3.2 Build EFI N42 / MN47

[madkaw]

Did more work in the ITBS . I’m mocking stuff for test runs to see what might work and what might not . Goal is a decent MAP signal up to 30% throttle and be able to run brake booster and PCV . I thought the PVC would work for the PCV - lol. Just all temporary fun. The base plate will be trimmed down to about 6” . 
Running 1/4” vacuum lines to this 1” log . It might be a bit big but I want it to do a lot

Final iteration might be 2 vacuum logs . 
Maybe ready to fire in a week or so 

[madkaw]

New exhaust for the 3.2 ! Serious drone issues from failing resonators made me go to a single thru the resonator . This resonator has a J pipe to help with the HZ 110 I had at 2200 rpm . With my tall OD this was an issue.

I went with Borlas out back as big as I can fit so in the end I’m hoping for a quieter exhaust and less drone . 

 

Edited April 3 by madkaw

[madkaw]

ITBS are bolted down after doing some fitting of the Maxima Diesel intake . 
Still waiting on the welder to finish up my collector pipe so I can’t start it yet . Also need to finalize location of vacuum log that will be inside my CAI - whenever it gets done at the welder . I wish I could TIG worth a shit and my life would be easier - lol.

Still most of the back breaking work of bolting this down and plumbing should be good to go . 

[madkaw]

Good news is my exhaust collector is ready for pick up ! Bolt this thing up and ready to fire . Reached out to Chickenman- Richard Boyk - who said he’s done tuning with ITBS before has set me up a base tune . Can say enough how helpful this is since Alpha N is all new to me . 

[madkaw]

Latest version of mock up for test flight . 
It started up easy and just idled nicely - I was in shock - lol. 
MAP readings was around 65kpa at idle which isn’t much different than the plenum idled at . Reading was jumpy so I talked with Richard and dropped the vacuum like size from .250 to .125 - which should help smooth out the reading . 
Big cam and all it just idled and blipped ! 
Wont have the my CAI done for a minute so I’m going to run open stacks until my foamies come in . I won’t run it long like that but to get a base tune down . 
Murdered out my vacuum log so it would be so obtrusive . 
 

[madkaw]

Reducing vacuum line size seems to have helped the MAP reading. Looks like I might even get 60kpa at idle too! 

First drive was interesting for sure. Almost stalled pulling out in traffic and rich and lean mixtures all over the table-lol. The autotune was trying to correct but some of my settings were off. I didnt stay out long because it was Little 5 in Bloomington and too many crazy kids out . Monday when everyone is at work Ill do some more tuning, 

Idle seemed to increase as the engine got hotter. No heat shield yet so that is an issue  

[DuffyMahoney]

15 hours ago, madkaw said:

Reducing vacuum line size seems to have helped the MAP reading. Looks like I might even get 60kpa at idle too! 

First drive was interesting for sure. Almost stalled pulling out in traffic and rich and lean mixtures all over the table-lol. The autotune was trying to correct but some of my settings were off. I didnt stay out long because it was Little 5 in Bloomington and too many crazy kids out . Monday when everyone is at work Ill do some more tuning, 

Idle seemed to increase as the engine got hotter. No heat shield yet so that is an issue  

Idle increase while hot is the same issue most of us ITB guys are dealing with, I hope a heat shield fixes it.  

[madkaw]

Drove around yesterday with heat shield on .  The tune is pretty rough and and sometimes the car wanted to die from starvation -scary . 
I used timing to lower idle after reading about a trick to deal with hit idle . Might have to call on Richard to help me remotely . Lots of rain right now so driving time is scarce . 

[madkaw]

Ordered some cheaply sponge filters while I wait for my CAI box to get finished . Made a smaller vacuum log -3/4” PVC pipe . 
Despite having one of my widebands flaking on me I was able to drive around well enough that I wasn’t scared of dying on the road anywhere . Not much help out there for guys running MS and ITBS. Seems most Haltech or others . I’ve also got different perspectives on how to load certain tables . I have Yanni saying that all the tables can be run off of TPS and Richard that says running timing off of MAP is best . Presently I am going to try and run it all TPS . I can only hope the FAJS version of a TPS is accurate and reliable . I might eventually go with a contactless style from EFI hardware . 
For now I haven’t gotten past 38% TPS on my tuning  so I’m not stressing my TPS to hard that’s for sure . Honestly - I didn’t think it would run even this good this early in the tune . I am trying to be patient with throttle input since I do hit big lean spots . I am also learning how to use Megalog Viewer at the same time that has a VE analyzer which is pretty damn cool . 

Edited May 9 by madkaw

[Derek]

I feel like Megasquirt and ITBs on my car is like a game of whack a mole. Getting it to work under hard pulls isn't an issue but getting it to be tame in normal driving scenarios can be daunting. 

[madkaw]

9 hours ago, Derek said:

I feel like Megasquirt and ITBs on my car is like a game of whack a mole. Getting it to work under hard pulls isn't an issue but getting it to be tame in normal driving scenarios can be daunting. 

What’s funny is that just cruising around is all I’ve got done as far as a tune . I’ve got a Z friend Yanni Maltabes that use to post here I believe . He swears he can help me tune purely alpha N and it will as good as MAP . 
I’ve also come to the realization  that I can no longer be lazy about learning Megalog viewer and analyzer . Maybe also got lucky that these FAJS ITBS seemed to be very solid right out the box . Solid idle and good enough to drive and tune . I also know my engine very well so I will know when I have it right . Who knows if I will stay the course forever or try my diesel intake later . 
 

Are you running the ITB or Alpha N ? 
Yanni tells me he can run every table strictly from TPS - which seems daunting . When I started reading about scatter plots and needing data logs from MAP runs to utilize ITB mode in MS is when I decided to go strictly TPS . I will have MAP in the background 

[Derek]

13 hours ago, madkaw said:

Are you running the ITB or Alpha N ? 

My tuner has me setup with speed density and a separate idle table. All in all it does fine but the reality is until I build my stroker I have way too much induction for the displacement. 

[jonbill]

I run pure Alpha-N on my engine with Speeduino. 3.2 stroker with a diesel block. FAJS 45 ITBs. I have it working very well everywhere.

Idle  is managed with Speeduino's ignition advance idle control. It starts on the key from cold and hot without touching the throttle and idles at 1100 throughout.

Its in bits at the moment, but when it goes back together it'll have 50mm Sherryberg ITBs.

[madkaw]

On 5/14/2025 at 6:20 AM, Derek said:

My tuner has me setup with speed density and a separate idle table. All in all it does fine but the reality is until I build my stroker I have way too much induction for the displacement. 

All I’ve read in my adventure is that there is no way to run ITBS with speed density correctly . After tuning with MAP for years I see why you have to run Alpha . ITBS put you at atmosphere pressure so quickly with no plenum . It’s a challenge to rethink how the tables work with ITBS for sure . 

[madkaw]

15 hours ago, jonbill said:

I run pure Alpha-N on my engine with Speeduino. 3.2 stroker with a diesel block. FAJS 45 ITBs. I have it working very well everywhere.

Idle  is managed with Speeduino's ignition advance idle control. It starts on the key from cold and hot without touching the throttle and idles at 1100 throughout.

Its in bits at the moment, but when it goes back together it'll have 50mm Sherryberg ITBs.

Are you running Tunerstudio? Either way would you share some screen shots of your tables ? Curious how efficient you have the motor running as far as power vs mpg ?

45’s to small or looking for more power ? I think my small port head will like the smaller ITBS . 
You have a thread I can read up on ?

thanks 

[Derek]

2 hours ago, madkaw said:

All I’ve read in my adventure is that there is no way to run ITBS with speed density correctly

I agree and I brought that up with him. He had a ton of ITB experience with Megasquirt so I deferred to his expertise. The only complaint I have is when I'm low speed lugging through my neighborhood it really starts lugging. Other than that it runs great as far as I'm concerned. I tend to have my foot in it most of the time though. DOHC and ITBs under load makes for some sweet music  

[jonbill]

7 hours ago, madkaw said:

Are you running Tunerstudio? Either way would you share some screen shots of your tables ? Curious how efficient you have the motor running as far as power vs mpg ?

45’s to small or looking for more power ? I think my small port head will like the smaller ITBS . 
You have a thread I can read up on ?

thanks 

yes, Speeduino uses Tunerstudio too - I'll share some screenshots and the tune.

I'm switching to 50s because this engine doesn't rev out like my previous 2.9 did - it would zip round past 8000 but this one is more powerful below 6000 but isn't so keen to rev past 7000 at all. It might just be the longer stroke, but it could be the 45s are too small so I have to find out. 

on the motorway it does about 35 mpg (UK gallons, so prob 30mpg US). and I'm confident it's well more than 300bhp  (but never proved it, because that costs money :))

 

VE table:

 

Spark table:

AFR table 

 

I only use closed loop o2 control at low throttle openings. Above that, it does hit the target AFRs quite well, after years of logging and histogramming with MLV.

 

 

CurrentTune.msq

[jonbill]

the most valuable tuning tool for me has been this MLV histogram - I can drive around all day logging, and then load this and in one view I can see how close the tune is to where I want it to be. 

[madkaw]

Thanks so much !!

I will study these . I’ll download your tune and look at it . Sounds like our engines are very similar . 
what head and port size ? 

[jonbill]

It's a welded  p90a. I think the ports are 38mm. I think they must be as big as they can be since the head bolt holes broke through when we drilled them for m12 bolts.