Jump to content
HybridZ

NAPS L28 Intake Manifold with twin butterfly TB


NZeder

Recommended Posts

I have purchased an L28 from an import engine supplier here in New Zealand. The engine I received did not come from a ZX but I think maybe a Nissan Skyline or Gloria as the mounts don't look like anything I have seen before. The block is an F54 the head is an N42 but it is the intake manifold I would like to know more about. So has anyone on this site seen this type of EFI intake before and know if I should keep/use this?

 

The manifold has "NAPS Computer System" cast on the top of it (I will attempt to link pic from my gallery)

http://album.hybridz.org/data/500/11058L28-intake-manifold-loaded.jpg

http://album.hybridz.org/data/500/11058L28-intake-manifold-stripped.jpg

http://album.hybridz.org/data/500/11058L28-intake-manifold-TB-connection-messurements.jpg

http://album.hybridz.org/data/500/11058L28-TB-2-butterflies-with-messurements.jpg

 

The throttlebody has a twin butterfly setup one is 38mm dia the other is 42mm. The input into the TB is 65mm and the input into the plenum chamber is 80mm high by 40mm wide.

 

I have read on this site and many others that a recommended EFI upgrade it to replace the TB with a 60mm unit from MSA or the 240sx TB. My question is given this NAPS manifold is different what are your recommendations? My car is a RHD 1977 260z that has those bad carbs. I am thinking of going EFI with aftermarket ECU. This is way I purchased an L28 ensuring it was a F54 block (as these come with EFI etc). This engine also has a crank trigger ignition fitted standard - good? bad? replace?

http://album.hybridz.org/data/500/11058L28-crank-trigger.jpg

 

Next step is to do a CR test and maybe pull the head, clean/crack-test/port-polish, rebuild bottom end if needed (ie change from dish to flat-top pistons etc)

 

So does anyone have any ideas about if I should use this NAPS EFI manifold (thinking I will as I don't have any others - unless I purchase a different manifold - DCOE Throttlebodies are an option in the future but $$ will be the killer here in NZ)

 

I have also seen/read about guys using different fuel rails - I would like to have my engine setup with a hidden loom and a tidier fuel rail - what is the solution (ie replace the injectors + fuel rail or modify the standard injectors + new fuel rail or just a new custom fuel rail)

 

Cheers

Mike

Link to comment
Share on other sites

Not sure but I think there might have been L28E powered Skylines in South Africa. ie before the RB engines were every produced. In NZ we knew of the 240K GT (70's vintage) these were also called a Skyline in other markets, powered by the L24.

 

Anyway I think the engine is from a Nissan 430 Gloria/Laurel/Cedric/280C of the 80's (I think even the Nissan Leopard used the L28E although most I have seen have the LD28 fitted from factory). These produce the same HP as the n/a 280zx of the same era ie 180hp net or about 135rwhp (these are figures I found on a number of Japanese sites). Not much info on these Nissan Sedan L28E powered cars can be found anywhere?

 

I know that NAPS made/developed the high performance crossflow heads for the 4 cylinder L series engines (some called NAPS-Z or LZ14 or LZ20B) so I guess I am hoping what I have is a performance factory intake manifold....but I am not sure so I am hoping some on this site might know.....

Link to comment
Share on other sites

The NAPS manifold is a later japanese domestic market manifold - they are supposed to flow better than the 'stock' manifolds, and were the preferred manifolds for Production Rally Car (PRC) rallying. It should have a two similar sized butterflies unlike the other style with large/small. I think I still have one under my house somewhere....

 

As for the Skyline/RB comment, the first skyline with an RB motor was (I think) the HR31, the R30/R31 etc came with L series engines, in either L24/L24E or L20A Turbo.

Link to comment
Share on other sites

mj, thanks for the info re the NAPS JDM manifold the butterflies are very simular in size almost to close to pick with my crude measurement (a compass to get the diameter of the butterfly and a ruler). I will use this manifold and de-burr the rough casting, port match to the head etc. Re my fuel rail question I did a search late last night and found lots of info and comments on the JSK Fuel rails so I will be looking into one of these units.

 

Cheers

Mike

Link to comment
Share on other sites

Not seen that before, As far as I knew though the Skylines only came with RB series engines. Might want to try over at [url']www.skylinesdownunder.co.nz[/url]

 

 

HR30 skylines came out with L series engines

DR30 skylines came out with FG series engines

xx31+ skylines came out with RB series engines

 

note that my PNV HR30 came with a L20ET

Link to comment
Share on other sites

About ten years ago, I purchased an L28 from a Japanese engine importer that had that manifold and was an F54 flat-top/P90a without the hydro lifters. I tried to use it after swapping out the cam (Crane 280) for one that I had in a previous FI L28 with the standard intake manifold. After getting it running, I can tell you that the motor would fall flat on its face after 5500 rpm's, whereas before it would pull to about 6500-7000rpm's. I put the standard manifold back on ( with the Mercedes 65mm TB) and there was a huge difference. I don't know how it would work with a turbo, but my guess would be that the results would be the same. A restriction is a restriction.

Remember that "NAPS" stands for "Nissan Anti Pollution System", or Nissan Anti Performance System!! :)

Just my .02

 

Aaron

Link to comment
Share on other sites

So have you thought you might want to sell it?

 

I've got both turbo and N/A manifolds I could trade also.

 

hmmm a trade is out of the question - shipping from NZ 2 TX will be about $100 USD at least so that kills the trade right there (and this does not include shipping from Tx 2 NZ). Plus I think I will use it for now if it does not perform I will locate another EFI intake manifold locally or go triples as I already have a triple DCOE manifold (no carbs) or triple TB on the DCOE manifold. The cost of triple throttle bodies here in NZ is about $1300 - $1800 USD and for that I might get a custom made manifold (or modify the NAPS unit I have to flow better). This all assumes the NAPS manifold does not REV as "aarang" states.

 

I will be pulling the head off the block shortly to check if all is OK. If the block has dish pistons I will replace with flat-tops to up the CR to approx 10:1 and do the usually rebuild stuff - polish, shot-peen, balance etc.

 

This will be my first engine rebuild so I am looking forward to learning a lot of new stuff. Sites like this help with the knowledge amongst members and existing treads/discussions.

 

I will also be adding to my tool box in the process if there are any special tools etc that are recommended please let me know - ie a 12mm ring/open spanner that is no more than x thick or that is longer than y will help with w.

 

Cheers

Mike

Link to comment
Share on other sites

hmmm a trade is out of the question - shipping from NZ 2 TX will be about $100 USD at least so that kills the trade right there (and this does not include shipping from Tx 2 NZ). Plus I think I will use it for now if it does not perform I will locate another EFI intake manifold

 

 

Well It was just a thought. I wasn't sure about the shipping. I'm not surprised to hear that it's so costly. That manifold it pretty cool.

Link to comment
Share on other sites

George - re the dish vs flat-tops see the following site for info on the L6 series of engines, blocks/eads.

http://www.geocities.com/zgarage2001/z.html

This site talks about the US specs engines (head/block combos). Here in NZ we get all kinds mostly JDM combos or Australian combos so most L28 with F54 blocks have the N42 head (different anti-pollution laws in Japan/Australian and none here in NZ - I believe this is about to change this year with the new exhaust law). And therefore due to this F54/N42 combo have the dish pistons to lower the CR to 8.3:1. If this block/head combo has flat-tops CR is more likely to be 9.8:1.

Link to comment
Share on other sites

RB30-ZED, thanks for the recommendation re the 65mm TB I will look into this when most engineering shops open back up after xmas/new years break.

 

Anybody have any recommendations re the polishing of the EFI intake manifold? What is a good polishing compound to remove most of the casting pits etc. Once I have the manifold looking good I will have it clear anodized to keep it looking good.

Link to comment
Share on other sites

  • 4 years later...
HR30 skylines came out with L series engines

DR30 skylines came out with FG series engines

xx31+ skylines came out with RB series engines

 

note that my PNV HR30 came with a L20ET

 

I was 1 of the founding 4 members of Skylinesdownunder & I have had several HR30 Skylines and all of mine have had the L20et or just the L20e

except for a 5 door hatch that I aquired which had a LD28 in it,

The DR30's came out with the FJ20DE and FJ20DET depending on the year and as metioned above the R31 came out with the RB20E an RB30E Mill in them.

 

In saying that I have also owned 2 Z cars also and the 280ZX I Had had the same twin choke throttlebody on it's intake but it wasn't a NAPS manifold as you have pictured above, and the fairlady had the same as the Skyline on it's L20E, which can be changed to 1 if an RB20 with a little modification to the RB20 throttlebody (they open the opposite way):)

Link to comment
Share on other sites

I was 1 of the founding 4 members of Skylinesdownunder & I have had several HR30 Skylines and all of mine have had the L20et or just the L20e

except for a 5 door hatch that I aquired which had a LD28 in it,

The DR30's came out with the FJ20DE and FJ20DET depending on the year and as metioned above the R31 came out with the RB20E an RB30E Mill in them.

 

In saying that I have also owned 2 Z cars also and the 280ZX I Had had the same twin choke throttlebody on it's intake but it wasn't a NAPS manifold as you have pictured above, and the fairlady had the same as the Skyline on it's L20E, which can be changed to 1 if an RB20 with a little modification to the RB20 throttlebody (they open the opposite way):)

 

Got anymore info pics ect on this r30 your building, id love to see it

Link to comment
Share on other sites

Hi there Nick, Bryan Here, Well my r30 looks alot like yours,hahaha, well it's red and black anyhow and is along way from anywhere at the moment but at least I got another 1 and thats got to be a good thing.

 

Am still tearing it down to repair and rebuild it,it's in a very sad state at the minute lots of rust to fix and the stock motor aint a runner in any stretch of the imagination, so hence the L32et going into it:flamedevi:burnout:

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...