[Paul]

The clutch on the HF is slowly but surly going out on me. Ive ben driving it super carful to keep it goin as long as possible and im thinking sometime within this month its gonna be gone.. So instead of spending 400-500 on a clutch job at some shop im thinkin of buying my friends Si motor and tranny for 600. makes more sense to pay a little bit more and get some more power.

So the questions i have are what all i need to swap an Si motor into a 89 HF

anything and everything you could think of

Thanks in advanced

Paul

 

[88DXCRX]

You could use the HF axles in the Si transmission..

But it would probably be best to get some Dx/Si etc.. hubs

 

[Paul]

is that all?? i know there has to be more.

would it be fine to run the HF axles and hubs for a while untill i can afford to upgrade?

also im pretty sure i would need the ECU for the A6. anyone have one layin around?

wiring?

 

[downest]

I just did this on stef's car. There is some minor rewiring that needs to be done... let me dig that up. Also you need the PM6 (Si) ECU. You also need a new exhaust and intake to go with the A6, stock is fine, but the HF intake is like a straw and the exhaust manifold is different. If you have emissions inspection you will also need a Si/DX cat, since the HF one is on the front of the engine under the header. Your dizzy, alternator, etc will work with the new motor, so if they come with it you'll have some spares.
If you need an Si mani let me know, I have a bunch of them kicking around.

 

[downest]

Found it.

Next is the fast idle control solenoid valve (F-I-C-S-V), which is mounted on the back of the Si intake plenum, near the EACV. it's plug uses 2 wires: black/yellow and a blue. Black/Yellow (later referred to as B/Y) is a 12V + and routes to the B/Y from the EACV plug. The Blue wire goes to pin B2 on the ECU. B2 is currently connected to the green/yellow wire from the "shift up light" in the guage cluster. The plug for this wire contains a green/orange and a yel/red wire. It is under the driver's side of the dash, connected alongside the fusebox with a white plug. Cut the green/yellow wire from the plug on the harness and splice in the blue wire from the Fast idle control solenoid valve, with the new wire going toward the ECU. Don't connect the F-I-C-S-V wire to the plug under the dash, or weird stuff will happen with your shift light! The "shift up" light is now disconnected (YAAAAAA!!!) and the green/yellow wire on the plug under the dash now hangs bare. F-I-C-S-V wiring is now complete.

I would swap to Si brakes, but the HF axles/hubs will work just fine with the Si tranny. I did the Si swap on stefanos car because the axle and the passenger side hub weren't coming apart, and we had them laying around anyway...

 

[Paul]

The A6 comes with all parts on it. It has some sort of aftermarket header/downpipe so none of that should be a problem.

I also have a full catback that ive ben waiting to throw on the car since the HF manifold doesnt match up.

Will my HF wiring harness be a simple plug and play onto the A6 with the exception of the FICSV you mentioned? Will the HF harness plug into the PM6?

Also the 88-91 SI hatches do come with the D16A6 right?

Thanks for all the help so far!

 

[downest]

Yes, yes, yes... and you can eliminate the EGR setup since the A6 doesn't use it. Keep that HF manifold around...

 

[Paul]

Alright this seems pretty simple and straight forward. My mind is at ease now i thought this would be a hastle for me.

A realistic swap time..this could probably be done in an afternoon with a couple of friends?

And whats good about the HF manifold...i thought it was restrictive?

Thanks for all the help its really appreciated

 

[mattminerDOTcom]

its commonly used with a plate adapter for a cheap turbo manifold.

[email protected]

 

[therobesons]

With the price of fuel so high the demand for the HF is getting higher all the time.

You might find it a better idea to sell the HF, and get a SI.

With the Si you will get 4 wheel disk brakes, power steering, tilt wheel sun roof and more.

The clutch doctors will change the the clutch for about $200

Save the HF get Si.

IMHO

Bob

 

[downest]

That's true, but it might also be hard to find an Si. I would keep the HF motor around at least. Some people don't like the Si either. Stef specifically wanted a DX or HF to swap an Si motor into. He liked the Si for performance, but wanted a slightly lighter car, he's too tall for a sunroof (more head clearance in the non-sunroof cars), and it's a lot easier to find an HF that hasn't been beaten on, since the Si is performance oriented.

 

[toxiclows]

is that all?? i know there has to be more.

would it be fine to run the HF axles and hubs for a while untill i can afford to upgrade?

also im pretty sure i would need the ECU for the A6. anyone have one layin around?

wiring?

yeah I ran my setup just like that for quite some time. .. . .stock a6.. . . .but i pounded on that little thing till she chucked her last rod and never had a problem with the axles at all you will be fine till you can upgrade. . .

Chris

 

[Paul]

if i could sell the HF to get an SI i would but i dont think i could sell the HF for very much at all

 

[south_crx]

i went from a d15b7 to a d16a6 all the parts off of the d15 fit perfectly on the d16 but i dont realy now anything about the hf's

 

[hcrx333]

ive worked with my d15b2 dx for 2 years now and have converted it to mpfi as well as threw in an si trans. Along with other bolt ons, light flywheel, fpr, and msd.. i wouldnt trade it for an si anyday. The only thing i envy about the si is the rear discs, gotta swap the drums out soon. Its fun to see the car evolve when your starting with an hf or dx. It adds to more of an awe factor when people dont see an si decal and hear that you have a 1.5 litre engine. On top of this the dx engine has slightly higer compression, and even though the a6 cam is definately an improvement to the b2, the ports where fuel is injected through the head are angled so that its shot straight through.. whereas the si head the fuel hits off of the tunnel at an angle first, the richoccets down before being ignited.

 

[jfrolang]

the ports where fuel is injected through the head are angled so that its shot straight through.. whereas the si head the fuel hits off of the tunnel at an angle first, the richoccets down before being ignited.

Huh? The heads are the same.

 

[hcrx333]

its ported differently since it was originally meant to run on a completely different kind of fuel injection setup.

The a6 head and dx head have different codes also for the reason of them being different.

DX D15b2 5sp---------------PM8

Si D16A6 5sp--------PM3