Some of you may remember I made an ITB setup for the vg30det engine 3 years ago. At that time, I also planned to make one for the vg30dett so I bought an extra set of 45mm bore Jenvey ITB's and this winter I started working on it. Because of the little space underneath the bonnet and the masses of hoses, wires etc. I needed to have an actual 300zx to test fit. A friend offered me his 300zx, it's an old one with 234.000km on the clock (even original engine) and it needed a timing belt.

 

The engine runs OK but at idle wasn't very happy. I found some leaking hoses but they didn't really help after fixing, eventually I noticed the engine is consuming oil badly and probably makes low compression on at least 1 cylinder. The valve lifters tick like hell and I'm in the process of doing something against that before the car goes to the dyno. Will be one of the last trips this engine will make.

 

Now we all know how complicated the OEM manifold and fittings are. The valve covers aren't really helping either. I decided to remove the large raised sections and weld in a new plate. The baffles were fitted back in (no pics). The coils were modified to sit lower and welded/bolted to the exhaust valve covers. I also made a custom oil filler.

 

 

I removed some material from the base of the OEM lower manifold for a cleaner fit. The pipes were than welded upon. The exact angle etc. took long calculations and test fittings so I keep those to myself.

 

 

 

The flanges were welded on and the ITB's could be mounted.

 

 

 

Further test fitting of the Jenvey velocity stacks and clearance underneath the hood. Clears no problem.

 

 

An idle collection manifold was made underneath the manifold, all copper lines with brass fittings no cheap ass hoses that can barely be used in such short bends.

 

 

The complex plenums took 2 weeks to design and cut/weld.

 

 

In order to link the cylinder banks I made a copy of the Jenvey OWK unit that pushes one wheel outside to line up with the other.

 

 

 

An idle block was made for the AAC unit to attach to and links with the unit underneath the manifold.

 

 

Eventually looks like this along with custom made hard pipes.

 

 

 

 

With all parts fitted and the wiring harness modded to fit the engine fired up instantly. I did have trouble getting the idle down. I found out yesterday 3 welds cracked and need looking after. Other than that, I'm pretty happy with it.

 

 

Now this thing will be seeing the dyno once all the problems are sorted out. I don't have a date set but I'm hoping within 2 weeks. After that, the stock manifold will be tested in the same way to note the difference.

 

As of now, I can't offer this as a production part and I guess I need to become a trader here on the forum first. So for now, this is just scientific research LOL.

I'll keep this updated.

 

-Rutger

 

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I love the look of that, great design and fit well done rudi!!!

Really cool that mate

It makes alot more space under the bonnet! Looking forward to seeing the dyno figures:thumbup1:

Looks great! Some serious work there!

 

Have you got a dyno reading before fitting this?

Fantastic work, if you do decide to make them I would be interested depending on results of course. I think on a stock Z, the power difference may not be obvious, an will come from the plenum design rather than the ITB's, but would be interesting to hear what the responsiveness is like. I also like how you've tackled the idle housing.

 

A few thoughts from my side

1) Need to think if this is compatible with some of the top feed injector kits around, or at least allows space for something to be adapted. I still have side feeds but would think that most people who would consider the ITB will also be going top-feed at some stage

2) PCV reroute. Modifying the rocker covers like you have prevents the popular pcv reroute, again something to consider

3) What's the size of the inlet plenum coupling? 2.5"?

4) Could the plenum be made in c/f to save weight, looks like it could from what I can see.

 

Good work!

wow amazing work! congrats!

Thanks for the thumbs up everyone:thumbup: I'm quite happy with how it worked out so far, just the few small leaks and the noisy valve lifters hold it back now. I'm searching for replacements for the lifters now through my old stuff.

 

Looks great! Some serious work there!

 

Have you got a dyno reading before fitting this?

I did want to test the manifold as a full OEM car at first. However, the noisy lifters and a couple of other small vacuum leaks held me back. I found that someone in the past had also installed very primitive bleed valves I was kinda worried they had made mods to the upper manifold as well. I decided to fix them along with the installation of this manifold. The car will later be rebuild to full OEM state.

I don't expect that much difference against the stock manifold on a bone-stock engine. On a highly tuned engine the power increase could lead up to 10% due to the shorter inlet tracks, improved velocity stacks and huge well shaped plenums. The inlets for the plenums are no less than 70mm, I tried to make everything as big as possible. I could make the manifold smaller for lower powered cars though, but an engine with ITB has no idle issues from a large manifold plenum.

 

I think I can make it work with top feeds, to be sure I will take a look once everything is back in place.

 

The PVC reroute can work, all I would have to do is weld 2 hose adapters to the intake manifold covers. Instead of doing the PCV reroute I would personally fit a high mounted oil catch can above the exhaust cover, lot's of space for that with this manifold ;)

 

The plenum could be made from carbon fibre, the stock plenums weigh about 1550 grams per side. That includes the flanges and bends that hook up to the ITB's. Those cannot be made from carbon fibre, so the only weight advantage may come from the 'tank' itself. At best this may spare 800 grams for both sides. But it is something I intend to develop over time and depending on interest perhaps for this engine too. The advantage of using carbon is that it requires far less labor and ridge free shape as there is no overlapping.

 

This manifold saves about 8kg's from the engine's weight. The Jenvey ITB's are also much lighter than OEM throttle bodies. The 2 stock TB's weigh 900 grams without hoses or linkages. The 6 Jenvey ITB's weigh just over 1000 gram, including all linkages!

 

I am currently also designing a manifold very similar to this one, but far less complex with just 2 TB's fitted 'sideway pointing' like on the VR38dett. I'm going to roll that one on the dyno too.

 

- - - Updated - - -

 

Fantastic work, if you do decide to make them I would be interested depending on results of course. I think on a stock Z, the power difference may not be obvious, an will come from the plenum design rather than the ITB's, but would be interesting to hear what the responsiveness is like. I also like how you've tackled the idle housing.

 

A few thoughts from my side

1) Need to think if this is compatible with some of the top feed injector kits around, or at least allows space for something to be adapted. I still have side feeds but would think that most people who would consider the ITB will also be going top-feed at some stage

2) PCV reroute. Modifying the rocker covers like you have prevents the popular pcv reroute, again something to consider

3) What's the size of the inlet plenum coupling? 2.5"?

4) Could the plenum be made in c/f to save weight, looks like it could from what I can see.

 

Good work!

I don't expect that much difference against the stock manifold on a bone-stock engine. On a highly tuned engine the power increase could lead up to 10% due to the shorter inlet tracks, improved velocity stacks and huge well shaped plenums. The inlets for the plenums are no less than 70mm, I tried to make everything as big as possible. I could make the manifold smaller for lower powered cars though, but an engine with ITB has no idle issues from a large manifold plenum.

 

I think I can make it work with top feeds, to be sure I will take a look once everything is back in place.

 

The PVC reroute can work, all I would have to do is weld 2 hose adapters to the intake manifold covers. Instead of doing the PCV reroute I would personally fit a high mounted oil catch can above the exhaust cover, lot's of space for that with this manifold

 

The plenum could be made from carbon fibre, the stock plenums weigh about 1550 grams per side. That includes the flanges and bends that hook up to the ITB's. Those cannot be made from carbon fibre, so the only weight advantage may come from the 'tank' itself. At best this may spare 800 grams for both sides. But it is something I intend to develop over time and depending on interest perhaps for this engine too. The advantage of using carbon is that it requires far less labor and ridge free shape as there is no overlapping.

 

This manifold saves about 8kg's from the engine's weight. The Jenvey ITB's are also much lighter than OEM throttle bodies. The 2 stock TB's weigh 900 grams without hoses or linkages. The 6 Jenvey ITB's weigh just over 1000 gram, including all linkages!

 

I am currently also designing a manifold very similar to this one, but far less complex with just 2 TB's fitted 'sideway pointing' like on the VR38dett. I'm going to roll that one on the dyno too.

 

BTW I can't edit my posts?

what did u do about the balance tube/bar that was on the original plenum ...

Guess its not needed on ITBs?

yeah more so as its turbo .. and the air charge/pressure still needs to be balance on Left to right bank

The T section on top of the AAC unit works as a distribution unit. Now the hose is smaller on one side, which is something that can be compensated by welding a larger pipe upon the T at that side section. The internal diameter will still be smaller on that side, but the OEM pipe is 3 times longer with 2 straight turns. Note that the vacuum block underneath the manifold also allows for a very precise even distribution of air. As it is now, the air distribution is probably better than stock.

 

I removed the air regulator. I made a provision for it though, but I decided it is not needed. The AAC unit also compensated for cold idle. The air regulator also draws so much of energy, the + wire going to it is the thickest of any ECCS part! Noticed the same on the ca18det, where the wire is hooked up to the fuel pump wiring for the same reason.

I've been having a load of trouble with the car, 2 times injector seals failed, next, the pump voltage control unit failed along with the FPR and PTU. Now the car is finally back up, after another FPR failed. Eventually fitted a brand new aeromotive FPR and it runs and pulls strong, especially for such an old engine. Taking the car to a garage on tuesday for it's yearly required road approval test/check over. The car can be driven legally to the dyno.

 

The guys at the dyno told me a dyno shoot out can be done the same day if I call them early in the morning, and since I have wednesday off that may be the big day. It's this shop they build a 1250hp R32 so they should be sorta capable of knowing what to do with this. http://www.proimport.nl/highlight-current-projects/project-el-toro-the-real-deal-r32-gt-r-1253-5ps-and-1429-6nm/

 

I thought about making a small vid of the how the car's running now but if the cops see me on the street with it I'll be in big trouble. So other than a few full throttle pulls on a straight end close to my home in the dark I'm taking no chances.

 

Nice work! I think you want to sort your cam belt out before taking it for a run however!! :lol:

amazing thread and build Rudi

Nice work! I think you want to sort your cam belt out before taking it for a run however!! :lol:

LOL, I took that pic several weeks ago when I was putting everything back together, posts without pics quickly become boring ;)

awesome!

Had to figure out how to legally drive the car to the dyno and I got it all worked out this week. So I went to the dyno today. Last week it ran perfect, but it started hesitating very bad yesterday so I was worried all was gonna fail. The fuel system was good, and the timing was set correctly at 15 degrees. I didn't knew anymore where to start. So I went with some of the basics, refitted a poorly grounded harness cable and cleaned the AFM and CAS harnesses. Then, all of a sudden it pulled correctly again.

 

Now I haven't driven this car in anger before the manifold swap, but it does feel like the standard mapping is not suited to this manifold. If I quickly depress the throttle after a gear shift, there's no response. It also feels somewhat nervous and sensitive to throttle changes, a bit like my brother's Gti-r with the OEM ITB setup. This system really needs a map 'written' for it.

 

Anyway, on the dyno all went well. The car pulled 263hp/349nm uncorrected at the rear wheels, on a warm day (29 degrees C) and the coldpipes from the intercoolers got very hot as the 2 coolers they had were not that powerful. I estimate the inlet temp was around 45 degrees C. During the other pulls the power went down as the engine heated up even worse and the operator couldn't get a good pulse from the ignition system, the output was therefore measured in speed not rpm's.

 

The blue line is the first pull. The torque values are incorrect, they had some trouble getting the dyno system to correctly convert. Explains the weird 800+nm spike. Realistically, it's about 350nm at the wheels.

 

 

 

Now I'm not directly converting the car back to stock, there's another type of manifold that I want to try on the dyno. Roughly the same as this one, but with the stock TB's. Will make a different topic for that.

Had to figure out how to legally drive the car to the dyno and I got it all worked out this week. So I went to the dyno today. Last week it ran perfect, but it started hesitating very bad yesterday so I was worried all was gonna fail. The fuel system was good, and the timing was set correctly at 15 degrees. I didn't knew anymore where to start. So I went with some of the basics, refitted a poorly grounded harness cable and cleaned the AFM and CAS harnesses. Then, all of a sudden it pulled correctly again.

 

Now I haven't driven this car in anger before the manifold swap, but it does feel like the standard mapping is not suited to this manifold. If I quickly depress the throttle after a gear shift, there's no response. It also feels somewhat nervous and sensitive to throttle changes, a bit like my brother's Gti-r with the OEM ITB setup. This system really needs a map 'written' for it.

 

Anyway, on the dyno all went well. The car pulled 263hp/349nm uncorrected at the rear wheels, on a warm day (29 degrees C) and the coldpipes from the intercoolers got very hot as the 2 coolers they had were not that powerful. I estimate the inlet temp was around 45 degrees C. During the other pulls the power went down as the engine heated up even worse and the operator couldn't get a good pulse from the ignition system, the output was therefore measured in speed not rpm's.

 

The blue line is the first pull. The torque values are incorrect, they had some trouble getting the dyno system to correctly convert. Explains the weird 800+nm spike. Realistically, it's about 350nm at the wheels.

 

 

 

Now I'm not directly converting the car back to stock, there's another type of manifold that I want to try on the dyno. Roughly the same as this one, but with the stock TB's. Will make a different topic for that.

How cool would this be in carbon fibre ....stunning work mate

In theory, the plenum chambers can be made from carbon fibre. However, the chambers will have to be bolted to the aluminum flanges were the velocity stacks sit on. Highly complicated to fabricate for just 1kg weight reduction

:biggrin:Thats some fantastic work and dedication there, its incredible how much work has gone into that fabrication, please do keep us updated :biggrin:

Absolutely superb :)