My throttle body / ported intake manifold project (08/14/2013 Update)

[L_RAO]

Here's a quick timeline:

April 2012-May 2013
Sent my intake manifold + 74 mm Blox (B-series) throttle body to get ported. During this time, he:

• Ported the runners
• Ported the snout, getting rid of the divider plate
• Smoothed out the transition from TB to IM
• Gutted (machined) out the VVIS plate
• Made a custom flange for the TB
• Made a custom throttle cable bracket

June - August 2013
Dropped off my car at Applied Motorsports. Nick installed some Comptech cams I was able to pick up, and I thought the IM/TB would be a simple R&R (remove and replace). Not even close. We came across a few issues, with a few solutions:

1. The TPS for the NSX wouldn't work - so we used a B-series TPS.
2. The throttle cable bracket was too long - so we shortened it
3. The intake manifold gasket set from A&S Motorsport needed to be trimmed
4. A couple of the vacuum snouts needed to be re-oriented for clearance purposes
5. (We bypassed the IACV altogether)

All in all, there were 12 more hours in labor than I had planned for, and we still have the following issues:

1. Nick could not get the TPS to read a normal or "full" voltage reading. RYU has given me some suggestions on how to test, and Brian (Prospeed) says he has some possible solutions, but I wanted to get some other input as well before I dive into this one. This is beyond my experience level, but I am willing to give it a go.
2. Nick had to install a "super" return spring on the TB wheel, and as a result my pedal is really heavy. In addition, my pedal has about 3/4" of play after the TB wheel is maxed out, so I could theoretically place a lot of stress on the throttle cable if I'm not careful. RYU's solution at this time is to put a stop-peg under my gas pedal. Nick says that the spring can come off as soon as Issue #3 (below) is resolved.
3. Here's the big one: The car will idle at 900 RPM, but if you give it gas, it will not return past 1500 RPM (i.e., the TB is getting stuck with 5-10% travel left). I can physically push the wheel that last 5-10%, but that is obviously not a real world solution. And after my drive back from San Diego (2 hours), on the first stoplight off the freeway it would not idle below 2500 RPM (thermal warpage???).
4. My TCS light is on. Not sure if that bit of information is worth anything.

So, my initial suspicion is that the tolerances/clearance of the TB blade is not where it needs to be.

• I have played with the idle screws on the TB itself, and I do not believe there is a solution there.
• I am not sure if my throttle cable has too little or too much slack; I will try to reference some other (cable) NSXs when I get a chance.
• I have read that these TBs will either need to be adjusted at the TB blade (file/sand it down), or at the 2 screws that hold the TB blade in place on the shaft.

I would like some other input before I go take the TB off the car this weekend.

Thanks!

 

[gsrboy]

Had this same problem with the ITBs on my car. I had to use a spring that is constantly trying to pull the TB closed. I took it apart one day and clean the areas and used WD40 on all the joints, springs and throttle body opening. I removed the spring and it is closing perfectly fine now.

Hope this helps.

Tuan

 

[L_RAO]

Another update:

Went to the guy that built RYU's exhaust to get an O2 bung welded in, and mentioned my TB problem. Luckily, he said that he had dealt with (crappy Blox TBs) in the past and knew the fix. Basically, the TB blade and bore were not machined to exact tolerances, and it was sticking in 3 spots. This was causing the TPS issue (since WOT was never achieved), and the idle issue. Some sandpaper and steel wool solved 90% of the issues. It still sticks when the car gets really hot, I think this is due to thermal-distortion (warpage), and that a phenolic gasket to insulate the TB will dramatically help with that issue.

The car feels super nice now. I am waiting for a dyno session to open up, and as soon as it does, Brian and I will do some more fine tuning.

Tuan: Thanks for the input, and thanks for letting me ride in your car last night. That thing is fast and loud, and AWESOME.

 

[RYU]

I LOVE the way your car is turning out L_Rao. I wish mine blipped and rev'd that easily!! #jealous

Can't wait for the dyno tune to be done..then I get to drive it on the track

 

[illwillem]

This is awesome, seriously good work here. Im curious to check this out when its all tuned, sounds like you're close.

 

[gsrboy]

Loc,

Hope it all works out for Tuesday. Keep us updated.

 

[Ponyboy]

Man, I really wish you were able to test the ZR-1 throttle body. Sorry it didn't work out.

Glad your progressing on your build though.

 

[docjohn]

love the NA way.........hope you get this all worked out soon and give us some dyno plots.

 

[scammy]

yeah i think we're all watching this

 

[Mac Attack]

Looks good!

Just curious why you went with Blox though? Price, availability? It looks like there are a lot of other TB manufacturers out there to choose from. Just asking since I'm trying to source TB's for my FI plenums.

Thanks,

Dave

 

[L_RAO]

Mac,

A few reasons:

1. I wanted something in the 72 mm or greater range. Based on that my options were Skunk or Blox.

2. Skunk had just gone their PR nightmare fiasco when their owner placed a public bounty on some Internet personalities, so I really wanted to have nothing from their brand on my car. So that left Blox.

3. I assumed that billet was better than cast. Well, for throttle bodies, it is not.

If you have a range you are considering, size-wise, I'd be happy to give you my input.

- - - Updated - - -

I forgot to mention that in April I was able to pick up a set of the (very hard to find) Comptech camshafts, thanks to Shad of Driving Ambition.

I sent them and the cam caps to WPC. Here's a teaser pic.

 

[JLCoolman]

Good stuff with the throttle body/intake manifold!

Awesome find on the camshafts.

 

[A.S. Motorsport]

Very very nice setup,
When RYU gets his injection manifold you'll see the revised thermal shields with more clearance for the manifold stud.

How much did the throttle body to plenum distance change in your layout?

 

[L_RAO]

Adnan,

The TB to plenum distance did not change. What we took off the snout/neck, we made up for/added to the new flange.

I haven't had a chance to confirm yet (will do so with an infrared pyrometer), but the intake manifold does seem to be running cooler.

 

[Mac Attack]

Thanks L_RAO... I had no idea of the Skunk thing. I'm still unsure of what intake manifold arrangement I'll eventually end up with when I slap the turbos on, but I'd definitely like your opinion. Thanks!

Nice camshafts! I assume you have Comptech's adjustable cam pulleys then?

 

[L_RAO]

Mac - no, I didn't get the cam gears for a few reasons. Primarily because I couldn't find anyone who was comfortable with dyno-tuning them with the engine in the car. If I ran across a used set for a reasonable price, I suppose I could add them to my parts collection LOL.

 

[docjohn]

make sure to inspect those new valve springs and guides every couple of years with those cams.

 

[L_RAO]

docjohn - yes, I intend to.

 

[Juice]

Explain. What's the risk?

Oh, and this thread kicks ass. Following with earnest.

 

[docjohn]

Explain. What's the risk?

Oh, and this thread kicks ass. Following with earnest.

i lost my last engine to cracked valve springs and I had the full comptech IEM package.

 

[Juice]

Man, then I'm going to need some advice. I will have higher lift cams than even the Comptech (Web Cams Stage 3). I think my springs are from Supertech. Have yet to buy higher grade valves or LMA. But I can see the consequences now that you mention it.

 

[L_RAO]

Juice - you have a bit of bad information. The Web Stage 3 cams are regrinds (they grind down the base circle to achieve more lift), and they can only achieve 0.420" of lift on the intake side.

The Comptechs are hardwelded (i.e., there is actual material added to the lobe) and have 0.472" of lift.

 

[Juice]

OK, was not aware that's what was done to them. Honestly, I think that is for the best with what my goals are. I'm not breathing el'natural like you are. Thank you for setting me strait!

 

[L_RAO]

No problem. Are you supercharged or turbocharged?

 

[Juice]

3.5L turbocharged. But for the time being, I'm out of commission. Just gathering parts for when I get to jump back in, so no rush.