10 replies to this topic

[subaruguru]

Something i have been thinking about doing along with my svx swap is a 2.5 hybrid with 2.2 heads a 4bbl carb and escort disti?

I was planning on doing the 4bbl carb swap like jerry (Bratsrus1) on his hatch brat but now all this talk of the franken motor has me wondering what if you did a 2.5 with sohc 2.2 heads a 4bbl carb and an escort disty it should put out a good amount of power and no harness.

Put an EA swapped EJ trans behind it no adapter plate 2wd 4wd on the fly upgraded legacy/impreza clutch and pressure plate locking tail shaft (NO VISCUS) with a lsd in the rear. you could even do a 5 lug swap mmm that would be one sexy beast im thinking something like my red sedan but without the 5 lug swap man its going to be bad.

I can see it now all stuffed into this lil devil

[Tycho]

That car looks just like mine (cept for the hood ... and I have the checkered seats/seat belts ... and I have SVX headlights swapped into mine).

Don't forget an OBX Helical diff in that EJ bellhousing'd transaxle.

You could go D/R with the locking tailshaft with an '85 or '86 Turbo DR trans. Only 1.2 reduction, but it'd be sweet to have 5 gears for use < 100 mph.

As for engine management, these guys have some Subaru specific systems that would probably take less time to wire and program than splicing harnesses and what not. Scroll down to "Subaru Systems."

http://www.sdsefi.com/aircraft.html

[renob123]

That car looks just like mine (cept for the hood ... and I have the checkered seats/seat belts ... and I have SVX headlights swapped into mine).

Don't forget an OBX Helical diff in that EJ bellhousing'd transaxle.

You could go D/R with the locking tailshaft with an '85 or '86 Turbo DR trans. Only 1.2 reduction, but it'd be sweet to have 5 gears for use < 100 mph.

As for engine management, these guys have some Subaru specific systems that would probably take less time to wire and program than splicing harnesses and what not. Scroll down to "Subaru Systems."

http://www.sdsefi.com/aircraft.html

I'm not considering this a threadjack because it has to do with Frankenmotors and transmissions and such:)

How have you liked the OBX front diff? That's the plan for my Frankenmotored Brat.

Jacob

[GeneralDisorder]

A carbed setup would not have knock control (unless you added it with one of the spendy MSD setup's) - which would be bad for a high-comp. engine.

GD

[Tycho]

I haven't installed my OBX yet. Got it ripped apart and am going to wire wheel the ends of the helix gears and splines to de-burr them a bit (tho honestly the quality of mine is much much higher than many pics I've seen online).

I bought one of those Belleville washer + new bolt kits ... but the OE Bellevilles were installed correctly, the bolts were all torqued properly, and none of the threads were damaged. Appears they are stepping things up.

I had (dad drives it now) a Quaife brand helical in my Saturn SL2 for 70,000 miles (in addition to running an open diff for 25k miles and a Phantom Grip for 25k miles). The helical was downright magical. You absolutely never noticed it was there. With the one wheel on ice one wheel on pavement scenario, it would spin the wheel on ice, but you would still accelerate. The transition of torque from one wheel to the other was very smooth resulting in no jerkiness or torque steer whatsoever. After a while I just got used to having really really good traction in a FWD car and actually started believing that was a decent drivetrain again. Then I'd drive a rental car or a friend's car and wonder how on earth anyone could get anywhere in such a rig (with an open diff). I had to replace the input shaft seal 65,000 miles into the life of the Quaife, so I got a chance to see how it was holding up. Zero wear, no metal in the trans fluid (or on the magnet). Lot of those miles were with a high comp 11.5:1 CR quad throttle body engine that was making 155 HP to the wheels and spinning to 7500 RPM putting power through a 4 puck ceramic solid hub clutch.

It would be a perfect match to a high HP engine in a light car (even with 4wd/awd). In a PT4wd trans, it'd be even better as you could pop the thing into 2wd for mileage and have enough traction to leave it there in light snow/dirt roads. I'd also wager that increased front axle traction would significantly reduce stress on the rear driveline ... to say nothing of embarrassing cars like WRXs with their visco rear, visco center, and open front.

Edited by Tycho, 05 January 2011 - 03:40 PM.

[renob123]

I haven't installed my OBX yet. Got it ripped apart and am going to wire wheel the ends of the helix gears and splines to de-burr them a bit (tho honestly the quality of mine is much much higher than many pics I've seen online).

I bought one of those Belleville washer + new bolt kits ... but the OE Bellevilles were installed correctly, the bolts were all torqued properly, and none of the threads were damaged. Appears they are stepping things up.

I had (dad drives it now) a Quaife brand helical in my Saturn SL2 (in addition to running an open diff for 25k miles and a Phantom Grip for 25k miles). The helical was downright magical. You absolutely never noticed it was there. With the one wheel on ice one wheel on pavement scenario, it would spin the wheel on ice, but you would still accelerate. The transition of torque from one wheel to the other was very smooth resulting in no jerkiness or torque steer whatsoever. After a while I just got used to having really really good traction in a FWD car and actually started believing that was a decent drivetrain again. Then I'd drive a rental car or a friend's car and wonder how on earth anyone could get anywhere in such a rig (with an open diff).

It would be a perfect match to a high HP engine in a light car (even with 4wd/awd). In a PT4wd trans, it'd be even better as you could pop the thing into 2wd for mileage and have enough traction to leave it there in light snow/dirt roads. I'd also wager that increased front axle traction would significantly reduce stress on the rear driveline ... to say nothing of embarrassing cars like WRXs with their visco rear, visco center, and open front.

I have the Bellevilles and bolts as well. How do you plan to handle the different spline counts between the diff and the axles of an old Subaru?

Jacob

[subaruguru]

why would the knock sensor matter on the hicomp engine and not a standard 2.2 with a 4bbl carb setup? i thought the knock sensor just told the computer if the ignition timing was off? i could be compleatly wrong but i think it would still be cool to try.

Thanks Rob

[GeneralDisorder]

The knock sensor detects "knock" (cylinder detonation) and retards the timing till it goes away. Without that you will have no choice but to set the timing at a very low initial advance with a high-compression engine - thus robbing power. You can do it but it's not ideal and you will lose performance through a large portion of the power band over a knock control ignition system that can advance and retard the timing in repsponse to detonation.

GD

[Tycho]

If you have a programmable ignition system, you can dial out knock by noting at what RPM/load ranges it happens in and backing off timing at those points. Once you have a knock free map, you can chuck the sensor (or stop listening if you're doing it audibly, which can work just fine if you know what you're listening for and your exhaust isn't too loud). Just have to make sure you continue to use fuel of at least the same quality from then on.

The technique goes something like:

Start with a base timing map that follows the distributor curve (for the dizzy you're replacing).
Dial in your fuel maps.
Do WOT (full load) pulls and increase timing until you start to get audible knock.
As you get knock at an RPM point, reduce timing at that point a couple degrees and lock those values in.
Eventually you'll have a WOT (full load) timing map just below the knock threshold for the entire RPM range.
Now, at lower loads, you'll have the low advance that GD spoke of.
Any decent aftermarket ign system has a load based timing map (digital vac advance).
Just keep tweaking advance at lower loads (higher vac) until you notice knock or a decrease in power ... then back it off a couple degrees.

Now you have a knock free ignition map with no holes for all RPM and load points (X and Y dimensions of the map). You no longer need dynamic knock control unless you change something on the engine (cam, exhaust, whatever) or use lower octane fuel and/or hotter plugs.

[GeneralDisorder]

That's all well and good but does not apply to a carb setup - also removing the knock sensor after tuning would be a bad idea simply because if something should fail (an injector going lean, etc) then the system will not have the ability to retard the timing to compensate - there is also the issue of summer vs. winter fuel formulations, altitude, etc - you cannot forsee all possible running conditions or failure modes so leaving it as a fail-safe is always wise.

GD

[subaruguru]

well alright thanks for that info still think i might try it sometime...

thanks Rob.