custom VH45 inlet manifold

[ultrapulse]

Just got it back from being pro coated. Will update pics in the future with injectors and fuel rails etc. The big hole in the bottom is where a 50mm front plug sits. This is incase of a blowout. I wasnt going to worry but a couple of guys i spoke to recommended this. The other hole underneath is for the idle control valve off the std setup. This was another thing a mate didnt use, however I want mine to idle good when hot or cold. He says his idles a little higher when warm, however mine is mainly for street car use. This mani takes the std vh throttlebody, however I have flowed the butterfly shaft to increase the flow...just in case. The 8 x std rx7 550cc injectors flow around 850-900hp with the fuel pressure I'll be running, so should do the job. If not they are not too much $$ to replace these days with bigger.

[ultrapulse]

BTW, this was an awful lot of work to make. One reason was to make most of it fit under the bonnet of my car. I have succeeeded but will need to make a small bulge near the front as it appears to not quite clear near the front only. Another reason so that I can use a variety of common top feed injectors, along with making the engine more easy to work on and uncluttering the whole top of the engine. The std manifold has a couple of sharp bends near the end of its travel to get the injector to 'look' at the inlet valves which I thought i coulkd improve on. The other thing is that since I'm supercharging, there arent the same strict rules with tuned length runners. All other parameters I have done the best I can. I think even though the std inlet is an oversized ugly piece of woek, it still doesnt look too bad for most applications in my view. I will dig up the sizes I used for the runners and plenum, as I cant remember all since i made it a while ago now. I think the plenum is approx 3.8litres. I think I went engine capacity(5.2) divide by 2, plus 40% to get power lower down, ie 3grand. Al will be revealed when get it going as to how well it works.U have to admint it looks (or will look) a bit prettier than the factory one. I have approx 10-11" length from valve to plenum. One guy I spoke to said "perfect" however I beg to differ. When nissan made the z32 tt 300zx, heaps went into the tuned length trials (with good results), however the same era godzilla received no tuned length intake runners...so go fugure! I do know that the z32 has more lower torque than the r32, which I suspect may be due to more than the 400cc more capacity. I could have made the runners longer, but all gets too long, and I was critical about the injector aiming straight at the inlet valve which is a hurdle for anyone buiding a mani for these engines.
Modified by ultrapulse at 3:40 PM 11/23/2006

[Mettler]

Beautiful!

Good work man. How did you shape the runners?

[ultrapulse]

Another mish... I couldnt buy any thick wall ali tube, noone sold it locally over about 3mm. I then tracked down a guy who does bullbars and nudgebars, which is approx 4.5-5mm thick from memory. So yeah I got him to bend up 4 x 2.5" bends, chopped them in half to get approx length, then cut down length-ways as 2.5" was too bigger internal sufrace area for each runner. Also made them flare slightly from top to bottom. THEN had to cut again on the underside(or inside radius) to get the tig torch in to weld the inside injector boss area. What a job. However I could do it again a lot more quickly (but dont want to:). I will post a couple of progress pics to save me woody woodpecker typing.I wonder what it would take to get a cast made up off it?

[slownslurious]

the curiousity in me wants to know why you went to such great lenghts in spacing out the plenum from the heads if youre going with forced induction?

[John Dixon]

Nice work!You should look at putting trumpets in the box where the runners enter, or at least radiusing them. The entry losses are huge for a square entry.

[Q45tech]

Just using simple ratios the 11" vs 18" runner will tune 63%{+- taper and entry cone] higher than the 4,000 rpm oem torque peak. 2nd Helmholtz resonation

Always nice to have the 561cc volume of the cylinder in the runner and valve port in head.............nice to add enough volume to offset the fuel volume........................but then again you can reduce based on boost [one specific rpm and one specific boost [density]

[ultrapulse]

"the curiousity in me wants to know why you went to such great lenghts in spacing out the plenum from the heads if youre going with forced induction?"

By trying to get the injector stream inline with the flow towards the back of the valve & not being in the way of the runner ended up this way (hard to explain). Also the poxy oem water pump/thermostat housing sticks up at the front of the engine, so couldnt go superlow there. I want to retain all factory simple stuff like oem waterpump. Another thing from memory is the height of the injectors and fuel rails end up being nearly as high making any other reductions pointless. The throttle is on a lean to reduce the front as close to the waterpump/thermostat housing as i can, as this is the area that may/maynot touch the bonnet.

"Nice work!You should look at putting trumpets in the box where the runners enter, or at least radiusing them. The entry losses are huge for a square entry."

Yes believe me they are radiused. I actually slightly enlarged the entry points of the runners and radiused them. Though u may not be able to see from the pics they arent bad.

I will have to think about what q45tech said.... Another thing, It may look like a highrise manifold, but by the time u fit the huge rocker covers, it soon shrinks down and looks beaut!
Modified by ultrapulse at 1:46 PM 11/24/2006

[SSDwellah]

I apologize if I missed any previous context, but which car is this setup going into? I am surprised and impressed that you cleared the hood.

[ultrapulse]

Hey not a problem, I'm fitting a vh45 to a z32 300zx. Is touch and go whether it clears near the front. I have however got hold of a fibreglass bonnet to modify if I dont have any joy with the factory bonnet.

[Jeff Williams]

Great looking work! There are a lot of hours in that thing.

[SSDwellah]

ultrapulse

That is awesome! I bought a Z32 NA A/T on the cheap and I am looking to do a VH45 swap as well. I hate this slushbox, but most M/T Z32's with the same mileage around here were about double the price. The one thing I don't like about the VH was the intake manifold and having to cut the hood so if you ever wanted to mass produce these in some way I would be all over it. How did you mounts come out? Is the engine sitting too high/low/forewards/backwards? I suppose with some mount adjustments, if there's any room left to play, you could clear your custom IM.

Not to thread hijack but on a side-note I am looking to get mounts somewhere for this application. Are you planning on making them or do you have any tips (stock nissan x-members or mounts that are a good/close fit)?

Thanks

[ultrapulse]

Great looking work! There are a lot of hours in that thing.

Yes, estimate the approx time and multiply it by 4.I would be really keen on getting a mould as I'm in no rush to make another one!

"SSDwellah""I am looking to get mounts somewhere for this application. Are you planning on making them or do you have any tips (stock nissan x-members or mounts that are a good/close fit)?"

I am using a t56 transmission, and the new crossmember/z32 crossmember wont be too far off, but definitely no direct bolt up. The engine sits a little too high due to the t56 front section hitting part of the tunnel. A std z32 box should be fine as it has a smaller "height" near the front. Also the z32 rack sits way high making lowering the motor difficult to offset this. A combination of the z32 engine mounts and ali brackets get closer to the subframe but still nothing really close. Wil update as I'm doing this now. Cheers.

[SSDwellah]

I forgot to mention how exquisite the manifold looks. Excellent job and nice touch with the nissan emblem! Did you find a metal one or did you just stick on one of the plastic decorative trim emblems from a bumper (like the S13 240SX one for example)?

Also where are you located? I am trying to figure out if you will have RHD clearance issues different than the LHD issues in the states.

EDIT: Nevermind about the emblem. At a second glance, it clearly looks welded on so I'll assume its metal.
Modified by SSDwellah at 7:27 PM 11/28/2006

[ultrapulse]

I dont see any differences with the steering shaft either LHD or Right, as both are in the way like always! However I have made a remote clutch master cyl setup real cheap, check out this thread.http://www.nz300zx.org/phpBB2/viewtopic.php?t=1714Not many pics, but the TT zed clutch uses a small booster on the inside of the engine bay with an ordinary master cyl outside. This one was $5 from a wrecker. Its off a p11 (1997 approx) Nissan Primera. Dont know if they have them in the US, but they are a small 4door front drive with sr18's and sr20 engines. They are the same bore size but due to a huge recessed firewall mount the resevoir separate. Instead of the booster vacuum hose poking thru, its now the reservoir hose. The hydraulic line pops thru just below it with a chassis type budy fitting. The good thing is theres no real mods to anything in that area, and have no clutch mastercyl in the way. All just bolts straight it. As far as the brake booster I used a Nissan 2.5T R33 skyline booster. Smaller diameter=more room without hitting right rocker cover, though being towards the outer side may be avantageous(wow big word) for a RHD car as your booster will be closer to the engine bay.One last thing. I welded a 5mm thick ali emblem I hacksawed up out to the mani top, die ground the weld to make it look 'cast', then am planning on gluing the plastic crome emblem u see in the other pic. Wow thats enough typing.

[gdz1la]

any small fwd nissan booster will fit, niceley, i think mine was a pulsar,

i had to modify my clutch cyl on my gtr with i rb30det it, i just removed the booster, re drilled the cyl holes to suit a silvia m/s and adjustated the pedal to suit, that should give you enough clearance, are people still doing up z32s in nz these days?

[sinfiniti]

ULTRAPULSE, you arent by any chance a welder by trade are you?

[ultrapulse]

I dont know whether this is a cheeky question or not, but the answer is NO. And to explain some of the dodgy welding on the underside of the mani, well I did it in situ...real fun that was....BTW I'm a sparky by trade but always tinkering...Just finished engine mounts today...sweet!

[sinfiniti]

****! good work mate. so did you use a mig or a tig for the alloy welding?... it looks too good to be done by a mig.again very impressed, and im not easily impressed!

[BuickturboV6]

Beautiful manifold! This is exactly what I was looking for as apposed to the twin throttle body McLaren'esque intake manifolds that I've seen for the VH45.

Was the running length selected because you're looking for more torque?

[AZhitman]

Gorgeous!!!!

This is simply amazing, thanks for the pics, ultrapulse!!!

[ultrapulse]

Was the running length selected because you're looking for more torque?

No, its actually shorter than stock, and made to fit under the bonnet, along with a nice injector angle towards the valves. A 'small' tradeoff (if u could call it that) is that it looks different, infact gives me more room along the whole top of the engine. I have always complained about the z32 engine especially that horrible inlet which crawls over the entire engine bay.I calculated the plenum to be good around 3000rpm, and the runners apparently tuned for about 6,500rpm according to (q45tech). Though since I'm blowing the stuff in this tuning isnt really important. I just wanted a reasonable plenum to 'equalise' each runner along with giving the map sensor a better less pulsy signal. Its all about compromise, so give me simple, light and accessible anyday over possibly a few more horsepower.

[riu]

how would this plenum do without forced induction?

[ultrapulse]

Should be good, though is tuned higher than the factory one. Will report back once I get it going without the blower hooked up initially.

[SSDwellah]

ultrapulse,

Have you considered the dual plenum setup on the VG30DE? Nissan was able to get the runner length they wanted by interleaving the runners and locating each plenum above its opposing cylinder head. I can't find the paper now, but I remember reading a whitepaper or article that talked about how they'd tuned for the second harmonic of the valve closing (the first harmonic would require just too much length).

If you look at setups like the JGTC/SuperGT VQ30DETT Z's and Skylines or the R390 GT-1 they both seem to have dual runners made out of possible a composite plastic. It would probably be a lot cheaper to make and test as I am guessing it is juts plastic injection molding.

1. The first point is it seems they have isolated the banks plenums for a reason, not just marketing as these are not really production cars (or at least no mass market in the case of the R390). Have you considered going this way? If so, why did you decide against it?

2. It seems like the materials they use can take boost and heat. They are also presumably lighter than aluminum or sheet metal. Even the new generation VQ, the VQ35HR seems to have gone to plastic (and back to dual throttles again). Any comments or know any companies which can/are researching plastic auto parts like this?

In no way am I knocking your work: the plenum looks great. I am just curious what led to your thinking process. I definitely think there is more power to unlock in the Q45 intake and exhaust setups.

[ultrapulse]

Any comments welcome.Firstly the VG30DE(TT) i have in the shed. also have a tintop z32 tt manual so know plenty about these engines. I do know they got more torque out of this design, more for the NA by memory than a shorter inlet. Though in the same article it said that the R32 GTR had no tuned runner length, yet they still go pretty good (but are a bit revvy).

1.I think the separate plenums are just like that to get the runner length long. This was definitely the z32 design anyway. I dont believe there is any "secret" reason. I went against this design because of simplicity and space, especially when forced induction is involved and the lack of possible performance gained in doubling the length of things. Working on the z32 totally sucks!! Mainly because of its inlet manifold!

2.A guy at the local engine place has made a plastic mani. Is pretty ugly. However I believe that because newer plastics allow more heat and strength, along with an ever-increasing skyrocketing price of ali especially cast. One small possible benefit would be less heat-soak due to conduction from the heads, one thing I am looking into with coating mine. I know u cant touch the inlet on my z32 once youve been out for a hard drive. Cant do the intake charge any favours.

I admire your curiosity. My mani is quite light, approx 1/3 the weight of the z32 v6 one, and makes everything visible and accessible. I thought about the design for ages before I started, but just cant remember the reasons for everything. I believe unless there is a huge potential, dont go complex. Kinda like the KISS the americans talk about. Also take note that cars are not only performance items, like most businesses, they will be run by accountants as well (just like my work) so some things are done for that reason. Too much typing but I may have already said that I would normally trade a small amount of power for a tidy, simple, cheaper, less complicated design.

[SSDwellah]

Certainly your mani looks like it will be much less of a chore than the VG30DE for more routine tasks like changing the sparkplugs, and even lesser ones such as diagnosing injector issues. I agree the VG30DE's biggest downfall is that the IM gets in the way of a lot of things and must be removed for practically any service other than spark plugs (and even then you have to remove the balance tube).

All are good answers, thanks.
Modified by SSDwellah at 6:03 PM 10/11/2007

[hannibal]

This is quite impressive!

I'm really curious about intake manifold theory and design. You mentioned displacement divided by 2 for plenum volume and tuned lenghts for runners. Do you guys have any good links (or suggestions of books) where I could read more about these principles? Thanks!

[Aus450zx]

just bumping this back up, are there any pictures of how it sits with the coolant plumbing in place?

[CrazyTrance]

This is a great looking manifold, but an even older thread lol.