sneakpeak ITB intake fab job

[kolonelklink]

Hey guys,

Since everyone was so kind and helpful to me with an earlier post seeking

advice on valvetrain components I decided to post the first pictures of my

ITB manifold fabrication in process

Any advice comments and suggestions are highly appreciated but keep in

mind this is just an early mock up and that further work is ongoing.

I'll be very interested to see if anyone can recognise where the throttle

bodies came from

 

Cheers!,

Pete

 

 

[nat0_240_chevZ]

runners too short, i think

nat0

[waxhead]

I would say by the look of them they are off an r1 yamaha or some other large displacement motorbike

[garvice]

I think if you swap 3 and 4 they will look more in proportion.

You can always put the extra runner length between the throttle bodies and the plenum. Keep it like you have it so the injectors are nice and close to the head.

[NZeder]

Keep it like you have it so the injectors are nice and close to the head.

Only if economy/emission's is your goal this is why OEM do it - for performance move them further away

[nizm0zed]

i used to have a chair like that, it was blue and decided it wanted to break while i was standing on it changing a lightbulb.....

 

 

 

Anyways, back on topic.

Looks good. If it were me, i would space the throttles back off the flange about an inch or two, depending on the plenum you plan on running and hom much available space you have.

the slightly longer runners would help to promote a little more torque from the motor, and the injector being further away will help it atomise and make better power at high RPM.

Bear in mind, the further you move the injector away from the inlet valve the more likely you are to introduce rough running at idle and low RPM's, as the fuel tends to wet down the runner walls and pool in the bottom of the runner.

If its very minor, increasing the size of the injectors and going to sequential fire often fixes it.

Not a cheap way to do it though.

[kolonelklink]

I would say by the look of them they are off an r1 yamaha or some other large displacement motorbike

I'd considered it but guess again... I turned over these for nothing and they worked out to be just the ticket. Think more wheels and older.

 

 

Bear in mind, the further you move the injector away from the inlet valve the more likely you are to introduce rough running at idle and low RPM's, as the fuel tends to wet down the runner walls and pool in the bottom of the runner.

Because of the way the runner and head ports are shaped there shouldnt be too much opportunity for pooling except behind the intake valve so touch wood this shouldnt be too much of an issue given some careful portmatching... I think

 

Only if economy/emission's is your goal this is why OEM do it - for performance move them further away

Correct... this setup is not in any eventuality intended to be economy/emissions. As a whole the direction of the build indicates a "screamer" application.

 

Regarding the runner length - we recognised early on that using these TB's the throttles would be very close to the head... adding additional length post TB would be preferable however the fabrication involved would be significantly more extensive... I would love some more discussion on this point - our intention was to add extra length via sleaving the plenum end of the runners with velocity stacks... how much detriment to flow do you guys think this approach might cause when compared to adding the same length post-TB?

The runnners are taperred at 2.5 degrees.

[NZeder]

Cool tapered bores + for air speed ie high RPM. So I am getting a feel for this build now

 

So have you thought about have an adjustable ram tube/trumpet aka Mazda's 1992 le manns winning R26B engine in the 787B

 

Use a stepper motor to change the runner length at different RPM

[kolonelklink]

So have you thought about have an adjustable ram tube/trumpet aka mazda's 1992 le manns winning R26B engine in the 787B

 

Use a stepper motor to change the runner length at different RPM

 

Oh yeah... definately. =)

[RB30X]

i used to have a chair like that, it was blue and decided it wanted to break while i was standing on it changing a lightbulb.....

 

;D

 

Love your work mate. Any pics inside the throttles, where the blades are etc. Honestly, I'd weld those to a DCOE flange and get a cheap DCOE manifold to put in between. This will give you the increased length between the injector and intake valve. You thought about what will drive this system yet?

[kolonelklink]

Love your work mate. Any pics inside the throttles, where the blades are etc. Honestly, I'd weld those to a DCOE flange and get a cheap DCOE manifold to put in between. This will give you the increased length between the injector and intake valve. You thought about what will drive this system yet?

Everything is at machining atm so no photos sorry However, when everything is mocked up on the head and you look down the barrels you can see straight past the valve seat into the combustion chamber ... I'll take photos next week when i have everything back home.

Honestly i'm tempted to leave the length as is, i like the straight shot and the DCOE manifold would affect that and i'd have to do some milling and redrilling on the DCOE manifold to maintain the downward loading angle acheived with the current setup.

the TBs were actually designed for an engine of similar displacemnt to the L-series with an extra few cm of lenght incorporated into the plenum...

I'm still curious about the velocity stack idea?

[Zedman240®]

I remember when people used to machine their Weber manifolds on an angle where it bolts to the head to try and get a straight line from the trumpet into the cylinder head. I'd leave your setup as it is and try it. You'll have fun with the fuel rail and linkages!

[nizm0zed]

Because of the way the runner and head ports are shaped there shouldnt be too much opportunity for pooling except behind the intake valve so touch wood this shouldnt be too much of an issue given some careful portmatching... I think

 

Sounds like you have a pretty firm grasp on the idea and theory behind it, but handy tip, fuel wetting the walls of the runners can be considered as pooling.

Instead of the fuel being tiny atomised drops, they coalesce together into larger non-atomised drops that stick to the runner walls.

They still burn, but not as controlled as a tiny droplet.

I doubt your going to have an issue with it though.

 

 

waiting on pics, this shoud be pretty good

[DatZed]

Looks great, but am I the only one thinking 12 injectors? We picked up 18% peak power with the last eight injector SR20 we built. You will need an M800 or SM4 to run it which is a pain, but it's worth the extra effort.

I wouldn't add any length between the butterfly's and valve heads, a tapered intake tract from a nicely made bellmouth would be the go. In the past I have got good results from total intake lengths around 355mm. You can make a slipper fitting for the ramp tube with some silicone hose so that you can play with different ram tube lengths on the dyno.

Although your intake flow is going to be good, what are you going to do about the exhaust? Trying to get anywhere near 170cfm from the exhaust side of a z head is hard work. I have been toying with the idea of removing the liners from an N47 head and putting a tounge in like is done with Clevland heads.

Anyway, nice work what ecu are you running?

[NZeder]

In the past I have got good results from total intake lengths around 355mm.

Does that include the head ie from the valve to the end of the trumpets? Or is that just from the head mounting face to the end of the trumpets?

 

As you stated it is the exhaust that needs the most work from the L6 heads.

[kolonelklink]

Looks great, but am I the only one thinking 12 injectors? We picked up 18% peak power with the last eight injector SR20 we built. You will need an M800 or SM4 to run it which is a pain, but it's worth the extra effort.

I wouldn't add any length between the butterfly's and valve heads, a tapered intake tract from a nicely made bellmouth would be the go. In the past I have got good results from total intake lengths around 355mm. You can make a slipper fitting for the ramp tube with some silicone hose so that you can play with different ram tube lengths on the dyno.

Although your intake flow is going to be good, what are you going to do about the exhaust? Trying to get anywhere near 170cfm from the exhaust side of a z head is hard work. I have been toying with the idea of removing the liners from an N47 head and putting a tounge in like is done with Clevland heads.

Anyway, nice work what ecu are you running?

 

Arg!!! this is why I was so tentative to post anything looking like a build blog... everyone always wants more info and progress!!!

Thanks for the encouragement guys; I havent got a huge lump of time atm - this is a weekend project for me and its a whole vehicle thing atm so progress is understandably slow as a whole (but still there!!)

Some more machining has been done to clean things up and get better fit. I will not be adding lenth between the butterflies and experiment with velocity stacks.

Previously I have run MSnS-E but am open to suggestions (please consider budget and feasability constraints guys!!!) I was certain injector staging was a doable option with that setup but have never needed to attempt it... given the higher rpm goals for this build i would consider putting injectors in front of the bellmouths via the plenum. This can be added after i get some O2 data and dyno time methinks.

Exhaust.... I totally agree and I'm not even started on that yet, I'm hesitant to comment too much due to the unknown area that exists in future budget and timing constraints (I'm doing almost 50 hours of classes alone a week at the moment)... I've considered upsizing the exaust valves but i suspect the greatest bang-for-buck gains can be made from aggressive portwork and a decent-flowing home-fabbed steam-pipe turbo manifold. (no i havent had the time to start on that, nor will I untill this is completed)

i'll try to post some pictures of the cylinder head when it gets back from machining on the weekend. At current the cam i have has a .490 lift and 248 duration 'though i suspect that by the time the build is complete this will be "too conservative"... we'll see.

An n47 might be a cool move. I went with the carved mr30 e88 for the longer valves (compared with the p90) and my inability to afford a good cont. japspec welded n42 or source the elusive "mn47" domestically... The culture over there really seems to indicate the n42 as the way to go with really aggressive port and valve modification and they do have the numbers to back it up. Personally I encourage you to try the tounge idea, partly from selfish curiosity and partly because it seems novel and could yeild some ponies for you and add to the volume of L-series knowledge... but I digress

 

Thank you for your input and the slipper-fitting tip. I'm sorry I dont have the numbers and figures at my disposal to answer your questions concisely- as a scientist that frustrates me, I cannot predict the outcome of the build untill dyno day which is very far off but if nothing else the manifold alone will be an awesome conversation peice!! consider this build "an experiment" and I am very grateful and willing to take on any further suggestions thoughts and ideas

 

-pete

[DatZed]

Hi Komendant, I've never done any intake tuning on a turbo engine. There's an awesome article on Hybrid Z about turbo intake dynamics from some guys with too much time and money. They modeled it with Fluid Works and come up with a pretty impressive, but complicated setup.

Nzeder, that length is from the bellmouth to the valve seat.

I am going to the wreckers this weekend to find an N47, I'll let you know how I go. I have an N42 if you want it, owes me $50.

[kolonelklink]

hmmm... i dont have one of those at the moment... tempting impulse buy  :-\

Yes i've read that article before.. great thread . also keep your eyes peeled on the l6 section, i'm about to dump some auto-porn from a visit to the nissan engine museum in yokohama.

Bunch of stuff happening this weekend; finally finished rail repairs and put wheels and suspension on the cedric w0000 big moment cylinder head came back from welding and machining.. it loooks purdy, i'll post some photos in the next few days once i find a new camera. As a result not too much happening on the ITB front, i'll try to find some time for it tomorrow. Maybe I should put up a build thread so everyone can criticize my dodgey worksmanship??

 

DatZed, are you in sydney at all? Postage on that head would rival cost i expect? let me know how the n47 hunt goes? i'm very curious about that one.

 

-pete

[DatZed]

Tracked down an N47 yesterday for $80. I have ditched everything exept the casting itself. The finish on the liners is pretty average, but I can see some potential for sleeving the ex ports. I'll get it hot tanked to get the vegimite out and post some pics. Interestingly the ex ports themselves are nearly 40mm, but the id of the liner is only 28mmish and not round at all. Nice chamber though, better than an E88 and pretty similar to the A87 found on the 4 cyl. My 38mm ex valves are going to be a very tight fit, good thing I am using an 88mm bore otherwise they wouldn't fit without off set valve guides.

Sorry mate, I'm in Melbourne. It would take quite a few stamps to get it to Sydney.

[ozconnection]

Love the look of what you've done so far Pete.

 

Do I get any prizes for "guessing" those throttle bodies? I won't spoil it for everyone 

 

I'm not convinced that there would be any pooling of fuel in the area of the injectors or the immediate runner ports. The gas velocity in that region is high and there is sufficient heat from the exhaust system to vaporize the fuel. I'm also reminded about the situation of those boys running triple carbs and how this may be a little off the mark but there are enough similarities to compare the two. Do they suffer from fuel pooling?

 

Good to hear that your coupe is back together. AND I can't wait to see how your engine performs with those ITB's.

 

Cheers. 

 

[kolonelklink]

Do I get any prizes for "guessing" those throttle bodies? I won't spoil it for everyone  ....

 

...I'm not convinced that there would be any pooling of fuel in the area of the injectors or the immediate runner ports...

 

A) no way anyone guesses it... without knowing i wouldnt have though in a million years they'd be making these "over there" "in those days".

B) Yeah, maybe i'm being a bit callus but really think its going to be a non-issue, the injectors are only moved back a few CM and the adjusted angle places the spray pattern dead-on with the apex of the short side radius... as long as the fuel pressure is sufficient to atomize, i can't see any significant pooling occuring in that short period.

 

Regarding triple carbs - I nearly completely agree excepting that I'm using polished ports/manifold and some carb-users prefer to leave these textured? However, from the stroker builds using mikunis i've seen on japanese threads most have highly ported and polished ports and manifolds... i wonder how they idle?? (who cares if they go "vwroooom!!" really loud at 8krpm...)

 

 

DatZed - given the n47 contribution perhaps we should rename this thread "2010 L6 R&D" :P

 

*small progress update* I started grinding the flanges to size today... took me all my time just to do one... this is gonna take a while. still have to do the other 6 and grind the ports out to the 37x 38.5mm oval flange... ugh. on the plus side... for any of you suckers paying $15 a pop for drain-o, you can make it using $2 worth of sodium hydroxide crystals and mixing it with aluminium shavings; just saved you 13 bucks

 

 

Cheers 'gents,

-Pete

[kolonelklink]

Quick update:

This is one of the 2bbl flanges that will hold the runners to the head. I did some reshaping and then placed it behind an untouched one so you can see how much cross sectional area i'm gaining and where (all from the top). The diameter is 37mm but to get to the height i wanted from the cylinder head port is had to go up to ~40mm max oval shape... as a result im considering filling the extra few mill at the base of the port using an epoxy... dont want to weld the short side. I dont  feel i require anti reversion on a minimal overlap turbo grind cam btw (mark.. ) I can take a photo of this later.

 

this is a quicky of the head im using - modified late model e88... i still need to do a bit more CC reshaping and unshrouding plus volume balance the head, but it's coming together very nicely

I've decided to put together a home flow bench and calibrate it to spit out some ballpark flow numbers for me and y'all so keep tuned for that.

 

This is the 260c coupe being put together at the same time... it took a massive front impact and we had to swap rails all the way from the front right (see the "kink"... need to hide that ) all the way back under the driver seat. in these cars thats a single peice to that far back so it was the safest approach... though alot of work ... just goes to show cars *can* come back from the dead

 

This is the donor.. you can see how extensive the transplant was... all good now though!! it seemed a tragedy to trash an okay car to save a wreck but the coupes of this year were WAY rare and I may never catch another one again (my vin has 3 significant figures:P) plus i'd feel terrible taking one out of the world *ghost car hauntings!!!*

 

 

hope that helps show how things are going and the direction of the build a bit more... always pleased to hear feedback!!!

 

 

Cheers,

-pete

 

[NZeder]

Nice a 260c coupe. There was a 260c wagon for sale here in NZ recently (one of about 4-6 NZ new unit) that would be cool to own. The even have a key by one of the back windows then you put the key and turn it the window goes down electrically.

[kolonelklink]

yeah they are pretty groovey luxo-barges... the 330 coupe suprising has quite a american-muscle inspired streak in the design -along the same lines of the laurel and 240k coupes... i guess thats why all three are fairly popular in bosozuku car circles. I think it's going ot be a unique and cool build...

 

back on manifold and engine though... If anyone has a set of l26/l24 flattop pistons: what is the crown thickness, is there an option for a maximum-crown thickness for this bore? (aftermarket)? I'm looking at options for piston/combustion-chamber semi-dish machining.

I should have some progress on the ITB's soon.. need to tap the vacuum balance tube holes and add fittings before welding can commence... watch this space!!!

 

-pete