6G72 Intake/Throttle Body Upgrade Information

[SPD_FRK]

Upper Intake Manifold
This is a very common upgrade for many of you out there. The "standard" option for upgrading these parts has been the Diamante, or another option is the XG350 manifold. The reason for this switch is due to the design of the stock intake manifold having "squished" intake runners. This design can affect how efficient the air flows into the combustion chamber, as well as how much air is taken in. Also between the two manifold options they can increase better mid-range-high end response/performance.


Early Model Diamante Upper Manifold
Below shows pictures of the stock Galant upper intake manifold side by side with the Diamante manifold. You will see the obvious difference is the intake runners between the two. Also the other clear difference is the size of the air inlet section of the manifold before it goes into the runners. The throttle body mounting plate is also a different size (bore is larger on Diamante than the stock unit).

The differences with swapping from the stock manifold are fairly limited and "minor." When you look at a stock manifold side by side with the Diamante manifold you will clearly see how the stock intake runners are "squished" and the size of the manifold where the throttle body bolts to is smaller.The stock MAP Sensor will fit onto the Diamante manifold, but you will have to fabricate a longer EGR tube to run from the rear exhaust manifold to the upper intake manifold. This is something that can be "blocked" if the build requires that route, but for the majority of people who need to pass emissions it is in your best interest to have a piece fabricated.


The manifold is also going to set your throttle body off more to the driver's side of the engine bay due to the straightened intake runners. This is only a minor issue and you should be able to fabricate the correct intake piping for the bend needed. For some, depending on the specific build you may need to relocate the battery from the stock location.


The Diamante Upper Intake manifold has an inlet size of about 69mm, with the potential to safely increase the bore 3-4mm. The stock manfiold has an inlet size of only 60mm.



Late Model Diamante Manifold
Item to be purchased and specs published shortly




XG350 Variable Intake Manifold
This is another manifold option for those who want to make the swap. In my eyes, and even in your own (as you can see in the photos), this is the "best" choice for a manifold upgrade. The throttle body inlet size is the same as the Diamante unit (roughly 69mm). With the 3 piece type design of this manifold it is a better option for those seeking to build even more performance of the 6G72/6G74 platforms. If you are building a heavily modified N/A engine, or a boosted engine, the manifold can be seperated and a custom intake plenum assembly fabricated to fit the runners section. Doing this type of fabrication is generally needed for those running a larger throttle body such as one from the Infinity Q45 which is a stock 90mm unit (largest production TB made).

Below pictures the XG350 manifold side by side with the early model Diamante manifold. You will notice a sizeable difference between the two in the plenum areas. Also note that the MAP sensor locations are on opposite sides of the manifold as well. The EGR mounting location is about the same, but the EGR valve from the Diamante (or stock manifold too), cannot be used on the XG350 as you will see in the photo they are different. The XG350 actually uses a EGR valve that has the exhaust gas pipe running directly into the EGR valve (which makes it easy to fabricate a piece for those with emissions).



The Diamante manifold has a plenum diameter of roughly 91mm (3 9/16"), whereas the XG350 manifold has a diameter of roughly 125mm (4 7/8").


There is additional volume in the XG350 plenum as you can see in the photos of the Middle section of the manifold. Note, I have removed the valves within this section as these are not needed for my specific build. This is something I do want to look into further to make it fully functional for others who could benefit from the functionality in the entire range of this manifold's intended design. The XG350 uses a sensor/motor control on the valves to regulate the amount of air that flows through the manifold assembly and into the combustion chamber. The primary section utilizes the smaller runner diameter internally to help increase the low end-mid range torque. With the higher RPMs the sensor/motor will open the secondary valves to allow an increased amount of air flow that assists with increased torque in the mid range-high end.


This photo shows you the material that can be removed to combine the primary and secondary runner ports into one large runner section out of the plenum



Looking into the center section, with the rear part of the plenum attached you can see the plastic dividers inside that feed the primary runners when the valves are closed up. When the valves are opened the majority of the incoming air flow will enter through the larger ports of this section.



Here the rear part of the plenum is removed and shows you the plastic runner inserts mounted, and then with them removed for applications such as mine where they are not needed;



Intake runner length also has an affect on performance as well. Below shows the runner length (within 1/4") difference between the Diamante manifold, and the XG350 manifold. The Diamanter manifold (first photo below) has a length of roughly 12" to from the lower manifold mounting surface to the edge of the plenum. The XG350 manifold has a length of approximately 10" from the same locations (in this case to where the middle section bolts to the runner section).











Throttle Body
Now before you jump into purchasing these items it is important to know the details of the upgrade, and there are some differences you need to know about. The stock throttle body has an internal diameter of 65mm whereas the Diamante is 68mm. There is obviously only a 3mm difference in size here, so you have to wonder if the upgrade is worth the extra 3mm. Also, the Diamante throttle body is sometimes labeled as a "Bigger Bore" throttle body upgrade. This is in a sense true as it is larger than stock, however not one to be considered a true Big Bore Throttle Body. The majority of big bore throttle bodies will step the internal diameter up anywhere from 5-10mm, or more depending on the requirements of the engine. For the time being, the Diamante throttle body is a reasonable upgrade given the current aftermarket options available (which could very well change in the future).

Another issue with the Diamante throttle body is that the sensors (TPS and IAC) on older units are different from the OEM sensors. The newer Diamante throttle body sensors are the same size, and pin number as the stock ones, so you would want to find a throttle body from a 1999 or newer Diamante. The difference between the older (likely pre-1999) Diamante IAC and TPS sensors and those on the 1999-2003 Galants differ as shown in the photos below. The IAC plugs have the same number of pins (6), but the plug size is completely different;



The TPS Sensors are also different from the older units as 1999-Newer used a 3 pin sensor, whereas prior to 1999 they used a 4 pin sensor. The other issue with the TPS sensor pertains to those with cruise control. If you do not have cruise control on your model then try to find a throttle body without cruise control. If you are unable to find one without cruise control you can modify the throttle body to eliminate these components (will be added soon). Those of you out there who do have cruise control will notice the TPS Sensors are different how they are activated with the opening/closing of the butterfly plate. The pictures below will show you the differences from a stock unit with cruise control and the Diamante (stock unit on left).




As current options are limited for a larger bore throttle body at this time, the increased size of 3mm is minimal and hardly worth the cost. With any one of the options for upper intake manifold out there, combined with a stock throttle body the improvements will be justified in just the manifold swap. There is another option for a larger (70mm+) throttle body, but it will require some farbication and really only suited for those with heavy engine modifications. As this information is gathered I will update this section of the posting.





**This is a work in progress. More pictures and information will be added

[SPD_FRK]

Mods/Admins I would like to keep this post (2nd of the thread) reserved for more space for the updates on this subject.

[beam514]

before this is locked..

don't forget about the GTS manifold

[G-spot]

I don't like to ask wierd questions but what year Diamante came with the XG350 manifold?

[beam514]

The Diamante never came with the XG350 manifold. The XG350 is an entirely different car (hyundai)

[G-spot]

Oh that's why...

[SPD_FRK]

before this is locked..

don't forget about the GTS manifold

The GTS manifold will be added as well. I haven't found a 3g Eclipse in the yards yet here, but when I do be assured that manifold will have the same information posted to this thread.

I don't like to ask wierd questions but what year Diamante came with the XG350 manifold?

The Diamante never came with the XG350 manifold. The XG350 is an entirely different car (hyundai)

Well its not really a wierd question, and honestly may be something many of the others are not aware of. The early model Diamante's (think it was a 94-95 but have to double check), has a manifold almost identical to that of the Xg350's 3 piece design. The only noticeable difference is that the intake runner section is not a solid cast piece like the late model Diamante manifold, or the XG350. The ealry model Diamante 3 piece manifold is cast with the runners in pairs, but there is a gap for air to pass between them. I will hopefully be returning to the junk yard to pick this manifold up and pictures/specs will be added.

[Jeffylou87]

This should be a sticky..

[beam514]

Just curious, do you know what year Diamante that TB and manifold came from?

Mine is from a 2002, and both sensor plugs connections fit. The Diamante IAC has 3 pins, and the Diamante TPS sensor plug connection is the exact same size and shape as that on my old Galant TPS
here are some pics:


EDIT: I was wrong. The Diamante IAC plug is different and I needed to splice in the extra Diamante IAC plug (came with the engine) onto the car harness.

[SPD_FRK]

Just curious, do you know what year Diamante that TB and manifold came from?

Mine is from a 2002, and both sensor plugs connections fit. The Diamante IAC has 3 pins, and the Diamante TPS sensor plug connection is the exact same size and shape as that on my old Galant TPS

I am unaware of the year the Diamante throttle body came from. I bought that TB and Manifold from boostzealot. You are mixing up a couple terms there in this post though that I need to clear up for you and others before confusion strikes.

The IAC (Idle Air Control) sensor should be the one with 6 pins. The one I have may be of an older year which could explain why your's fits and mine does not.

The TPS (Throttle Position Sensor) should be the one with 3 pins. The TPS sensor on the Diamante TB I have does match the plug, however it has 4 pins instead of 3. The 4th pin is likely a throttle position closed part of the TPS circuit as the Montero throttle bodies I have found w/o cruise control have the same 4 pin TPS sensor. Again, this may be a variant of the production years, or simply a difference between those with/without cruise control as I notice in the photos of your TB it is a cruise control unit.

[beam514]

oh oops haha I was typing fast. You pretty much got it but just to clear things up:

my 2002 Diamante TB has a 3 pin TPS plug connector, and a 6 pin IAC plug connector that are equivalent in size and shape to those on the 6g72 TB

Oh and I don't know if this changes anything, but my entire 6g74 (manifold and TB included) are from a Diamante VR-X

[SPD_FRK]

oh oops haha I was typing fast. You pretty much got it but just to clear things up:

my 2002 Diamante TB has a 3 pin TPS plug connector, and a 6 pin IAC plug connector that are equivalent in size and shape to those on the 6g72 TB

Oh and I don't know if this changes anything, but my entire 6g74 (manifold and TB included) are from a Diamante VR-X

Well I did some more diggig on the TPS changes/differences. The 1994-1998 TPS Sensors are a 4 pin configuration, while the 1999-Later TPS sensors are the 3 pin configuration.

It would seem that at some point the production years "evened" up with the sensors. I will have to try and find which year it starts with for the sensors to be a basic plug and plug swap.

[mysticj]

don't forget about the GTS manifold

The GTS manifold is more or less like the XG300/350 manifold with longer runners.

[beam514]

Okay so apparently I was wrong about the IAC plugs. They are indeed different sizes. Luckily my 74 came with the harness still attached, so I have the corresponding plug. I just need to figure out the pins and solder up the new plug.

[rr2swift]

i want to know if you are going to put together a kit for a N/A 04 gts, please or even a parts list, that a dumb ass like me can understand. thanks bro.

[SPD_FRK]

i want to know if you are going to put together a kit for a N/A 04 gts, please or even a parts list, that a dumb ass like me can understand. thanks bro.

What kind of kit are you looking for exactly?

[rr2swift]

it would be the intake and all that i would need to do the mod. or if you can give me a parts list and i can try and find it all. thanks

[SPD_FRK]

it would be the intake and all that i would need to do the mod. or if you can give me a parts list and i can try and find it all. thanks

I would assume you are looking more towards the XG350 manifold and variable intake electronics correct?

If so I am currently putting that project on hold for the time being as I have others ahead of this one, but be assured I have a source for full support and build data for the electronics at this time.

[rr2swift]

thanks brotha, i want to do a n/a power build, after my money comes in gonna be looking for some help, to blow it out and put it on the map, full build, and hoping my dream of turning it into a awd v6 tunner, but for now i will sit on my hand and wait for you. my number is 708- 845-6841. lets pick each others minds and see what more can be done. and yes i will buying back my 03 evo8 haven a hard time finding it, it been 4 yrs, i want my babe back.

[mysticj]

The XG350 style IM should fit the 6G75, I dunno about if the TB will bolt on. I'll imagine the torque will be huge.