EFI, ITBs and...MSI - doable?

[skipgs911]

I have not been on Pelican for a very long time, so my apologies that I am behind the times on EFI stuff. Some searches here and elsewhere haven't specifically answered my question, so I am looking to the gurus.

Bottom line question: what are the options for idle control if using MSI with ITBs (on a 3.0 SC-type engine)? Is this even possible? I am looking potentially at an ITB kit like the guy here uses:

https://www.impactbumpers.com/forum/index.php?/topic/30976-phils-cis-to-efi/

...and have access to a cheap MSI setup, and am on a tight budget. Thanks

[tirwin]

Yes, it’s possible. BUT, the 3.0 is not the best starting point. Why? The pistons are domed for CIS. You’ll probably want to change the cams. You’ll need to think about what exhaust. So the slippery slope costs add up in a hurry. Of course, you can ignore that stuff or possibly do it in stages. My problem is if I waited to do a rebuild I’d probably make it a 3.2SS with twin plug and then there would be extra costs.

If you needed a rebuild now, it would be a good time to make some of those decisions.

Otherwise a 3.2 or 3.6 would be a better starting point from a cost standpoint.

[skipgs911]

Originally Posted by tirwin

Yes, it’s possible. BUT, the 3.0 is not the best starting point. Why? The pistons are domed for CIS. You’ll probably want to change the cams. You’ll need to think about what exhaust. So the slippery slope costs add up in a hurry. Of course, you can ignore that stuff or possibly do it in stages. My problem is if I waited to do a rebuild I’d probably make it a 3.2SS with twin plug and then there would be extra costs.

If you needed a rebuild now, it would be a good time to make some of those decisions.

Otherwise a 3.2 or 3.6 would be a better starting point from a cost standpoint.

All of that sure would be nice! Unfortunately, yes, ignoring major upgrades and just getting this 3.0 running with ITBs and the engine management on hand is what my budget allows. Internal work or buying other engine types is definitely not in the cards for the foreseeable future. Thanks

[tirwin]

You’ll get different opinions on whether the 3.0 pistons are ok for non-CIS. I asked a reputable engine builder once about converting a 3.0 to EFI and he said absolutely not. Other people have clearly done it. YMMV

There are several reputable & knowledgeable guys here. Maybe they will chime in. You might get better response in the engine rebuilding forum.

[skipgs911]

Originally Posted by tirwin

You’ll get different opinions on whether the 3.0 pistons are ok for non-CIS. I asked a reputable engine builder once about converting a 3.0 to EFI and he said absolutely not. Other people have clearly done it. YMMV

There are several reputable & knowledgeable guys here. Maybe they will chime in. You might get better response in the engine rebuilding forum.

Thanks - using the 3.0 is really a non-issue to me at this point. I see a lot of folks who have. I understand that performance will not be maximized without internal upgrades.

My question is, is anyone controlling idle with ITBs and MSI (and ideally, on a formally CIS engine)? If so, how? Thanks

[David Inc.]

What's the issue with the domed pistons?

[jpnovak]

First, The 3.0 will respond to EFI without any issues. The 3.2 has the same dome shape so comments about piston shape exclusivity is absolutely not correct. Same if you want to bring cams into the equation. 3.0 and 3.2 have same cam specs.

Is the system optimal? Probably not but they run quite well on EFI. Certainly better than most CIS systems. I don't that @skipgs911 is looking to fully maximize output.

Having converted several 3.0 engines from CIS to EFI (including modified CIS plenums, 3.2 plenums and ITBs) you will notice a big improvement in throttle response. ITBs will give you improved mid-range torque due to more equal intake runner length and air flow distribution compared with any common plenum.

When you say MSI are you meaning Megasquirt-1 (first generation) or Megasquirt Injection with a later ECU? There are differences where the MS1 has limitations running ignition without modifications. It can be done but you will likely have to connect some wires on the PCB. Are you capable of modifying electronics?

Idle control with ITBs is more difficult to setup. Typically an idle bypass valve is connected to a second set of bleed ports in the manifolds. Separate paths for MAP signal and idle bypass. OFten it may be easier to install the early 911 hand throttle on the parking brake cluster. This depends on your level of comfort with all things electonic and mechanical.

Now, You mention budget is an issue. It is much less expensive to use a stock 3.0 CIS manifold that has been modified to accept EFI injectors. This is the most simple method and works well. It also keeps the stock IAC valve and thermo-time switch for idle control.

[tirwin]

Originally Posted by David Inc.

What's the issue with the domed pistons?

Jamie explained it better than I did. No surprise there.

The purported issue with the domed pistons is that they don’t work well for EFI.

Personally, I’ve talked to quite a few people about the 3.0 and I’ve seen a pretty wide variety of responses. The point I was trying to make is that anyone researching this topic will get conflicting opinions, so be prepared for that. Some people say don’t do it. Obviously, there are people who have done this with good results. Like Jamie said... is it optimal? Probably not. Will it work? Sure. Like a lot of things some people are strongly opinionated.

And it depends on objectives — just ditch CIS or more HP?

You can achieve a lot with just ditching CIS. Harder when you want to chase HP gains too.

[Peter M]

Skip,
Rasant do this really great "how to" guide on installing EFI into a SC. I think you may find it interesting:

https://rasantproducts.com/content/Manuals/Rasant_Products_Engine_Management_Installation(ITB ).pdf

BTW, domed pistons don't care if they are fed by EFI, carbs or CIS! :-)

[PhillIB]

Fame at last! I am "the guy" mentioned in the first thread.
I did the entire conversion myself using Megasquirt2. No internal work done at all.
What did I end up with? A much more driveable car, great throttle response, more horsepower (about 20 extra) and awesome noise
Total cost to me was about Ł2500 but Ł700 of that was megasquirt2 and Ł360 on the manifolds.
I already had SSIs so I am running at about 215hp out of a 180hp engine.
It was a very enjoyable project and I learned a huge amount. However, the main reason I did it was to get rid of the ugly CIS and replace with modern, easily replaceable parts. All hugely worthwhile.
I've since had the engine rebuilt so need to get it back on the rollers to see if there is any improvement in power. Once I've saved up some more money I want to change the cams.

[skipgs911]

I will check on the MS1 details. Yes, I can modify components if needed.

There is no ditching of CIS in this scenario. I don't have CIS or other intake components, so I won't be adapting anything to EFI. I need to buy everything that sits on top of the engine; going with a cost-effective ITB setup is the goal.

[mikedsilva]

I dont know about MSI (or what that is) but Rama from RHD uses an idle control valve connected to a vacuum block to control idle on his ITBs..
See this youtube link.
https://www.youtube.com/watch?v=qnUK7obc0uM

Look up Racehead Engineering in Australia

[skipgs911]

Originally Posted by mikedsilva

I dont know about MSI (or what that is) but Rama from RHD uses an idle control valve connected to a vacuum block to control idle on his ITBs..
See this youtube link.
https://www.youtube.com/watch?v=qnUK7obc0uM

Look up Racehead Engineering in Australia

Thanks; I think something like that is what I was envisioning as far as the IACV circuit goes.

Now, I need to learn more about the MSI system specs. It seems like the main question is if it can run the IACV.

[al lkosmal]

One of my favorite EFI builds was to a stock 3.2, using 46mm PMO ITBs and AEM Infinity ECU (although Megasquirt will work great too) SSIs and sport muffler and this was a great engine. I was totally impressed with the throttle response, drive-ability and power. Although i've built much hotter 3.2-3.5 configurations......I was so impressed by the stock 3.2 with EFI, I'm building a 3.2 now, to that configuration.

regards,
al

[70SWT]

Subscribed - this is a timely thread for me. After putting my '80 project on the back burner for a few months due to being overwhelmed with business and personal items. I'm looking at options for induction on my EFI project. I was thinking I may go with one of these ITB systems, but have the same issue - I have the option of using MSI, but will it work.

EDIT: I see a post in my thread on my car about needing an extra wire for idle control when using the tbitz version of MSI (from the omnipresent Jamie - man, you get around when it comes to EFI threads). So it sounds like it may be possible, at least for me, to run ITBs with MSI. I need to learn more.

[PhillIB]

When you guys are writing MSI do you mean MS1 or is it something different?

[70SWT]

Originally Posted by PhillIB

When you guys are writing MSI do you mean MS1 or is it something different?

I am. I have the Bitz Racing system still in the box. See my thread on “Bubba joins the stable” near the end for pics of exactly what I have.

[PhillIB]

Look here, lots of info. Scroll to the bottom and it talks about idle valves.
Megasquirt-1 Manual Index

[PhillIB]

This is the rest.......
https://www.impactbumpers.com/forum/index.php?/topic/32160-triumph-itb-conversion/