standard subaru compression, 8:1 - seems fine for me.

 

Claudius, yhm.

 

Standard phase 1 ej25 has a 99.5 (or .6 ) bore, my new pistons are slightly oversize.

Phase 1 is also twin cam - but looking at the design I went for phase 2 turbo heads. If you reckon the phase 1 ej25 heads are better, make me an offer...maybe you want the bloody horrible inlet manifold too?

I'm going for 8.5:1 comp ratio.

Gearbox strengthening is a must at this level - I stripped 3rd very quickly when I switched from winter tyres to Pirelli P-Z Corsa's with 'only' 360 hp out of current engine.

Also don't forget fuel delivery - I'm opting for 550's and an adjustable regulator which I hope to squeeze my target with. And a suitable ECU to run it all with - I'm going to be bloody minded and use the original JECS, but it will likely cost me plenty of time getting the MAF scaled correctly to let me hit my targets.

I also ended up buying 2nd hand heads and inlet manifold plus new flywheel and clutch plate, specifically so that my car wouldn't be off the road for so long - would be a shame to rebuild an engine and not fully port match & balance everything

You'll be selling your Evo soon - and you'll definitely need to attend a couple of Streetcar-Cup events....just to p*ss Richi (cirpower) off

Richard

 

There are a few Roger Clark builds running about 8.5:1 approx on 2.0 litres and the owners rave about them.

 

Eberybody is telling me about 2 litre or 2.2 litre or 2.33 litre.

But I'M A STROKER BOY so what about the big capacity?

What about the "no replacement for displacement"?

What are the disadvantages of running 2.5l or more?

 

I agree see my thoughts in your gearbox thread sorry for the ramble!

 

The only disadvantages of a 2.5 are to have one that can safely rev over 7k rpm with bigh power (ie over 500/450) you ideally need to do some serious work in the crank department...which would cost around 1k GBP + just for a billet crank

The storcker kits available from Jun and a alike are I beleive reground standard cranks with unique rods...so in theory they could possibly be weaker than a standard crank!

 

I have a Jun stroker kit in my Evo and I GUARANTEE it is not a reground standard crank, it's a forged piece of metal, with a heat treatment and coating and God knows what. It looked awesome and was much heavier than a standard item, there is NO DOUBT in my mind (as GWB would say ) that it is completely different from a standard crank. All the mechanics and engine builders / people who saw it were speechless

I dont know about the Subaru kit, but I would assume it is the same type of quality.

TODA is crap, but I'm not talking about TODA.

 

What would you set the rev limit to on a Lateral 2.35 guys?

 

8000rpm, but Im mad and signing a disclaimer.

Depends on heads, cams and valve springs really (IMHO)

7500 if you want to be conservative.

David

 

on my 2.5litre engine, my rev limit is at 8000rpm - seems to handle that fine.

 

I was thinking 7500 RPM or 500 RPM higher than peak power whichever is lower.

It will have STi 5 heads, it is more the bottom end I was thinking of with the longer stroke.

6% longer stroker ~ 12% high conrod loading, so if the standard stroke is good for 8000 RPM soft rev limit, then that would suggest 7150 to me for the start of the rev limiter. I suspect it will all be over by 6650 anyway.

I am ignoring the extra weight of effectively 2.2 over 2.0 pistons, but the Lateral ones are 14% lighter than EJ20 STi pistons so that pretty much cancels out I think with a little margin for safety.

How heavy are aftermarket steel conrods compared with OEM?

[Edited by john banks - 4/29/2003 10:46:58 AM]

 

Good thinking about the rev limit. I think aftermarket steel rods weigh about the same as standard rods; very expensive ones may be slightly lighter.

 

dock means a typo, think I meant DOHC.

 

claudius,

You are missing the point,

the 2.5 and the 2.33 have the same stroke, so your being a stroker boy makes no difference.

The 2.5 gets its extra capacity from the fact that it has a 100mm bore (99.5 + 5mm over bore) as opposed to the 96.9mm 2.2 block.

So the extra torque you mention that comes from the icreased stroke is present in both, plus the 2.5 will generate some more from its capacity.

Theoretically ideal combustion chamber size is between 350 and 450cc, so the standard 2.0 is over the limit, it gets worse as you move up, you have to decide what you care most about.

people say 2.33 as it is far easier and cheaper to get a 2.33 in closed deck and oil squirting variety than it is a 2.5. Given the results people are seeing from 2.0s at the moment, I cant imagine you would be dissapointed with a 2.2, never mind a 2.33 or 2.5.

I would not be keen on a 2.6 due to the way in which these kits achieve their greater stroke.

Stroked ej engines engines already have the problem of the lower piston ring crossing the gudgeon pin access hole which can promote wear, I would not be keen to push this further.

The rev limit comes from the theoretical rule of thumb re piston speed. Generally people say dont go beyond 4000feet/min. This equates to about 8000rpm on the 2.0 and 7250 I think on the 2.33 and 2.5 (same stroke remember).

This rule of thumb of for engine manufacturers and with uprated internals you can more than happily exceed this guideline as the quality of the build and strength of the rods should be able to cope with the extra strain. On top of this the aftermarket pistons are lighter even than the 2.0 sti forged pistons.

Some would say this is really another reason to go for the 2.33 since the piston diameter of 96.9 instead of 100mm does make a significant difference to their mass, so again you have another safety margin built in when going for high revs. I think that my set up is strong enough with a 2.5 litre capcity for more than 8000 rpm so I amnot too worried.

Saying that, on the road, depending on power delivery I may consider incorporating a soft rev limit at 7300rpm. I cant imagine I will be using the top end that much anyway since I have specced a smaller turbo for drivability.

another thing to consider is that as well as the increase in maximum revs possible, the geometry of the engine with the standard 75mm stroke is more conducive to revability than the 79mm stroke, but we really are splitting hairs here, when you consider the evo has an 88mm stroke apparently. (should check that one!).

 

So you think my 9000rpm rev limit is too high then adam?

Joking aside, I think TOTB will see a scoob engine over 9000rpm.

There is a substitute for capacity, it's RPM.

Paul

 

but rpm does not equal drivability.

I also think my internals would cope with 9000 rpm.

just depends if the cams would cope up there! doubtful in my case, not so in other peoples!

 

s2000 is driveable, but with vtec I suppose.

EVO manages quite well because the conrod is nice and long, so reducing the peak acceleration despite high mean piston speed.

Claudius can always buy my 2.5 engine!

paul

 

There seem to be a few 2.5l engines for sale, I got several emails already! I am interested and I reply to all of them. Email me!

I agree the "squarer" the engine is, the better it revs theoretically, but I am not that concerned with high revs, I like the torquey feel from 4000 to 6000 rpms.

The only time I need revs is to reach high speeds on the motorways. Can anybody tell me what speed his stroker is doing at x rpms in 5th gear? Can you reach the rev limiter in 5th gear? Trying to find out the top speed here (not because I want to do top speed often, but just out of curiosity).

Thanks

 

I didnt know that. Why is that? You are probably right, given most V8s are 4 litre engines, but how come?


I'm not so sure about that. I am not impressed with my Evo, it's good, but not impressive. Has got 410/410. I guess I should change turbos! LOL

The torquey reliable scooby I'm trying to get together wont be for myself, but for my brother, who is more of a normal guy than myself and will be happy with 400/400 or 450/450; I can always lower the boost a little, the main thing is that it is RELIABLE.

 

if you want a greater chance of lasting, then it really should be a closed deck block, and starting with a 2.5 this is difficult. people are offereing them to you yes, but they will be open.

Pauls might be closed depending on how he has been getting on, but he isnt selling, he is just having doubts.

Stick with it paul!

the ideal combustion chamber size is something i have read somewhere realting to engine theory, the better man to ask on this would be paul. i am sure I could pull something off the net as I have done before, but Paul knows this kind of thing first hand.

It will be related to flame propogation speed, combustion efficiency and the like.

with regard to engine speed, forget the stroker nonsense.

the only thign that will affect engine rpm at a given speed is gearing.

Assuming a car can reach say 160mph, whether it is strokde or not, it will be doing whatever rpm it is doing because the gearing dictaes that it must be.

if you want the gearing of the lateral performance synchro ste, thee can be provided quite easily. I used to have a spread sheet but I believe it was lost along with my harddrive, am sure someone else can be of service.