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hey, been wanting to do this for a while and ive finally gotten myself together and am setting out to get it done, but i need some help. i plan on fitting a set of bmw itbs to my 7mge. im not very knowledgeable on ecu's or sensors, and i need to know what i can do to make this work, what are my options ecu wise (can i use the stock ecu, if not what can i use), what do i do about the afm/other sensors?
 

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Not a 7M, but I have ITB's on my RB20 240sx. For measuring air, I went with a map sensor. I drilled and tapped holes in each runner between the ITB's and the head to run vacuum lines to a vacuum block/manifold, I also used this block as a vacuum source for the brake booster with an inline check valve.

I have an AEM V2 running perfect and idling rock solid without an IACV, but i also don't have AC in the car. The tuning was done at UMS Tuning here in AZ.
 

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  1. Not a 7M, but I have ITB's on my RB20 240sx. For measuring air, I went with a map sensor. I drilled and tapped holes in each runner between the ITB's and the head to run vacuum lines to a vacuum block/manifold, I also used this block as a vacuum source for the brake booster with an inline check valve.

    I have an AEM V2 running perfect and idling rock solid without an IACV, but i also don't have AC in the car. The tuning was done at UMS Tuning here in AZ.
    im really bad when it comes to knowledge on ecu's, does it have to be specific to your car or can you get say, a universal one? to my knowledge there are no ecu's specifically made for the ge
 

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I don't know much about the MKIII at all. In my case I got an AEM V2 that physically plugged into my harness, as opposed to using a patch harness or being wired from scratch. Either way there will almost certainly be wiring involved. Your ecu choice will depend largely on what your tuner is comfortable with.

Honestly, the wiring/ecu will probably be the least of your worries. You have to figure out how to attach the ITB's to the head, then you will need a way to synchronize them. You will also need to figure out how to get a TPS signal, throttle cable routing, vacuum, etc...

It's a lot of trial and error, time, and money. In my case I learned a lot and it's fun to have a unique setup, but it was absolutely not worth the cost and complexity. There's a reason most people don't go with ITB's ;)
 

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I don't know much about the MKIII at all. In my case I got an AEM V2 that physically plugged into my harness, as opposed to using a patch harness or being wired from scratch. Either way there will almost certainly be wiring involved. Your ecu choice will depend largely on what your tuner is comfortable with.

Honestly, the wiring/ecu will probably be the least of your worries. You have to figure out how to attach the ITB's to the head, then you will need a way to synchronize them. You will also need to figure out how to get a TPS signal, throttle cable routing, vacuum, etc...

It's a lot of trial and error, time, and money. In my case I learned a lot and it's fun to have a unique setup, but it was absolutely not worth the cost and complexity. There's a reason most people don't go with ITB's ;)
again im not exactly sure how ecus work but im thinking i might be able to replace the signal from the afm with the signal from a tps and run that on my itbs and call that part good? theyre both potentiometers so if i could find one with the same voltage output?
 

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You need both the TPS, and a MAP system.
Due to the rotation direction difference, you need a TPS that turns in the opposite direction, than the one on the 7M throttle, I am using one from another Toyota, have the p/n saved around here somewhere.

Do you have the M46 ITBs ?

A MAP-ECU along with your factory ECU will handle the fuel requirements, as an APEX-i Super-AFC for tuning ease.
But I've decided I needed more control of engine management, due the the high rpm, and output goals, so have picked up an Infinity-6

I tossed the BMW oem throttle linkage, as it's cheap shit.
Added needle bearings to the throttles where the stock shaft passes through them, and used custom throttle arms, links, and a stainless steel shaft.
Some of it can be seen here: 7M itbs.
 

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OP- if 6 pack didn't make this work - no offense - your most likely not in a position to make this happen

who knows, maybe you did a career at nasa and now work at gas monkey (and own rouch racing) and can make this happen. anything is possible.

for the uninitiated - 6pak is a master level machinist / fabricator / mechanic...he walked away from this pipe dream of ITB. don't listen to me. look at the head in the thread he linked and shit he posts (like twin charged 7m!), it speaks for itself....

everyone (no offense mr na cressida that maybe can beat my supra ;) wink wink i want a 1/4 time slip w the new trans setup) should honestly walk the hell away from a na powered 3L car that tips the scales @ two tuns.

it would possibly be easier to swap the bmw motor in the car to achieve this itb supra dream. whatever that dream is. hell, 6 side draft mikuni's would be easier.


if you want more performance, the car needs a turbo. period. this. is. what. it. needs.
 

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Oh, it will work, just not had the time.
It may seem to be a dead idea, but not.
Had many other projects along the way, and things keep being changed on my 4-door taxi.
The last time it was on the scales, it weighed 3400, with full interior, a half tank, and me in it, but still lighter than my favorite victims, mustangs & such.

Already did 4 Vance & Hines drag bike Mikuni carbs on my late Datsun pick-up, which was killed a couple of months ago by some idiot bitch coming out of a parking lot, and T-boning me.
Had put several years into that. Was fun, especially out running good old boys in their big ass pickem up trucks on the freeway.
250743


Yes, if you want max power, it takes forced induction.

And first guy I want to look up is the one with the MkIV, NA with ITBs. :)
I don't think he will be a problem...
 

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It's a lot of trial and error, time, and money. In my case I learned a lot and it's fun to have a unique setup, but it was absolutely not worth the cost and complexity. There's a reason most people don't go with ITB's ;)
I've entertained the idea long enough to know that I simply will NOT spend what it would take, between time and money, to make it happen on any of our cars. Shame, really, as Miatas sound damn good with ITB's. So do 1UZ's (I can only imagine that sound in our LS400...) and any number of other engines that we don't have.

Honestly though, at 6500' elevation, making NA power is a silly pursuit. You either make more revs, get a bigger engine, or to turbo. Trying to optimize a small NA engine at this altitude is really just chasing your tail for a few hp, not at all what anyone with a budget would call economical improvement...

And first guy I want to look up is the one with the MkIV, NA with ITBs. :)
I don't think he will be a problem...
For some reason I want to say his name is Brandon? Goes by NAHERO on here I believe. It's a pretty badass car, made respectable numbers in Vegas a few years back, only revving to about 8k, surprisingly, and I think he made over 300whp.

I was impressed, considering the huge meats that car was spinning on the rollers...


Anyway, to the OP, what are you going for here? What is driving this desire?
 

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I've entertained the idea long enough to know that I simply will NOT spend what it would take, between time and money, to make it happen on any of our cars. Shame, really, as Miatas sound damn good with ITB's. So do 1UZ's (I can only imagine that sound in our LS400...) and any number of other engines that we don't have.

Honestly though, at 6500' elevation, making NA power is a silly pursuit. You either make more revs, get a bigger engine, or to turbo. Trying to optimize a small NA engine at this altitude is really just chasing your tail for a few hp, not at all what anyone with a budget would call economical improvement...
I think you definitely need forced induction for max power, like sixpack said, and I also think from an economical standpoint you get a lot more power for your money that way for sure.

I wanted to have better throttle response (plus I just thought it would be fun to go the ITB route), but I had the block bored/stroked, had the head lightly ported/polished, and went with a different turbo/manifold setup all at the same time. The car feels great, but unfortunately I didn't get to see what difference the ITB's made on their own.

I would also suspect that ITB's might behave differently in an NA application as opposed to forced induction. I wanted the best of both worlds but now I wonder if the benefit of ITB's are more impactful on an NA platform? Either way I think forced induction is the way to go if you just want more power, but I could see why someone would want to go NA ITB's if max power alone wasn't their motivation.

This is my setup right now:



 

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Displacement should be just under 2.4L and around a 9.5:1 compression ratio , I remember we cc'd the head and measured the block deck height after machining as part of the piston ordering process but I would have to look through my records to dig up all of the measurements.

I went with a stock RB26 crank in my RB20 block w/ RB20 head, RB26 eagle rods, and CP pistons (I believe they are 82mm up from the stock 78mm if my memory is correct)
 

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Personally the only reason I'd do ITB's is for the sound. Have always wanted to, but the expense is always on the other side of the "is it really THAT good?" argument.

However... putting together an Exocet soon. A ~1500 lb car with a K24 with ITB's and 8k+ rpm? Sounds good to me!
 

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ITB's enhance throttle response quite a bit, and on an NA engine would allow for easy tuning of different intake runner lengths to get the right length for your engine/cam combination.

The problem is that ITB's add tuning complications, and don't instantly make any given NA engine a screamer. I suspect a 7M-GE would need a substantial amount of headwork, oversize valves and bigass camshafts, and a bottom end combination that bumped compression signficantly, as well as a properly designed equal length header to really take advantage of it all. NA engines are fairly all-or-nothing in that way. Omitting any one of those steps would significantly degrade the results.
Best guess based on other engines I've seen, I'd be pretty excited to see a 7M-GE built to such a standard make 260-270whp or so. It'd sound heavenly, yes, but it'd also cost more than most 2JZ-GTE conversions.

If I had a lot of money and time, and a clean MKII that needed an engine, I'd absolutely do a hot 7M-GE ITB'd setup. But for a MK3 I just can't really get excited about an NA build that isn't at least a 1UZ or something with more displacement to move around all that weight.
 

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Jeff, when I had my 84 (think I sold it in 2014?), I had serious considerations about either putting on a triple Mikuni side draft setup, or swapping in a 3SGE Beams engine with the 6-speed from the Altezza.

Realizing I wasn't quite there on either idea, I decided to let the car go so I could focus on the Mk3.

Oh, and speaking of 1UZ ITB setups...

 
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