DBW on aftermarket intake manifold

[johnny g]

Hi everyone,

 

I'm currently looking at building up the VVTi in my car, and doing someting a bit different with it. One of the first things that's causing me a headache is the VVTi intake and the DBW throttle.

 

I want to future proof the build as much as possible, so I'm basically looking at the largest throttle body I can find, I know most of the non-VVTi guys like the Nissan Q45 TB (also had one on the MR2), but I I do like the DBW throttle, because i'm using Syvecs ECU and that can use the DBW (amongst other things) as part of the T/C strategy and also for the safety features.

 

I've seen a few of the Chevvy LS2/LS7/LS9 throttle bodies that are 90mm, DBW - http://www.corvettegarage.com/product/gm-ls2-90mm-throttle-body-for-corvette.html

 

Can anyone offer any information on how difficult it would be to mate that TB on to the intake? The rest I'm guessing is just harness work that I'd have to ask Ryan to do for me.

 

Thanks in advance! Am open to any ideas on this to keep the DBW!

[Wez]

Subscribed, could be good for retro fitting DBW with a syvecs onto none DBW cars

[johnny g]

Nothing? Would love to see some of the respected opinions on this, or maybe alternatives?

[johnny g]

I've done some looking around, to see what people are using to replace the Nissan Q45 TB, and the general view is a Nissan QX56 Throttle Body seems to fit the bill.

 

I'm trying to find out if this meets the same bolt configuration as the Q45, if it does, then it's a bonus, if not, then it's adapter time. Either way, there are plenty of 90+mm DBW throttle bodies out there. The Corvette range are now DBW, but are very expensive. The QX56 is a fair bit cheaper.

 

Will keep digging.

[johnny g]

Ok, I've taken the plunge, bought a Greddy-stlye intake and an LS3/LS9 Corvette (2009 model) 90mm electronic throttle body.

Will keep the details up to date in my build thread.

[Chris Wilson]

Are you aware of the potential issues that oversized throttle bodies can cause to drivability? I see this regularly on Skylines where the first quarter of throttle opening is like a switch and the last 3/4 's does very little. It's very important to size the TB area to the engines air flow needs. A better way is to do what Mazda did with the FD engines and have multiple butterflies, the smaller one opens for normal driving and the larger one comes in beyond 2/3 throttle. It makes for SO much nicer drivability. Bigger is most definitely not always better. Not sure if you can calibrate drive by wire to give none linear operation, it sounds like an extra nightmare to me

[johnny g]

Are you aware of the potential issues that oversized throttle bodies can cause to drivability? I see this regularly on Skylines where the first quarter of throttle opening is like a switch and the last 3/4 's does very little. It's very important to size the TB area to the engines air flow needs. A better way is to do what Mazda did with the FD engines and have multiple butterflies, the smaller one opens for normal driving and the larger one comes in beyond 2/3 throttle. It makes for SO much nicer drivability. Bigger is most definitely not always better. Not sure if you can calibrate drive by wire to give none linear operation, it sounds like an extra nightmare to me

 

It probably will be a nightmare, Chris - but I just want to try something different to be honest. i've driven a couple of Supras with 90mm TB's and they're ok. I'll be keeping hold of my stock intake and my stock DBW throttle, so I can always revert

[johnny g]

Parts bought to make this work are:

- LS7 Throttle body, 90mm, GM Part # 12605109.

- OEM LS7 Connector + wiring from Current Performance; http://www.currentperformance.com/Connectors/LS2_LS7.html - Black 6 Pin Female Sealed GT 150

Push-to-seat

- intake manifold of your choice

- Syvecs (or other DBW capable ECU).

 

Work will need to be done to have the TB attached to the intake.

 

I've ordered the bits, just need to make it work now.