ITB bug

[Pehlen]

I've decided that this winter's project will be installing ITBs on my perfectly good 1988 Carrera, along with an ECU upgrade.

The reasoning is simply aesthetics. The look and sound of the ITB's is simply outstanding. I've convinced myself that it's a good idea, too, should I decide to go more aggressive with cams of something like that in the future

After quite a bit of research on this board and elsewhere, I've decided to take a path right between DIY and a turnkey kit (actually, time will tell, but it may be closer to a turn key kit that right down the middle).

I've selected Al's (X-Faktory) Triumph ITB kit and Andrew's (Rasant) AEM kit. That's all been ordered and I am (impatiently) waiting for a great Christmas present.

In the mean time, I've begun the tear down and will post, retro, some of that process. I've learned all I know from this board, so hopefully this will give a little back.

As background, I'm starting with my lightly modified 1988 Carrera, which became mine just over 6 years ago. I've done something to it every year, gradually increasing in complexity and the risk of me impairing what has turned into a great investment...

1) Rebuilt the brakes all the way around
2) Installed a Fabspeed euro cat bypass and a modified stock muffler with 1 in, 2 out, debaffled (plus Steve Wong chip)
3) Full suspension refresh with poly bronze, sport bilsteins, turbo tie rods, sway away adjustable spring plates, too many small parts to list - WOW, this had great seat-of-the-pants value (lowered the car too, actually too much but I love it)


Here are some glamour shots:



More soon

[Joe Bob]

He has a good system and it has demonstrated that it works well. What did it set you back?

[dfhtrhjn]

I was also considering ITBs, mostly because the CIS on my 2.7 won't last forever and has abysmal throttle response.

I noticed x-faktory has a complete kit, what's the advantage to the Rasant engine management?

[evan9eleven]

I'm dreaming of the same setup, looking forward to the updates!

Al is fantastic at providing info, no brainer going with one of his packages.

[tirwin]

You can add me to the list of people contemplating the same thing. Can't wait to hear how it turns out!

[Maxhouse97]

I will do this at some point, ITBs are amazing!

[Techno Duck]

Looking forward to your feedback on this setup. If I didn't have to deal with emissions here in CA I would do the same. I am almost tempted to swap between the ITB's and the stock motronic setup every 2-years just to pass smog.

[Taxi!]

Al's the man. Subscribed.

[Pehlen]

He has a good system and it has demonstrated that it works well. What did it set you back?

List price, right around 6 grand

I noticed x-faktory has a complete kit, what's the advantage to the Rasant engine management?

I liked the features of the AEM Infinity better than the Megasquirt and I was really sold on the AEM Engine Position Module that adapts the distributor to be an accurate cam and crank shaft sensor. Add to that the rest of the kit from Rasant - like the coil on plug components and the custom harness - and it just seemed like the perfect match for what Al is doing - and he has done a few of jobs with the Rasant kit as well.

[Pehlen]

I've already disassembled the everything from the airbox down through the intake. I did this all with the engine in situ. I considered dropping it, but there we not much benefit, from my perspective. While contemplating alternatives, I would have had to drop it if I had got the Clewett route (which I still think is a fine direction to go, just not the one I chose).

One advantage I had in this decision was that I had already backdated the heater and removed the AC and it's mounting mess (hoses are still in, for now).



This process was quite easy - my notes say it took me just over 3 hours, and I was taking my time, learning and inspecting things as I went. Part of that 3 hours was invested in removing the fan, housing and alternator, since I wanted to dress it up a bit as part of the process.



As you'll see below, I found that my fan housing's small crack had grown (I know I over tightened the belt for a bit). it probably would have been fine for a while, but why chance it. I ordered a new magnesium casting from CarPoint. So far, that has worked out well.



I also ordered some Dow 19 magnesium treatment of the fan. My hope was to achieve the bronze color of treated magnesium, but that did not work out well. The worst case of this approach was that the Dow 19 treatment is a paint prep for magnesium, so I just masked the fan and painted it satin black.




Getting to all of the bolts, wires and hoses was a bit of a challenge, but nothing was overly difficult. The only really odd thing is that there is a mounting bracket for the fuel line, one of the wiring harnesses and another hose (can't remember which one) at the very front of the engine and the screw that holds it all in place happens to be a smallish hex head screw. There are pretty much no other hex head screws in the engine bay (save for the barrel nuts on the intake manifold), so it took me a while of get a good view of what it was!





Once everything was out, I commenced to cleaning the fan shroud and the rest of the top of the motor. This is another job that could have been done much more completely and much more easily had I dropped the motor. For now, it's an OK cleanup and I'll save the detailing for another winter.




I also commenced to fabricating an aluminum mounting platform, coming off the top of the breather, for the vacuum manifold I bought and the oil tank breather I bought. For now, I've tapped and bolted the aluminum platform together; it may get welded together before I'm done - not sure. Also, I've modified the oil tank breather with a drain tube and ball valve along with the 1" hose barb for the stock hose from the oil tank.



This is as far as I've gotten so far - about a week's worth of work most evenings after work.

[captain hook]

Sounds cool. I also have x factory full kit with crank fire ignition. I haven't got around to installing it yet. But a cool winter project.

[Tippy]

You did this right by taking 2 proven kits.

Rasants pricing isn't too bad. Making a kit like this is no small feat.

I'm on my 2nd go'round of ITB fabrication using GSXR 750's and I think I'm throwing in the towel again.

Too much fab work and machining.

[al lkosmal]

Originally Posted by Pehlen

List price, right around 6 grand



I liked the features of the AEM Infinity better than the Megasquirt and I was really sold on the AEM Engine Position Module that adapts the distributor to be an accurate cam and crank shaft sensor. Add to that the rest of the kit from Rasant - like the coil on plug components and the custom harness - and it just seemed like the perfect match for what Al is doing - and he has done a few of jobs with the Rasant kit as well.

Phil...thanks for starting the thread.............this will be a great build and you seem to be diving right in and are very capable. I appreciate that approach.

I want to thank all of you for the kind words regarding my systems and work....much appreciated........

.........just some general info for those asking questions about the system choices........It's not generally known, but I offer quite a few system configurations......based on price/feature/performance..... employing ECUs ranging from Megasquirt thru AEM Infinity (currently using Rasant. Andrew makes such a nice, high quality harness) but I have also used others, as required....the same goes for the t'bodies/intake system....everything from my own Speed Triple package thru most other off the shelf ITBs on the market. I.E. I listen to the end user...gain an understanding of the needs/wants requirements and then offer several, integrated system options to choose from..........Phil chose a really good system option that will transform his engine............stay tuned.

regards,
al

PS: I definitely don't want to derail Phil's build thread.........so if you have questions for me, please PM me or contact me thru my website.....and in the meantime...i'll be getting Phil's system together and ready for shipping.................nice Christmas present............

[Ferrino]

Slight bias here, since I am slowly putting together a DIY ITB system for my 3.2, but ITBs are, in my opinion, the epitome of a "restomod". Recapture the visual and aural delight of the early 911s, coupled with a modern, mappable and more efficient fueling/ignition system. For me, there is no fart cannon which can reproduce the "hairs on end" feeling you get when you wind up a carbed/ITB'd motor.

[Clay.0]

In for the build

You'll definitely enjoy your ITB setup with Al and Andrew's kits. Both great products.

[Joe Bob]

Besides the obvious, throttle response, aesthetics, etc...how many horses do you expect?

[Pehlen]

@Joe Bob - from what I've read, without going to more aggressive cams, I don't expect much HP gain. I think I'll see something at higher RPM, but perhaps a slight drop in mid RPM range. I'll get it on a dyno for final tuning, so we'll see then. I'm hoping to feel some difference in throttle response. I'm open to being convinced differently on the HP front.

[Pehlen]

I think I've settled on how I'll mount the oil breather catch can. I'm going to find a shorter air filter for it an install an elbow in the bottom for a hose to fascilitate periodic draining if needed.

[al lkosmal]

the only dyno results I have were done by the Dzug guys in N.C. They did a before/after with their 3.2SS. This used 964 cams (these are pretty mild), SSIs and sport muffler and still used the stock CIS intake system.

The only change made was to replace the CIS with my EFI/ITB system.

Here's the before/after






That is approximately a 12% increase in HP and a 15% increase in TQ with no other changes except replacing the CIS with EFI/ITB.........

video


https://www.youtube.com/watch?v=pxXwaL_TdmY&feature=youtu.be

No question that the 3.2 system is different from the earlier CIS system....but it does have the single throttle body, unequal length intake runner and air/fuel meter flappajammer in the intake...............in common.

regards,
al

[Pehlen]

I've been a little tied up with work the past few days, but had an opportunity to progress this project a bit this evening.

The Motronic DME has been removed, along with the wiring harness - well, at least the harness is out of the engine compartment. I thought this was going to be more difficult that it ended up being.

Taking a page out of a similar project I had read on this forum, from quite a few years ago, I plan on leveraging the connections available at the DME relay for power, ignition switched power and a power lead to the fused fuel pump line. More pictures on that later.

The engine compartment is cleaning up nicely, and beginning to look much less cluttered. I did a few other uninstalls (like the rear wiper), in order to remove stuff I don't use and would just add to the clutter of the engine if not needed.

Al says the ECU and wiring harness may ship this week - so it won't be long before the tear down stops and the install begins!



It's hard to see in this, but in order to reuse the wiring that went to the DME relay, I need to disentangle that part of the wiring from the main DME wiring, along with the wiring that runs from the DME to the front of the car.


I'll be able to mount the AEM ECU on the driver side rear passenger footwell, and reuse the factory cutout for the Motronic wiring harness for the Rasant wiring harness.


A much less cluttered engine compartment


And a perfectly good Motronic ECU that will be going up for sale shortly.