Suzuki GSXR 750 quad Throttle Body Install on 2.3 L Duratec

[JohnStranahan]

For the sake of argument lets consider this a track car or a car that will be driven in Kansas which has a lower standard on emmisions requlation.

I have started this project already. Some photos can be found here.

http://journals.aol.com/johnstranaha...ing/#Entry1633

More photos in the second topic just below that one in my Journal.

The plan is for an intake system similar to those found on race cars using this 2.3 L Duratec Motor. Horse Power plans are modest 200 -225 HP at the engine, but naturaly aspirated horsepower for good throttle control on an autocross course or road coarse. These gains may not be realized until a full exhaust is available. Stock Pistons and Crank will be used. Now my plans are to also meet current emissions test except for the visual inspection. My plans for this thread are to gain some knowhow in the areas that My nephew James and Myself (John) are lacking. We do have some schematics and wiring diagrams available and some sketchy information on the function of the various tuning motors on the stock intake manifold. Here are some questions to start with.

I plan to inject EGR through a copper manifold. (I know that a pure race car would just omit EGR). The ouput out of the head is a EGR tube that threads into the right front of the head about 4 inches long by 5/8 inch diameter. From the engine schematic it looks like this tube may be water cooled out of a curved oblong port in the head. I would need to deal with this. Does water come out of the head there and then where does it go. Does it heat the intake manifold and return to the area between the two, center, intake ports. If you have had your intake manifold off you probably know this. Mine is not off yet. I am looking to buy or have a stock manifold donated for the project. Once I have the used manifold in hand a lot of my questions will be answered.

The suzuki throttle bodies have a secondary throttle plate that is used on the motorcycle to keep up the intake air velocity at lower RPM's. I plan to actuate these possibly with the Ford OEM runner control that opens at 3000 RPM. Does anyone know if this opens sudenly or gradually. Some test on the engine itself will tell. I am not to this point yet. The Suzuki 42 mm throttle bodies may be a tad on the large size but the secondaries could be adjusted to not open fully.

I have made an idle air manifold that will be fed by a stock Idle air control motor.

John

[Oreo]

EDIT: I saw your website & realized you are tryign to fabricate a set of ITB's.

Have you figured out how to tune the OE ECU to handle the MAP sensor? My understanding was that you needed an aftermarket engine management solution for this. (Which will completely eliminate any ability to pass an OBD2 emissions check FYI.)

Beyond that, IMHO, I think you're reinventing the wheel to such an extent that you would be better off just purchasing an off the shelf solution. Sorry man, but a lot of intelligent minds have poured over the available options.

Also, in your blog you mentioned a concern for poor throttle response as the reason for using ITBs instead of the Cosworth manifold. Are you aware of the OE TB's design features that are specifically designed to cause slow tip-in response? Fantastic success can be had by porting out the stock TB. It sounds like you've got the right equipment to handle that.

And finally... Pics please.

Originally Posted by Oreo's original post:

It sounds like you're taking on a very ambitious project. It also sounds like you need to do a lot of research here before you go buying any more parts.

First, you simply can't make any more then about 185whp NA on a stock D2.3 intake manifold. This is well known & documented here. If you're trying to break 200whp, you will also need to upgrade your pistons to 11:1 or 12:1 compression.

Second, the stock duratec TB is about 63mm ID. The aftermarket ones are 65-67mm ID. I like the 2nd plate idea in your Suzuki TB, but 42mm just ain't gonna cut it. And, no offense, but if you had done your research here first, you would have known that... so please, for your own sake, ask questions here FIRST.

Here is a recommended reading list I've compiled just for you. The first link is to all the threads where an old member by the name of Walter Marcy posted. He died, but he pretty much wrote the bible on NA D2.3 modding. http://forums.focaljet.com/search.php?searchid=342880

2.3L 200+whp Salad:

• Cold Air Intake (FocusSport, F2, or a used Cosworth if you can find one)
• Intake manifold (Cosworth is the only option)
• 1-3/4" or larger Header (Talk to our sponsor F2)
• Minimum 2.5" mandrel bent Exhaust
• Stage 2 Cams with valve springs and retainers
• Minimum 11.5:1 compression Pistons and rods (12.5:1 cr is even better)
• Dyno Tune and hardware (SCT's Xcalibrator 2)
• Miscellaneous components (Injectors, BS Delete, Plugs, Oil, Gaskets, etc.)

All told, you're looking at about $4000, plus install labor if you can't do it yourself.

As far as the 2.0L goes, it takes essentially the same parts, but compresion must be 12.5:1, and you'll need to rev the engine an additional 800-900rpm.

In both cases, there is some other hardware that should be considered necessary. You should have a light flywheel, clutch, gears and differential. You should also have an appropriate suspension and brake system that allows you to remain in control of the power.

[Z63R]

Oreo, thank GAWD you've retained some of the stuff I seem to have forgotten... Well said, sir.



Meanwhile, back at the Bar D (for Duratec) Ranch...

Though the thread title says "quad throttle body" I don't see how an air metering device developed for a 750 cc displacement would benefit a 2261cc displacement especially when final power figures are taken into consideration...

Now, I haven't checked Mr. Stranahan's link, but let's say we're shooting for an even 200 at the Duratec's fly... Do Suzuki GSXR 750s make 200 HP? I honestly don't really know. I know that Hyabusas do, but they're almost twice the size as teh gixer.

[Oreo]

Edit: nevermind.

[geostef]

that setup is very common in UK ,the land of NA aspirated Duratec. There are complete kits to be installed offered by several companies though their price is a bit salty. If you need any info just give a PM.

[JohnStranahan]

"Second, the stock duratec TB is about 63mm ID. The aftermarket ones are 65-67mm ID. I like the 2nd plate idea in your Suzuki TB, but 42mm just ain't gonna cut it. And, no offense, but if you had done your research here first, you would have known that... so please, for your own sake, ask questions here FIRST"

I need to clear up some misconceptions. Firstly there will be four throttle bodies used at once (not one) effective area would equal an 84 mm single throttle body.


I am running an SCT tuned motor already. 6% additional fuel. It passed inspection. There are no trouble codes.

Not looking for 200 wheel horsepower, but 200 225 engine horsepower. This is but a modest increase over what I have now.

The only part of the stock intake I will be using is maybe the first two inches off the head. The throttle bodies will go there.

I will be drawing air over the stock MAF sensor but it is now placed in a much larger Cosworth intake tube.

Thanks for the interest.
John

[Egz]

Wait, so is it installed already, or the SCT tuned engine is still running a MAF/single TB?

I'm also curious how you will adopt the MAP setup. Keep us posted.

[JohnStranahan]

My plans on the MAP. I have built a ported vacuum Manifold near the back of the throttle bodies. This will go to maybe a small chamber that will allow the stock MAP/AIT to work as normal. I am thinking of using the extra snorkel on the Suzuki Air box for this chamber.

No it is not installed already. $150 of Suzuki parts and maybe $50 of fittings at this point. It is just a hobby. The SCT tuned engine is still running a single throttle body and stock intake manifold at present.

Pics are here in my Journal and in a topic below that shows a factory offering of this system.

http://journals.aol.com/johnstranaha...ing/#Entry1633

John

Oreo-Sent you a PM. Do you still have that manifold for sale.

[Oreo]

I still think you're trying to re-invent the wheel unnecessarily. 200 hp at the flywheel is easy on a D23 with off the shelf parts. You must really like to tinker to have taken on this project. I hope it's worth the headaches.

[JohnStranahan]

Here is a pic of one of many factory offerings. Cosworth has a similar system for sale with Barrel Throttles. All of them require custom engine management computers. My system is a bit different in that it will use the factory computer and cost $3300 less.

[Egz]

Originally Posted by JohnStranahan

My plans on the MAP. I have built a ported vacuum Manifold near the back of the throttle bodies. This will go to maybe a small chamber that will allow the stock MAP/AIT to work as normal. I am thinking of using the extra snorkel on the Suzuki Air box for this chamber.

I'm very curious on how that will all work out. I've been thinking of how to handle that, and I still get hung up on this part. You are on the right track!

[Oreo]

My compliments to your ambition. That's for sure. If you keep a steady flow of pics comming, this will no doubt be the most interesting thing to happen in this forum in about a year!

[chewbacca]

i saw all the pics of your EGR setup, but why not just tune the EGR system out of the car with the X-cal? thats how my car is now with my tune from FocusSport.

[JohnStranahan]

I made a decision to keep most all emission systems so the computer would not throw a trouble code and also to keep emissions low. I have a suspicion the EGR turns off or down at wide open throttle to achieve maximum power, but I don't know this to be true. It is off at idle.
This is reinventing the wheel, but the actual wheel is very expensive and does not control emissions.
I don't think my version of the SCT has the ability to turn off the egr trouble code. It does have two settings that are going to help the project. The first is WOT percentage of fuel. This can be upped or lowered in 2 % incrememts. Very fortunately (Randy leaked out to me in a phone converstion) it also tugs the entire fuel map up with it having the most effect at WOT. I added 6% WOT fuel to fix a bog around 2500-3500 RPM. The engine has never run better in the corners.

Another feature of The SCT is the ability to raise the fuel pressure. The way I understand this is that the duty cycle will remain the same but slightly more fuel will be delivered due to the higher pressure. This allows me to raise or lower the entire fuel map equally at high and low RPM.

Timing can be adjusted in narrow RPM bands. This will be helpful to tune the new system as well.

John

[Focus_wrc07]

Yes, definately keep a steady stream of pics coming, and keep us posted.

This is a very interesting concept, and I too am curious how you're going to make this setup work with the MAP/IAT, and everything.

[JohnStranahan]

Here is a pic of the throttle body about ready to install to the manifold. It is upside down. All these tubes will be more or less hidden below the throttle bodies.
Some unresolved issues. Suzuki has a very similar throttle position sensor as the ford unit. If voltages match up it may be usable.
Throttle cams from the stock throttle body will be used to have proper accelerator feel and wide open throttle position. I need to aquire these. A spare stock intake manifold may be on the way.
Susuki has an extremely nice stepper motor drive with gear reduction to drive the secondary throttle plates. I will have to build linkage for a possible vacuum operated ford drive from the runner control butterflies.
MAP/IAT will go in a small chamber (can) that that will quickly respond to vacuum change and that will average out vacuum pulses. This will be driven by rear ports that I have drilled into the throttle body through an existing unused boss. It will be in the air box and will respond to temperature by conduction to the can.

Of course my existing two questions in the first post are unanswered. They will be when I get a hold of a used manifold but any head start here would help. I plan to fabricate a small cover like a thermostat cover for the egr pipe area if the pipe is water cooled outside of the head.

About the horsepower on the motor cycle, it certainly is not throttle body limited as the combined area of these throttle bodies is more than enough for 2.3 L in a race motor. On the Motorcycle it is displacement limited as all else is pretty wild. Some of the aftermarket offerings for the Duratec use 35 or 38 mm throttle bodies. I did not have much selection in size to be able to choose exactly in that area.




This is a picture of the Suzuki Air box. I have modified it with a 4 inch Flanged inlet from Spectre. On the left is a row of connectors for the front of the throttle bodies. On the right is an unused inlet that may serve as a space for my vacuum can.

[Z63R]

I will continue to watch this with interest...

[Focus_wrc07]

Exactly. I will be watching this as well. My only question is, what are the Duracells for? Just wondering.

[Z63R]

what are the Duracells for?

My guess is that they were the closest thing laying around to wedge the airbox up for the picture... taped together because just one would roll...


Right on.

[Focus_wrc07]

That could be. Like they say, everyone trusts the copper top.

[JohnStranahan]

Well you have seen the ad where the Duracell bunny starts the entire East Coast generating grid. I thought they would start the car and be lighter. Just kidding.

Here is some more little progress. I found a picture of an F2 customized Duratec head showing the EGR exit at the far right. F2 head Pic below. It looks like there is no water jacket exposed there at least on this custom head. The cavity between the two center inlet ports appears to be a dry cavity on this head as well. I am hoping for the same on the stock head. It will be easy to hook up my copper manifold to the egr tube coming out of the head with some suitable fittings. I will try and order a spare to get started.

The second picture is another view of the airbox showing the short trumpets that will come out of the throttle bodies. There is a small spacing difference between the throttle bodies and the intake manifold runners. This will be made up by flexible connectors. The plastic runner inlet will be ported and tapered to make the air travel as cleanly as possible. I found a 4 inch flanged plastic inlet at Spectre along with a 4 inch to 3 inch silicone hose adaptor. This will be attached to my cold air intake. These will both be black and lend some factory look to the installation. The cold air intake system will be mostly Cosworth followed by a Focus Sport section of larger diameter feeding the 4 inch inlet. I should be able to remove a lot of the bends. My cold air system already has an air box and snorkel at the inlet side so the filter is completely enclosed and it does not have problems with water entry in high water. Details are in a topic on the right column of my Journal.
The Suzuki airbox material seems to be ABS. I am going to try some ABS glue or maybe gas tank repair material to seal some of the openings I have created.



This view of the airbox shows the short trumpets that will help tune a little wider RPM range than a sqared off tube. This filter has been removed and the inside reshaped to maximize airflow to the trumpets.

[fordblue03]

Are you replacing the fuel injectors? A 750cc engine is much different than a 2300cc engine.
I am very interested in your build. I definitley love inginuity.

[fordblue03]

FYI Emissions are federally regulated and cannot not legally removed. States can improve upon how to regulate by requiring inspections.
Good luck on your track car.

[vin0410]

This is a very exciting thread particularly to me. I have one set of Toyota individul throttle bodies in hand also planning to bolt on the D23 engine. They are 45mm each diameter with stock idle bypass and vacum slots for brake and etc. My point of using ITB is much less for hp, but much more for a trial (Just wanna do it). I heard ITB helps power all across the rpm range with the best throttle reaction. However it is also the most difficult to tune. Today it is somehow almost extinct on production cars, with the exception of BMW M cars. Even Farraris do not use it. I do not know why, but in fact single throttle can creat almost the same power as ITBs (but not as good torque curve). Maybe it is because it is just too messy to tune it periodically? FYI the FAQ column in http://www.jenvey.co.uk/ is quite informative. I have not started my project yet, but once I do I will also post here.

[Hocky]

Originally Posted by JohnStranahan

My plans on the MAP. I have built a ported vacuum Manifold near the back of the throttle bodies. This will go to maybe a small chamber that will allow the stock MAP/AIT to work as normal. I am thinking of using the extra snorkel on the Suzuki Air box for this chamber.

You do realize that the original equipment does not incorporate a MAP at all? And that is the main reason why your tuning will not work. You will have to find some way to incorporate a MAF in order to utilize the stock computer and then you've negated any gain that there may have been from the ITB's. That said, there is a lot more math involved than 'hey, this thing has 4 itbs, my car has 4 cylinders... it'll work!' when designed intake/itb set ups.