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Discussion Starter · #1 ·
A couple of years back I posted some pics of an EFI conversion I did to my 2L powered hotrod using Suzuki GSXR throttle bodies and Megasquirt.

Recently I did a complete upgrade to MS2 and decided to also redo the entire installation to make it more maintenance friendly and cure some air leak problems on the manifold adapters.

The new adapters are made from 10mm aluminum plate and have the Suzuki manifold stubs welded to them. The suzi manifolds are oval shaped at the mouth and had to bored out to 40mm the suit. The new manifolds have orings rather than gaskets.

I also machined up some rings to fit over the throat of each throttle body so as to mount the air cleaners. Something else that had been bugging me for quite some time.

All in all I am quite happy with the end results and she runs sooooo smooth.
 

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Now go out and drag a knee on that thing! Wish I can hear the motor on your car. Must be really smooth as you said. Looks very nicely done btw.

From what GSXR motor are the TB's from? I'm guessing MS2 is the brain behind all of this?
 

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Discussion Starter · #3 ·
From what GSXR motor are the TB's from? I'm guessing MS2 is the brain behind all of this?
98/99 600 or 750 Mikuni. These ones taper from 48 to 40mm and have a more acute injector angle than the later types.

I have a MS1 card and another upgraded to MS2. So far I've had more success tuning with the MS1. Haven't figured out why just yet.

When I'm satisfied that I've got the fuel side of things right with MS2 I'll attempt to do the spark as well.
 

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Did you space the TB's farther apart than on the stock bike? I have a set of GSXR TB's I wanted to use but they are closer together than the Alfa intake port spacing. I didn't want to have to angle the mounting if I could avoid it.

Good job, looks great!

Larry G
 

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Discussion Starter · #5 ·
Did you space the TB's farther apart than on the stock bike?
Yep. GSXR are only 80mm apart like most bikes.
I used a length of 6mm all thread, some 3/8 stainless tube, and a piece of steel strapping. The all thread replaces the long bolt that holds the TBs together and the ss tube is cut to size to act as spacers. The strapping replaces the aluminum strapping on the underside.

The adjustment tabs between each TB were simply bent to suit. I could have welded longer tabs on but I'm too slack.

Once it's all together it takes a bit of mucking around to align it all up so as to prevent sticking but once that's done they're perfect.

Oh, and you'll need to make up a new fuel rail as well.
 

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What did you do in order to ensure you go a clean MAP signal to the Megasquirt? I assume you are running Speed-density and not Alpha-N of course.

Also, how did you rig up the throttle linkage? Any more detailed pictures? I was worried about the throttle opening being progressive enough for use on a street car.
 

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Discussion Starter · #8 · (Edited)
What did you do in order to ensure you go a clean MAP signal to the Megasquirt? I assume you are running Speed-density and not Alpha-N of course.
0.6mm mig tip in the lines coming from each TB into a common line to the MS.
I found this worked better than just one restricter in the main line, which needed to be much smaller for the same effect. Also no capacity damper (eg fuel filter) as they slowed the signal down too much and caused lean out on WOT.
Any extra dampening can be done in MS but not too much because I believe you need to keep things pretty dynamic with ITBs.

Also, how did you rig up the throttle linkage? Any more detailed pictures? I was worried about the throttle opening being progressive enough for use on a street car.
I used a stainless push bike brake cable attached to the GSXR crank. If you look at the crank it is eccentric therefore you get progressive control.
I get better throttle control than I did with the cable controlled carbs.
I'll post a pic "when" I fix my camera. (Memory card failed and I lost all my holiday snaps of Tasmania :( )
 

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Thats good to here that the MIG tips work so well. I wass comtemplating building a "vacuum plenum" and piping everything I need from there.

I am putting GSXR600 TBs onto my Fiat spider which of course means I have the same challenges as far as spacing on adapting to the manifold. I also need to be able to supply good vacuum for the brake booster and FPR as well....so I saw on ebay that Spica cars have what is called a "Vacuum block" which is basically a cast vacuum T with multiple ports and even one that looks big enough to run to my booster.

On the Fiat I have to mount the ITBs on a weber IDF manifold because there is no room to have a straight out "side draft" configuration because of interference with the master cylinder on the drivers side.

I am also interested in more information on how you adapted the filters to fit. I dont like the look of those small motorcycle cone filters and I am convinced the 'sock' filters are junk.


Thanks
 

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Discussion Starter · #10 ·
I also need to be able to supply good vacuum for the brake booster and FPR as well....so I saw on ebay that Spica cars have what is called a "Vacuum block" which is basically a cast vacuum T with multiple ports and even one that looks big enough to run to my booster.
I just used the standard port that alfa has on No. 4 intake manifold. I have never run out of vacuum.

I am also interested in more information on how you adapted the filters to fit. I dont like the look of those small motorcycle cone filters and I am convinced the 'sock' filters are junk.
Have a look at pic 2.
I simply turned up some 10mm thick flanges that slipped over the end of each TB and are held on by interference fit, locktite and 3 off 4mm grub screws.
You can drill and tap these to suit whatever intake you want. I wanted to fit ram tubes but didn't have enough room.

What type of GSXR TBs you got? There are several types all with their pros and cons.
Mine are Mikunis from a 98/99 600/750.
These are the best IMO if you want to keep the injectors located in the TBs.
 

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I believe mine are from a '01. Which is unfortunate I believe because they also have secondary throttles which I have to remove and plug. I have been looking on ebay to see if I could get the older ones but no luck so far.

Can you post your .msq file so I can take a look? Or perhaps just a screen shot of your VE table would be easier. I am wondering how the shape of the curve compares to a standard plenum configured car.
 

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Discussion Starter · #12 ·
I believe mine are from a '01. Which is unfortunate I believe because they also have secondary throttles which I have to remove and plug.
That should be quite easy. You can get small brass plugs like mini welsh plugs or turn up some aluminium plugs and lockite them in.

The main thing I don't like about the later (keihen sp?) ones is the injector angle. 45 deg compared to 60 deg on the earlier types.
Not a problem if you are going to fit the injectors into the head or intake manifold.
I have been looking on ebay to see if I could get the older ones but no luck so far.
Have you tried here?
http://www.gdlcycles.com/index.html

Can you post your .msq file so I can take a look? Or perhaps just a screen shot of your VE table would be easier. I am wondering how the shape of the curve compares to a standard plenum configured car.
Unfortunately my laptop's hard drive went out in sympathy with my camera's memory card. I'll pm you my msq file when it is fixed.

In the mean time suffice to say that the comparing a VE table for a plenum and ITB's is like comparing a gently rising slope to a skate board ramp.
 

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This is awesome...i have just read about 80 pages of honda mods using ITB ........ what the hell, this seems like a wicked answer for those that want to turbocharge or supercharge a car that used to be carbed........my question is this, does the gsxr throttle body come with injectors, and will those be suitable? i guess a new fuel rail is built, no biggie there, and megasquirt is fine with itb or does this create difficult tuning?

Awesome......this thread should be stickied..why would people rip off their spica system, when they could do this...carbs are 1100 prob anyways, this is way cheaper, and smoother, not to mention the expandibility.

I am seriously considering a 2.0 ts in another project car ( not my duetto, as it is amost perfectly original...respect) the ts i want to turbo, i was looking at the stock efi but this seems way smarter.....and also a good use of space...that efi sits a little high ..........:D

WE need more of this sort of advancement !!!
 

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Brett,

I remember reading about your hot rod. At the time I thought the choice of an FI/2L Alfa engine was a perfect choice. I've also enjoyed reading about your Suzuki throttle body mods and installation.

While I love Webers and and can speak pretty good SPICA, I am completely a newbie when it comes to building a Megasquirt injected 2L Alfa engine.

I wonder if you'd mind posting a list of the parts needed to prepare a Megasquirt injected Alfa? I'm so hardware oriented that once I know what's needed I can then go on to figuring out what I need to know about putting it all together in a workable car.

Thanks,

Jim
---------------------------
1970, 1975 GTV, European model, 2nd series
1962 Lancia Flaminia Zagato 3c, 2nd series
 

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Discussion Starter · #15 ·
Well Jim there are many ways to skin a cat but this is the way I did it.

98/99 600/750 GSXR throttle bodies.
MSII ECU
MS relay board (optional but makes wiring easier)
Scarp wire from various wrecks.
Inline Bosch fuel pump. (found on many euro & jap cars)
Toyota Cressida 7MGE Denso injectors. 32lb/hr (these are available in low and high impedance. I used the high ones. 12ohms, Light green)
GM sensors for coolant(CLT), air temp (MAT) and 4 wire narrow band O2 sensor.
GSXR throttle sensor and fuel regulator.
Homespun fuel rail.

Modified stainless pushbike brake cable for the throttle cable.
Ford anti diesel solenoid for fast idle control.

The whole lot cost me less than $800 aussie dollars but it ain't no bolt on option. So be warned, there's lots of modifying and adapting to make it all fit and work.
 

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The whole lot cost me less than $800 aussie dollars but it ain't no bolt on option. So be warned, there's lots of modifying and adapting to make it all fit and work.[/QUOTE]


Hi, Brett:

Thanks for the info. I'm an inveterate scrounger so it really helps to have a baseline. There's a lot of helpful information regarding MS basics but not too much relative to Alfas. I'm sure that will change. Your photos and discussion showing how you modified the Suzuki TB's is particularly interesting, especially in view of the cost of weber-style throttle bodies. If money wasn't an object, the Jenvy or TWM TB's on a weber manifold would be a no brainer. But you're way is a fraction of the cost. Besides, I don't mind taking the time to learn what needs to be done and then make it all work. For me, that's fun.

Thanks again,

Jim
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'70, 1750GTV, European, 2nd. series.
'62, Lancia Flaminia Zagato 3c, 2nd. series
 

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just curious..i posted the same question over in engine management, but no answer....using a megasquirt and this set up on a 2.0 ts how would one controll the dual coils? any guesses...
 

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Discussion Starter · #18 ·
That would depend on whether you want to control them independently or to fire simultaneous.

Simultaneous you would just need to split the output but for independent you may need 2 ECUs. One for spark and fuel and the other for spark only.

Have you tried asking this question on the MS forum?
 

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yes i asked this question in the ms but no response.......i would think that firing at the same time would be best......do you know if the stock ecu on a 2.0ts fired at same time?...this is my upcoming project...

105 gtv, swap out 2l for 2.0 ts low compression pistons, gsxr throttle boddies in air box, turbo, ms controlling spark and efi....use edis crank sensor on pulley.......also add wide band 02 sensor.........this would make for a super clean engine bay and very efficient tuning........what injectors do you think would be appropriate if i was making about 240hp ? and what brands of injectors fit with no modifications into the gsxr throttle body?
 
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