legacycentral bbs

Im going to be building a new motor for my 93 n/a legacy.

Im going to be using a T3 with a saab TMIC.

I was planning on using ej25 DOHC heads, but they seem to be impossible to find. I see a few old ads for them, and most of the time, they were already sold at super expensive prices.

If everything remained constant and I only planned on running say 10-12psi of boost, what would change if I used the
ej22t heads vs ej22 n/a heads vs ej25 DOHC heads?

If everything else remained constant, would there be any power gains to be had between the heads?


Danny

There are several threads covering head swap issues. Please search, and if you can't find the answer's you're looking for, post back.

Ive gone through almost every thread concerning 2.5 dohc. I really cant find any solid info. The threads I see claim a 20-25% increase in flow.

If everything else remains constant, and Im not looking for 300hp, will one head be "better" than the other, and why?

I dont understand why the head will increase power. If Im not increasing flow beyond the n/a heads capability, why would switching to another head increase power?

Will the 2.5 DOHC heads increase power if all else remains constant?

There are also a ton of ej22t heads floating around for cheap prices, and if I can do as well power wise on these, I might as well save my money...

Danny

An engine is an air pump. The amount of power it can make is directly related to how much air it can flow. If the heads one is using cannot flow enough air to make any more power, how big one's turbo is becomes irrelevant...

But you've got bigger issues that suggest using the Ej25 heads. That is your compression ratio on your Ej22E engine. Either you will want to use the larger volume EJ25 or Ej20G heads OR go to a lower compression piston. If you stick with your stock heads (which have been known on rare occassion with the right set up to hit 300chp) you will need to put Ej22T pistons into your block or get an Ej22T block.

And I don't mean to be rude, but if you are thinking that Ej25 heads are too expensive, you may be going down a road that you can't afford to go down. While one can do things cost effectively, I personally wouldn't try to under take a project like this on a buget of less than $1000, and would probably want another $500-1000 in the kitty as a "just in case" fund. This is doubly true if this car is your driver...

First, thanks for the reply Matt.

The legacy is a second car, but Im using it as a daily for the winter. Im buying a second n/a block and I am planning on building the motor.

I already have some ej22t pistons lined up.

I was also planning on spending about $1000 on the engine. I am trying to be VERY frugal, and if I can get away with the ej22t heads for 1/3 the price and still make the same power, whats the point of wasting my money?

So, I guess my question is, what kind of gains can I expect, all else being equal, with the 2.5 DOHC or early 2.0 jdm heads as opposed to the ej22t heads?

Danny

I dont see a 300hp build on a BC using ej25 heads happening for any less than 2000 or so, period, at least to do it right. and you could easily spend 3000 to really make it right. I priced it out the cheapest way I was willing to do it, being realistic and thorough and had to postpone the build. when you get down to it, assembling a turbo kit from scratch WILL nickle and dime you.
you could do a lesser, cheaper build by putting ej22t heads on an ej18, use a VF11or ford T3 and homemade hot side, small intercooler and emanage, that kind of thing.

I will have the small intercooler, ej22 long block, and pistons for about $300.

I figure seals, gaskets, supporting hardware, etc will run up to $400.

Heads, intake, injectors Im *hoping* to get as cheap as possible.
DOHC heads are around $250-300. ej22t heads are like $100 for a set.

3 Gauges, one with turbo timer should run about $250 used.

Im actually already running a T3 with rrfpr which will both make the switch over to the new motor.

If I decide to, I will buy a used emanage and have it tuned, but for now, its going to run off the stock ecu.

So, I definately think I can hold it under $1500 as long as I find everything at decent prices.

Danny

I knew you already had a turbo set up on there, and thus my lower number of $1000. I was a little tongue in cheek about it in my previous post, but once you get around the compression ratio issue, which it sounds like you are going to do with Ej22T pistons, the next issue you will encounter on your path to 300chp will be that teeny little intercooler and that turbo. 300chp on these old Leggies is full size TMIC, if not FMIC and TD05-15g, or at the very least vf8/12 territory...

Hehe, Im not really itching for 300 crank.

Im more or less trying to hit 200whp and anything over is just a really nice bonus.

Im almost trying to max out the stock ecu.

Jumping to another turbo, and piggyback or standalone is the *jump* Im trying to avoid.

What are the limits of the T3 and saab tmic?

Show me a boost map of the turbo you are using and I can run some numbers for you. T3 is a pretty vague description of your turbo. I don't have a clue how that thing is trimmed as it is not a very common turbo for use in Suby circles...

Oh, and 200whp will be +/-260-280chp depending on what sort of dyno you put the car onto...

Garrett T3 50 trim compressor, .48 A/R exhaust w/ internal wastegate. Compressor housing with machined tapered inlet, 2.5” elbow welded on and fitting for Idle Speed Controller. Compressor outlet with 2” elbow welded on.

Thats all the info I have.

Ive been doing some reading, and Im curious if anyone wants to comment on possible timing issues at upper rpms with 10-15psi of boost.

Well, this project *might* get a little more expensive soon. I found a vf39 for $275, maybe a little less if I can bargain him down...

I did happen to find STI yellow injectors for $100, so that helps my budget a whole lot.

I have to check and see what manifold I have to see if the vf39 will fit...

Think I should go for it?