N/A power

greg donovan · Post by **greg donovan** » Tue Oct 07, 2003 7:10 am

i have asked this question on other forums before and some of you are members there too so bear w/me please.
i and a friend are going to build a phase II ej25 block w/ej22 heads. the heads will have performance valve job and clean up. we allready use premium gas and would probably put a water injection system on if we could figure one out for a N/A engine. the big question is will the timing change and does anyone know of a way to adjust it if we need to? we arent too concerned w/top end power. in fact i want more torque earilier for rallycross.
greg

Post by **Legacy777** » Tue Oct 07, 2003 2:19 pm

I don't see why timing would change unless I'm completely missing something.

As for modifying timing, the only thing you could modify would be ignition timing, not valve timing. To do that, you'd need an aftermarket tunable ECU.

vrg3 · Post by **vrg3** » Tue Oct 07, 2003 3:05 pm

I thought I remembered hearing that a phase II EJ25 block with EJ22 heads will have very high compression. I would think that would affect base timing at least, if not advance.

Josh is right that you need an aftermarket ECU to control ignition timing. My brother is currently experimenting with a Haltech IG5 unit, which is basically a standalone ignition-only ECU with a few other outputs (it doesn't do fueling at all). It seems pretty cool.

THAWA · Post by **THAWA** » Tue Oct 07, 2003 3:11 pm

What about the other way around? An ej22 block with ej25 heads? Does the compression still go up or does it go down some?

vrg3 · Post by **vrg3** » Tue Oct 07, 2003 3:22 pm

I think it would reduce the compression ratio; some people use EJ25 heads on EJ22T blocks to get low compression.

greg donovan · Post by **greg donovan** » Tue Oct 07, 2003 4:53 pm

we have an idea for changing cam timing by taking the cam pulley and rotating it 180 deg. and machining in a new key way to advance/retard the timing as needed. how much would the haltech ignition ecu setup cost. we are trying to keep costs low to find an affordable alternative to turbo charging. we feel we can do this for under 500. any more and we might as well get a wrx front clip and do it right.
greg

vrg3 · Post by **vrg3** » Tue Oct 07, 2003 6:43 pm

How will you control the valve timing with that setup? If you're going for low cost I don't think you need to mess with the valve timing.

I think my brother spent about $200 on the Haltech setup, which is kind of expensive... If you're trying to do this on a budget I don't know what you'd do. You can't really trick our ECUs into timing differently very well because they try to learn around it. But with premium fuel you might find that the ECU does okay with its learning.

greg donovan · Post by **greg donovan** » Tue Oct 07, 2003 8:43 pm

it would be a one time advance of a couple deg. it is an attempt to make adjustable cam pulleys like the hondas and every other make of car have in the aftermarket. probably wont bother though.

no one sees this as a really stupid idea? we wont make huge power gains. we are expecting it to be in between a 2.2 and a 2.5. the car allready has 2.25" cat back exh. w/2 resonators. would add perrin pulley and panel air filter. maybe bore out the throttle body.

how much do the old legacy ecus learn? will the haltech set up work around that?

our idea is to use a haltech fuel controller to control a water injection setup to run of throttle position.

off topic: what about using the 2.5 crank on the 2.2 block? no boring just stroking and balancing. what else needs to be done with the stroked setup.

vrg3 · Post by **vrg3** » Tue Oct 07, 2003 9:52 pm

Ah, I see what you're saying about the cam pulleys... Sounds like it would be more trouble to do it safely than it's worth.

The ECUs learn a fair bit. They start with a conservative (i.e. relatively retarded) base timing and continually try to advance a little bit, seeing if it can be done without knock. If there's no knock, it uses the advanced timing as the new baseline. So it's possible that it could end up with decent timing after a little bit of learning time.

The Haltech IG5 system isn't a piggyback system; it completely replaces the stock ECU's ignition control.

My brother is planning to adapt the IG5's boost control output to control methanol injection in his car.

greg donovan · Post by **greg donovan** » Tue Oct 07, 2003 11:33 pm

what is the vehicle/engine combo your brother is using?

we have come to the same conclusion regarding the cam pulley. to much hassle to do it right.

so the factory knock sensor is pretty good then?

greg

Post by **Legacy777** » Tue Oct 07, 2003 11:34 pm

Yeah I'm pretty sure the EJ25 heads on the EJ22 block will reduce compression ratio. Not sure how much though.

vrg3 · Post by **vrg3** » Wed Oct 08, 2003 12:18 am

My brother's got a 1985 Supra with a JDM 6MGE engine. He turbocharged it and is using a semi-homebrow ECU (MegaSquirt). Hopefully this weekend we'll actually get it all running with the Haltech.

People argue about how good the factory ECU's timing feedback loop is, but there's no question that it's very dynamic. It does try to learn the "best" timing as you drive.

greg donovan · Post by **greg donovan** » Wed Oct 08, 2003 3:26 am

is it possible to hook up a scanner to see what the timing is at now?
the ecu must be very dynamic because after cruising on the highway at 75 for a couple hours the car is a little sluggish on the first few starts.
greg

vrg3 · Post by **vrg3** » Wed Oct 08, 2003 3:33 am

The only tools out there to do that right now are Subaru Select Monitors, as far as I know.

greg donovan · Post by **greg donovan** » Wed Oct 08, 2003 3:48 am

so my mechanic at the dealership could check that out for me? a little spendy just to gain info i know but cheaper than another engine!

you dont even think the haltech would be necessary then either?

my frind has a tt supra he converted to single turbo and it runs in the low 11's.
cool but i still dont get drag racing.
i like the gravel!
we had a impromptu rally drag between a 4wd s-10 blazer w/small block 350 and rally tires against a group n wrx and it was split at one win each. pretty funny after a day of rallyx clumps of grass and dirt flying everywhere!

greg

vrg3 · Post by **vrg3** » Wed Oct 08, 2003 4:01 am

greg donovan wrote:so my mechanic at the dealership could check that out for me? a little spendy just to gain info i know but cheaper than another engine!

It's possible he could; believe it or not, there are some dealerships that don't have the appropriate Select Monitor tools, particularly for older models like ours.

you dont even think the haltech would be necessary then either?

I'm not qualified to offer an opinion on whether or not it's necessary. I could easily imagine it either way. I just brought up the Haltech IG5 as an example of a relatively cost-effective standalone ignition computer.

my frind has a tt supra he converted to single turbo and it runs in the low 11's.
cool but i still dont get drag racing.

Pretty cool... Drag racing is a whole different thing from almost any other kind of driving. It does involve a lot of skill, but that skill doesn't necessarily translate into skillful driving on the road (as opposed to most other types of racing). That's just my opinion on it, though.

i like the gravel!
we had a impromptu rally drag between a 4wd s-10 blazer w/small block 350 and rally tires against a group n wrx and it was split at one win each. pretty funny after a day of rallyx clumps of grass and dirt flying everywhere!

Ooh, an S-10 with a 350 in it? Pretty cool.

greg donovan · Post by **greg donovan** » Wed Oct 08, 2003 4:22 am

hate to hijack my own thread but...

the s-10 now has a 2002 style body that has been moved back a few inches to help cg w/a fuel cell and battery behind cab a 4 link rear susp. setup in the works and rear mounted radiator. no box but fiberglass bedsides from corr truck. w/desert runner coilover setup. and to top it off a z-28 road racing steering box gearset. it is being prepped to open class scca pro rally spec. by a friend of mine. i have codriven for him in his p class rally truck. this new project is a freaking gokart. same power to weight as a wrx and same wheelbase and track. here is a link to a pic.

http://tinyurl.com/q4cj

it is a link to specialstage.com forums part of the best rally resource in N.A.
s you can see it is a work in progress hopfully to be completed by lake superior pro rally at the end of the month

btw the guys daily driver is a 93 legacy turbo.

greg

vrg3 · Post by **vrg3** » Wed Oct 08, 2003 4:33 am

That's pretty sweet!

I thought of another possible way you could select base ignition timing. I don't know if it's even realistic, but maybe you could modify the stock crank pulley to position the crank angle sensor nubs differently. Or somehow make that adjustable.

As far as I know the ECU ordinarily does ignition timing pretty much solely based on the crank angle sensor, and uses the cam angle sensor just to identify which cylinder is firing.

greg donovan · Post by **greg donovan** » Wed Oct 08, 2003 4:46 am

interesting. i will have to run that by the mechanics and see what they think?

greg

vrg3 · Post by **vrg3** » Wed Oct 08, 2003 3:07 pm

Cool. You'd probably have to look closely at a stock sprocket to see what to do.

Basically there are six little nubs on it. One for 97 degrees BTDC, one for 65 degrees BTDC, and one for 10 degrees BTDC, and then the same three duplicated on the other side.

So if you moved all of them a little, you could make it think the crankshaft was always a little ahead or behind of where it really is.

You just have to be sure to keep all the spacings the same or the ECU will get confused and/or angry, to personify it. :) And I'm sure if you went too far, it would notice that the cam angle sensor signal seems to not jive.

entirelyturbo · Post by **entirelyturbo** » Wed Oct 08, 2003 3:46 pm

As for the CR issue, I think the EJ22T thread stickied in this forum states that DOHC EJ25 heads with stock headgaskets lowered the CR to a 7.5:1...

EJ22 heads on an EJ25 would increase the CR enough that you would probably have to use 91 octane or higher...

Post by **Legacy777** » Thu Oct 09, 2003 2:19 am

yeah.....the subie dealer should have the old style select monitors. should is the key word. I've watched timing, and it's all over the board. It would be a lot more beneficial with a logging device that could correlate engine rpm, load with timing, and then compare that over time to see trending of the learning ability.

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N/A power

N/A power