I have been a pro auto repair tech for the past 10 years but for practical reasons  I have limited experience with high perf stuf

I got a 94 tracker 2 door tintop the second day I had this rig I replaced the exhaust with 2 1/4' pipe from the colector to the 1 3/4" glasspack and 1 3/4' taipipe I did this for improved flow and better sound I honestly don't know if this did any good as far as actual performance

  I have noticed the engine has plenty of low end pulling power but higher rpms 4,500 rpms and up are weak! to put it bluntly it sucks trying to pass trucks and motor homes on the road!
I suspect this is suzukis engeneering for off road drivabilaty I'm thinking  valve timing  would help but the throttle body is also restrictive.

Looking at the TBI it seams the air has to make plenty of turns before it hits the combustion chamber. I am wondering if mounting the throttle body downdraft is really nessary? why not sidedraft?  
I can't think of any cars that have tbi mounted sidedraft. but plenty of carbs have been mounted sucesfully sidedraft and work well on smaller high reving

engines any thoughts?



   

Side draft carbs are made that way.  Meaning flote levels, gravity and such have been taken into account.

With a TBI all the fuel come out of the injecter sitting over the throttle plate.  I think you would be alright at higher rpm's but at idle I think gravity would be stronger than the intake of air and fuel would run down and out of the Throttle body.

I have been cosidering the same thing,
dual side draft TBIs, the fuel is sprayed
right between the throttle plate and the body,
so there is not much of a problem there as the
fuel would get sucked right into the manifold, and
duals would let the Project Turbo Sidekick run full
boost   lets see full boost = 160 HP ahh passing
bliss, no more worries on that, now if I just had a
20 Gallon gas tank ............

You can always try it.  I haven't seen a zuki toilet bowl(TBI) but the way a chevy works I'd be sceptical.

TBI should run any way up. I wouldn't think you would get much benefit from remounting but if you can remap the stock ECU (may not be necessary) then you could try boring it out. It tapers significantly at the throttle butterfly. Its only 45mm stock so 50mm would give a 20% increase in size. You would need to source another butterfly and open up the manifold to suit. I'm looking into this at the moment as I have a spare TB. As a comparison the Swift GTI boys have had good results using a 60mm throttle body from a Nissan with no other mods (Swift uses a MAF though), I don't know what size the stock Swift TB is but it could be a bolt on power increase for 16V motors.
Wildggody: I started looking into using the weber 45DCOE throttle bodies but have you seen the cost for the bodies and a manifold? Ouch.

vacume is high when the throttle is closed so fuel should just defy gravity and suck right in. I'm thinking starting up cold may be an issue?
I have a lot of experience with drivabilaty and learned alot about what engenieers have taken into account when plotting fuel/timing curves so remapping the ECM is something I am trying to avoid(I admitit no experience= fear). I have thought hard about grafting honda port fi onto this engine because of the ease of tunabilaty with aftermarket ECM's  but then we're talking some big $$ to do it.
I have closed my shop and taken a job here: www.freemanmarine.com I am a fabricator now and work primarily with aluminum so I have the equipment handy to cut and weld a manifold.
So for now I'm thinking about just finding a bigger throttle body with a injector of close flow and making it fit the manifold sideways a good size plenum should makeup for moderate sins ....  duel sidedraft tbi?,  I thought about that too. but didn't want to add too manny factors into the mix. anybody have a messed up manifold? I could hack up? nuthing vertured nuthin destroyed:)

I haven't looked into the stock ECM. I'm designing a replacement for it that will be remappable. I'm planning on using a wideband 02 sensor so it will be an improvement over the stock item and I should be able to make it self tuning. I don't think there will be any problem with the TB on its side. There are lots of motorcycles out there that run them and if you have a look around the web most manufacturers state that their's will work at any angle. The engine is always sucking air in and that draws the fuel in (its also under pressure so its capable of going a long way anyway). There is a guy over here who converts 413 manifolds to sidedraught to fit an SU type carb so your idea is feasible. I just don't think you will make any real gains from it though. The stock ECU may be able to handle a bigger throttle body without remapping, it measures the manifold air pressure and air temperature to determine air mass. It just depends on whether the MAP sensor will allow for any significant amounts of extra flow, I guess until someone tries it we won't know. I think its unlikely as restricting the range to what is only probable with the stock components would allow a better resolution. If you change the injector you will need to remap the ECU. Changing the throttle body may cause problems with different value TPS and all the idle speed control circuitry will be different. You will also need to ensure that the in tank fuel pump is compatible with the new fuel pressure regulator. You can keep the stock injector and cheat the ECU though, I believe Wildgoody has done this on his turbo motor. I assume you have junked the stock intake piping already?

Rhinoman, if you think the DCOE's and manifold are bad, check out the fuel injection throttle bodies that TWM Induction sells.

Bolt on for Weber carbs and you could probably still get the manifold from calmini by itself.

Cost is about an arm and a leg.  

Seriously though if money wasn't an object I'd at least have to consider using them with an aftermarket EFI setup, custom intake manifold/airbox and turbo setup.  Can't beat individual throttle plates for throttle responsiveness.  Oh yeah they look really sexy too.

http://www.twminduction.com if you want to see some pictures of em for other stuff since they don't make a specific application for us.

I think I'm just gonna go with a cheap and dirty GM 60 degree V6 though at this point.

Oh yeah one other thing, why are you reinventing the wheel? Have you looked into something like Megasquirt for EFI control?  At least the hard part of designing one is out of the way that way and you only need to tune it correctly.

There's a couple of kit style wideband O2 meters you can get for around 100 bucks that use a VW/Bosch wideband O2 sensor too.

dang I forgot all about motorcycles, yea I have seen TBI on some bikes

 I would like to know more about wideband 02's

I was planing to fool around with fuel pressure and resistors in the coolant temp sensor wire if nessary.  
This system particular (8v)doesn't use an mass airflow sensor so that's not an issue.  The map sensor (Manifold absolute pressure) actualy just reads vacume on a normaly asperated engine so unless I make a signifigant cam overlap change this should not effect map voltages.
I would like to use production stuff because I live remote ,  this is my daily driver and it's nice to be able to just go to the local parts store and ask for off the shelf stuff.

any suggestions for a good throttlebody to look for in salvage yards?  I know GM is are out since they are designed to run low pressure like 12psi and the zuke is like 40psi .  
 

Exchange the tbi for a larger 60mm or 70mm butterfly, weld some injector bungs into the intake runner and mount 16v engine injectors, wire them all in parallel so they all fire at same time.  Most gm efi sistems are batch fire anyways, should work good.  you might even go with two smaller butterflys andrun  really short runners, should give you some extra ponies.  

The new Megasquirt when it comes out should be pretty good. But I like to do things my own way and I plan on using as many stock parts as possible so I will have to write my own software for the Idle Speed Control stuff too. I looked at the WB02 project, its good but I want to combine everything into one box and if poss cram it all into the std case so it'll be a direct replacement plus a few extra wires. I didn't have any luck with NGK but I've talked to Bosch about the LSU4 sensor and they've given me the datasheets for it. Those TWM throttle bodies are the sort I was talking about - like I said, ouch!.
If you want to know more about wideband sensors the WB02 project has loads of info, except the exact details on how to make them work (you need to control the heater to keep the sensor between 750 and 850 degrees C!! and then control the current through the sensor)
The MAP sensor may not an issue but the fuelling map may be, if you put loads more air through the pressure in the manifold will fall. If that combination of rpm and MAP reading isnt mapped (way too many maps here!!) then the fuelling will be out. Remember that the 02 sensor isn't taken into account under acceleration or heavy loads (unless the system uses a wideband sensor)

The wideband O2 is a kit form, can't think of the name of it but I think it's only a little over 100 bucks.  I'll try and find the name of it and post it.  A few guys on one of the Datsun boards I frequent have used it and speak pretty highly of it.

The only thing holding me back from doing
a custom multi port, multi butterfly intake
is the coolant flows through the stock manifold.

I should just bite the bullet and make one, I really
thought I could make the stock system work with
the turbo, but now I have found the max pressure the
stock injector can handle is about 85-90 PSI, any higher
and the pintle can't open from the exessive pressure.

I need double the fuel the stock system supplies, stock
fuel PSI is 34, to double your fuel flow requires 4 times
the fuel PSI, or about 140 PSI, a no can do for the stock
stuff, I did consider a CIS MAF type system from a VW
or Audi but the dang manifold problem again.

I got a couple of weeks off still so once I get a few things
cleaned up, I'm going to start on the EFI suplimental system.


I have the MegaSquirt computer built, and I have the injector
bosses and injectors, I just need to carve up the stock manifold
and graft them on, then I can reduce my fuel PSI, I hope the high
pressure has not harmed the stock injector, I notice when I turn
down the fuel PSI it runs funny, even at idle, might be the computer
has learned and adjusted to the increased fuel PSI and needs to be
unplugged for a while so it can re-learn the new lower pressure.

So RhinoDude what do you think about 4x20mm throttle butterflys ??
or would 25mm be better? Do you think the torque would suffer with
a turbo force feeding the motor? And when you gonna be finished with
that EFI? I want to hear about how well it works.

The wideband kit isn't a lot of use on its own except for tuning its only an AFR meter and the Megasquirt isn't programmed to utilise the wideband sensor. The web site is:

http://www.techedge.com.au/vehicle/wbo2/default.htm

Four 20mm butterflies are too small, you have to look at the cross-sectional area of the intake. The stock intake is 45mm which is 1590 sq mm. A 50mm intake would give 1963 sq mm, a 23% increase. Four 20mm butterflies only gives 1257 sq mm. A 60mm intake would give a 78% increase in area.

I should have a working EFI in a couple of months, the real problem is that there are so many options that its difficult to decide on a spec. I have some processors already and have done most of the design schematics. Just to make life a little more difficult my laptop has gone U/S so I need to fix it or replace it before I can do any datalogging.

I would go with one larger butterfly then then four smaller ones, the smaller ones giving you more drag in your air supply.  Have you looked into getting a setup off of a large street bike?  They have fairly large butterflys.  As far as coolant line around the intake, you only really need it in winter, not good at all in summer, so how about wrapping it with flexible copper line and some zip-ties?