E30 #2: 1990 Delphin: RHD ITB M20

[Digitalwave]

Came across your thread when searching for information about the RHD ITB kit. I wish the pics in here were still working! It looks like a great source of information, even though he has since fixed a lot of earlier issues with his kits.

Question: how come you run your Megasquirt on Alpha N instead of Speed Density?

[318aye]

Came across your thread when searching for information about the RHD ITB kit. I wish the pics in here were still working! It looks like a great source of information, even though he has since fixed a lot of earlier issues with his kits.

Question: how come you run your Megasquirt on Alpha N instead of Speed Density?

Still working on the pictures, sorry! It's coming, I promise.

Lots of stuff has changed on the car, I'll try and get up to date shortly.

On the ECU method: 50% lazy, 50% "It ain't broke...". I've had bad luck with vacuum accumulators in the past, and tuning difficulties even once I established MAP signal with good resolution. Alpha N has been fine for the type and amount of driving that I do.

I'll probably look into using more of the MAP utilizing features eventually, as low load drivability could be better. For now I just enjoy driving it :P.

If you have questions or need help, pm away!

[spec-al]

Still working on the pictures, sorry! It's coming, I promise.

Lots of stuff has changed on the car, I'll try and get up to date shortly.

On the ECU method: 50% lazy, 50% "It ain't broke...". I've had bad luck with vacuum accumulators in the past, and tuning difficulties even once I established MAP signal with good resolution. Alpha N has been fine for the type and amount of driving that I do.

I'll probably look into using more of the MAP utilizing features eventually, as low load drivability could be better. For now I just enjoy driving it :P.

If you have questions or need help, pm away!

Any recommendations to those of us thinking about pulling the trigger on a ITB kit? Worth it? PITA?

[mr.]

^^^
Stroker & ITBs would be my dream setup. Only thing I seem to notice is the constant need for tuning and readjusting of ITBs. As a spirited daily/weekend driver this would be my only concern. I don't care much for big HP numbers. Something close to 200 would make me happy. I just love the M20 too much.

[Digitalwave]

On the ECU method: 50% lazy, 50% "It ain't broke...". I've had bad luck with vacuum accumulators in the past, and tuning difficulties even once I established MAP signal with good resolution. Alpha N has been fine for the type and amount of driving that I do.

I'll probably look into using more of the MAP utilizing features eventually, as low load drivability could be better. For now I just enjoy driving it :P.

If you have questions or need help, pm away!

Any ideas of why you had trouble with speed density even when you had a good MAP signal?

Since the RHD kit comes with a vacuum distribution block, it seems like it would be easy to use the MAP sensor tapped off that block.

[digger]

Any ideas of why you had trouble with speed density even when you had a good MAP signal?

Since the RHD kit comes with a vacuum distribution block, it seems like it would be easy to use the MAP sensor tapped off that block.

the map sensor is more stable with a vacuum block rail but it is still not as nice as with the OE plenum. also the vacuum is less so you could be idling at 75% load especially with a hotter cam so you lose some "resolution/range"

[318aye]

Any recommendations to those of us thinking about pulling the trigger on a ITB kit? Worth it? PITA?

I have yet to see a better performing kit for the M20. Rama has updated the throttle linkage, back plate design and other features as production has gone on so things like fitment and ease of use are likely better than when I first installed. It's well made, looks awesome and works as advertised. Can't think of an NA M20 that wouldn't benefit from them, go for it!

^^^
Stroker & ITBs would be my dream setup. Only thing I seem to notice is the constant need for tuning and readjusting of ITBs. As a spirited daily/weekend driver this would be my only concern. I don't care much for big HP numbers. Something close to 200 would make me happy. I just love the M20 too much.

~230+ is my overall goal, plenty in an E30 and pretty attainable. To give some perspective, the only times I've touched the kit was to replace a faulty TPS, and maybe 2 other general "refreshes" in the past ~9000 miles where I was in there cleaning and resynced the throttles because I wanted something to do. I recently adjusted the throttle tension as I have the old style spring, but adjustments are few and far between especially if you aren't DDing.

Any ideas of why you had trouble with speed density even when you had a good MAP signal?

Since the RHD kit comes with a vacuum distribution block, it seems like it would be easy to use the MAP sensor tapped off that block.

See Digger's reply. It's the resolution loss that has hosed me in the past. The kits didnt originally ship with those IIRC.

Still working on updating the pics and getting back to present day on here.

[ForcedFirebird]

Typed out a huge response as far as MS/M1.3 tuning....got lost in the upload.
Sorry.

In basic, 230whp is easy talk with a good engine builder on a 2.8/280 cam, no sweat on a 3.0/284.

Waiting on a 3.1 Peerless-built m20 to trip the dyno with a WOT tune. Then I will really see what a 3.1 vs 2.8 vs 272 vs 284 will do in a real chassis on a real dyno with replicating results on the same dynojet machine I have been beating up for 8yr.

[Digitalwave]

Typed out a huge response as far as MS/M1.3 tuning....got lost in the upload.
Sorry.

In basic, 230whp is easy talk with a good engine builder on a 2.8/280 cam, no sweat on a 3.0/284.

Waiting on a 3.1 Peerless-built m20 to trip the dyno with a WOT tune. Then I will really see what a 3.1 vs 2.8 vs 272 vs 284 will do in a real chassis on a real dyno with replicating results on the same dynojet machine I have been beating up for 8yr.

John, you want to tune my RHD setup on a high compression, 284 cam 2.5L?

I'm think going to get my car up and running on MS2 first before installing the RHD kit. It will be easier to separate MS and ITB problems if I do them one at a time. But I would really like to see if it's possible to run speed density with the ITB's, rather than Alpha N.

[digger]

You'll want a 288 or more if you want to push past 230 with itb there isn't much downside the throttles tame the cam and power gains keep increasing (not like a standard intake where it doesn't drive as nice and you hit a wall power wise)

Alpha n works fine on the street if the ecu is half decent, you use a good tps and you get it tuned properly.

[Digitalwave]

You'll want a 288 or more if you want to push past 230.

Alpha n works fine on the street if the ecu is half decent, you use a good tps and you get it tuned properly.

It will be MS2 with an OEM E36 TPS and professionally tuned. I still believe speed density is superior to alpha N (even on, or especially on a track-only car), but my understanding of it all is basic at best. Anyways, didn't mean to highjack 318aye's thread, I'll chime back in if I have any questions with the RHD install.

[digger]

Imo it makes even more sense for alpha-n on track car

I always recommend using contactless tps with alpha-n as load you get zero issues with them as they deal with vibration, heat and noise better and basically don't wear out. A new OEM will work to but used ones can be suspect. Many OEM have moved this technology.

[Digitalwave]

Imo it makes even more sense for alpha-n on track car

I always recommend using contactless tps with alpha-n as load you get zero issues with them as they deal with vibration, heat and noise better and basically don't wear out. A new OEM will work to but used ones can be suspect. Many OEM have moved this technology.

What do you use for a contactless tps? Are there ones that are compatible with the M20 TB? Where does Rama mount the TPS by the way? I didn't see that in his instructions. Does it mount on the side of the cyl 1 or 6 tb?

Are you guys running the 40mm or 42mm TB's? Which would be recommend for a 2.5L, 10:1, 284/272 motor? I'm guessing the 40mm is still sufficient.

[digger]

On stock m20 tb you mount the sensor with an adapter but I wouldn't use alphan with a single throttle so a standard wiper one is usually ok as it's not a primary load sensor when using SD. Penny and Giles or variohm xpd make compatible sensors it's not 100% pnp as you need to trim the shaft length so the sensor doesn't hit the firewall as it's physically bigger. Tps is on number 6. 40mm is fine

[ForcedFirebird]

John, you want to tune my RHD setup on a high compression, 284 cam 2.5L?

I'm think going to get my car up and running on MS2 first before installing the RHD kit. It will be easier to separate MS and ITB problems if I do them one at a time. But I would really like to see if it's possible to run speed density with the ITB's, rather than Alpha N.

Would love to. one of my favorite parts of my job is going to dyno test/tune cars.

As far as worrying about the order of things, don't sweat it. If you are purchasing a dyno tune, I can load a tune (or send it) that will work right away, but the putting on the rollers will get the most out of it.

As far as Alpha-N vs SD, I would say do a dual tune or dual maps. The Alpha definitely is the winner when at or near WOT often, but I find funny things happen when you make adjustments, then change gears. The 3.1 has a weird spot at 45mph when cruising, but then when the VE is fixed up, the same gurgle comes back at 65mph. Problem is the VE map will have an RPM/TPS location matching in two gears. Your VE isn't going to be the same.

Now, on the other hand, SD is a nicer driver for cruising. You can lug the car along in the high gear at low speeds without dumping fuel - but - you lose a great deal of resolution. The car is going to idle at or around 80kpa. So now you only have 20kpa total to work with which isn't much, so "zooming in" from 80-100 by adjusting the left hand map values, it can work half decent.

I would suggest two tunes. One for cruising on the street, the other for when you want to go all out and don't mind keeping the engine rev-happy (track days etc).