RoyC

Has anyone fitted the PE manifold to give 20-25 bhp? I have exhaust & induction kit and boost upgrade on MY99 UK and I'm thinking about the manifold now. I know it's a bit dear but if any-one else has done this I would appreciate how they got on.

Area 52 Autosport

Hi Roy

Putting equal length manifolds on the car will not give you 25bhp. More boost gives you 25bhp, not an exhaust system.

A good exhaust system will up boost very slightly but not 25bhp.

They change the sound of the car. You will lose the flat 4 throb and beat, the sound will all love in the Impreza.

Equal length manifolds are for very serious engine builds not std cars where their primary purpose is heat dissipation, not horsepower.

We sell them but would not recommend them for anything other than a serious engine build.

Kind regards

Ben

pat

Roy,

I know that the figure measured by PE for the equal length manifold was on a 22B... not sure whether you'de get the same sort of gain from an EJ20 block...

I don't know of anyone else with an equal length manifold on a UK car... I'm sure that PE could advise on this one; perhaps TDI have fitted some?

Ben,

It is possible to achieve 25BHP with a decent exhaust system... if you set it up right you can increase scavenging by a large amount and in some cases even get the VE beyond 100%. But it all boils down to *where* on the power curve you measure the gain! If you're talking peak power, then getting 25BHP would be possible, but at the cost of lower end torque which isn't ideal. If you're talking about the tuned length of the headers then you may well see 25BHP *at that point* relative to an untuned manifold. Swings & roundabouts.

A good exhaust system will increase boost if it can increase flow through the turbine. But let's not forget that it is still under the closed loop control of the ECU. The areas you may notice a difference are at the low end (better flow allowing the turbo to spool up sooner like the downpipes) or at the very top end, where a freer flowing exhaust system may gain a few BHP... 25BHP ain't gonna be easy though.

Theoretically the equal length headers should alter the sound of the engine.... one of the reasons it sound like it does is due to the vastly differing header lengths... just how much of a difference it will make I've yet to hear... [this weekend, hopefully...]

Not entirely sure on your point w.r.t heat dissipation. The point of equal length manifolds is to give a large torque boost at a certain engine speed by allowing a pulse in the exhaust system to over-scavenge the cylinders. For a nice flat torque curve, you'de choose unequal length headers, to spread the torque peaks... equal length jobs will produce a nice torque swell; now if you can get that to coincide with the revs you normally fall to when chaning up, you're on to a winner :-)

Point about serious engine builds taken. To get the best out of one of these (beautifully crafted, and rather expensive) units you'de need a good strong bottom end and gas flowed head.... [hmmm... that could bet taken the wrong way ;-)]. Still, even without that you should still see an improvement on a free-flowing car.... bolting it onto a completely un-modded car probably won't do much (apart from make the bay look pretty :-)]

Cheers,

Pat.

Ian Cook

They make the car sound crap though, you lose the lovely flat 4 burble, makes it sound like a pinto engine ?

firefox

Cheers Ian

J.

Ian Cook

Dont take offence J its just the noise i dont like, it obviously makes a performance difference, or you wouldnt have fitted it

MorayMackenzie

Pat,

Just to be pedantic (what a suprise eh? ), isn't the 22b actually built on an sti 2litre BLOCK, so doesn't that mean it is, in this sense, an EJ20 BLOCK?

Moray

Adam M

Moray,

what was the point of that?

we all know how clever you are!

MorayMackenzie

Sorry Adam et al, I didn't mean to annoy, I was just in a strange mood. I'll just get my coat.

Adam M

Taxi for 1 please.

MorayMackenzie

Adam, If I could find my pink handbag, I'd raise it in your general direction! (Vic Reeves style).

[This message has been edited by MorayMackenzie (edited 02-02-2000).]

RoyC

Thanks for all your replies - don't be fighting over it though!!!!lol

pat

Moray,

if you want to be pedantic, yes, the 22B block is based on the EJ20 block; it's basically a bored out version. However, Subaru seem to have made new castings for the 22B, so if you look at the block on a 22B you will see the magic letters "EJ22" and not EJ20.

Cheers,

Pat.

firefox

Howdy...

Are you sure its not a block off the Legacy 2.2 ? lol



J.

AlexM

A question for the anoraks (sorry - detail orientated enthusiasts!) -

Can anyone post bore and stroke measurements
for EJ20 and EJ22 (22b) motors?. I am curious as to where the additional 200cc comes from - bore or stroke increases, or a combination of both?

Does the JUN 2.2 stroker kit get the extra capacity from it's new crank and rods, or do they also overbore the block?

Ta.

Alex

P.S. apologies to RoyC - completely off the topic, I know...

pat

Firefox,

Could have come from anywhere... [well, I can think of places it definitely didn't come from, but let's not go there]. But it's still essentially a bored out EJ20 block which has the cute label "EJ22". In any case, the benefits you'de gain from a equal length manifold will change depending on the capacity of the engine [as well as other "minor" things like head design :-)]

Cheers,

Pat.

MorayMackenzie

I suspect a stroker kit would gain the extra capacity through a longer stroke (and maybe shorter piston heads and a big gasket as well). I thought that this is how the 22B works, using a 2litre block with longer stroke internals, hence the greater torque to horsepower ratio modded 22b's seem to get over standard 2litre STIs.

I would like to know for sure, but, as with many of the technical details on our scoobies, there seems to be a fair bit of secrecy or controversy surrounding the issue. Has anyone out there got a definite answer which has been proved? If so, would you share it with the group, please.

Moray

alistair

PE have a dyno, so do a before and after run. If it doesn't give the claimed 25BHP then negotiate a price accordingly !

pat

Alistair,

You are positively crafty :-) I think this might be well worth looking into... after all if they claim it will give 25BHP *every time* it must do, or they'de be in deep ^%$"^ with the ASA...

Alex,

The EJ20 has a 92mm bore with a 75mm stroke. The EJ22 has a 96.9mm bore with a 75mm stroke. The extra volume comes from bore alone.

Not sure about the JUN stroker kit, but I would be surprised if they bored the block. The TDI kit doesn't appear to involve re-boring [but re-mortgaging :-)]

The trouble with stroker kits is that they will increase the wear on the engine, especially the pistons since the engle between the con rod and the piston will increase, compared to the standard crank. The EJ22 avoids this yet still provides substantially more torque.

Cheers,

Pat.

Anders

All these 22B details and more will be appearing at a web site soon

I have said it before but 22B.COM is nearly there!

The video download vault is being developed with Mr Scooby Trax Chris Coulsdon

My car is heading for an end of Feb release date!

AlexM

Anders -

Hope your engine build goes without a hitch, and its up and running soon.

Is it going to have any 'trick' bits?.

Pat - so is the EJ22 an overbored EJ20, or a new casting? If so I presume it is a derivative of a Legacy 2.2l motor. Just curious....

Cheers,

Alex


[This message has been edited by AlexM (edited 04-02-2000).]

Anders

22B is a new casting, when Auto Sportif blew an engine they had to rebore a "2L rally block" as there are no remaining 22B blocks in existnece. Something to do with the 16UK 22Bs I think and the other 8 that went to Australia and USA as "Show cars".

My 22B is going to be significantly "over engineered"! Now we are down to 97 RON I am not taking any chances with fueling problems again.

Area 52 Autosport

Hi All

The 22B is bored, not stroked.

Pat,

Close but no cocunut! Everything you say has merit (reference your first comments) until you stick a bloddy big turbo in the way that gets in the way of all that beautiful tuning.

For everbody's information, the equal length manifolds when put on the 22B made no more power on the car at all. Only when the car was mapped did it start to have an effect.

This is not the first time this happened. If anybody has read the article in fast WRX magazine you will know that AVO put tuned length headers on the car and it rsulted in a drop in power.

Mr Wilson then went on to say that whilst it shouldn't be classed as definitive it does just go to show that there are other reasons why you could consider using the equal length manifolds, not least one of heat dissipation. Less heat = more reliability.

Stroker kits are a big no no as well. The Impreza rods are really quite short and to shorten them still is asking for trouble due to the increased angles required and the subsequent stresses on the bearings, small and big.

Kind regards

Ben

[This message has been edited by Scooby Mania (edited 05-02-2000).]