DIY ITB

[DreamZproject]

Yep searched, got as much info as possible, yup i know that its going to be a PITA and will be

expensive and not really worth it, but I'm exploring my options.

 

From my understanding to rig up pretty much any set up I would need a DCOE manifold and

have it slightly modified and have injector holes put in. (my estimate being $300 for the manni

and $200 for the modification?)

 

Option 1. Rb26 ITB - (I have seen a set on ebay for $300). Is it more complex than this as its very

much "one piece"?

 

Option 2. Toyota 4AGE ITB's - Buy 2 sets, take out half of one and sell it on. Will still need a

modified manifold. ($400 with the return for the other half of one.) These seem to be a lot

more "individual".

 

Option 3. http://www.racehead.com.au/?page_id=195

Brand new item (which seems pretty cheap) that claims it will bolt up to and DCOE/DHLA manni

At $700 odd its the most exxy, but that sounds cheap compared to alot of the other brand new

setups I've seen.

 

I want to run a proper/ mulitple proper air filters on this as i want an engine i don't have to

rebuild every 10K's.

 

Besides an aftermarket ECU (which I'd be going for anyway with efi), what other expenses

would i potentially be coming into that i have not forseen?

 

[KatoKid]

http://www.obxracingsports.com/products.php?pk=1458

[nizm0zed]

the RB26 ITB's dont have a provision for the injector mount, you'd need to get that added to the manifold.

Not that it would be hard, seeing as the manifold would have to be built from scratch...

 

Another option would be the throttles from a Suzuki Hayabusa (99 model was best i think?)

I have seen them in a custom application before, the person who did it said that once they were pulled apart, they stacked together like lego.

Obviously you would need to consider the injectors, whether they would flow for your application, or if they are able to be sized up?

would be pretty much the same as the Toyota ITB's though, so cost would dictate which path you take.

(If you wanted to keep it carbie you could acheive the same with carbie motorbike throttles, but why bother)

 

the bonus with using a DCOE style throttle body is you can use an off the shelf manifold and it looks sort of stock ish.

 

[C.A.R.]

The manifold & TB's are only half the required parts, Robbie.

No such thing as cheap aftermarket EFi conversions...

[Retro Z]

PM and ask Paul (Ledge) about the L-series  efi ITB's he said he is working on and going to release to the public. He mentioned it  a few months back but didnt go into detail about it as it was still on the drawing board i think.

[smugley]

http://www.ebay.com.au/itm/45mm-ITB-Throttle-body-6cyl-set-tps-DCOE-DHLA-weber-dellorto-efi-race-/271296935473?pt=AU_Car_Parts_Accessories&hash=item3f2a8eb631

http://www.ebay.com.au/itm/ITB-Throttle-body-weld-injector-fittings-6-cyl-efi-race-/271297120639?pt=AU_Car_Parts_Accessories&hash=item3f2a91897f

[luvemfast]

I was looking into this years ago myself, I've already got the RB26 ITB's and plenum.

But I have the bonus of being a toolmaker by trade and can build and machine all the extra bits myself.

If you had to pay someone? Would be better off just buying a second hand set off eBay.

[DreamZproject]

http://www.ebay.com.au/itm/45mm-ITB-Throttle-body-6cyl-set-tps-DCOE-DHLA-weber-dellorto-efi-race-/271296935473?pt=AU_Car_Parts_Accessories&hash=item3f2a8eb631

http://www.ebay.com.au/itm/ITB-Throttle-body-weld-injector-fittings-6-cyl-efi-race-/271297120639?pt=AU_Car_Parts_Accessories&hash=item3f2a91897f

 

Yah, these are the same items from option 3 (racehead). They seem to be fairly reasonable, considering most

kits seem as though they will cost around $2k...

With these it seems as though you could do it for a bit over a K...

 

Oh, and 40mm would be most suitable for a hot street tune right? much over that would be more suited to a

track car???

[d3c0y]

Yep searched, got as much info as possible, yup i know that its going to be a PITA and will be

expensive and not really worth it, but I'm exploring my options.

 

 

Besides an aftermarket ECU (which I'd be going for anyway with efi), what other expenses

would i potentially be coming into that i have not forseen?

 

 

 

Doesn't look like you have searched that much at all if all you think you need is an ECU a set of throttles and injectors.

[DreamZproject]

Well I've researched as much as i can with the limited knowledge i have.

I've never worked on an engine, but i have a large capacity and willingness to learn. It's fairly

hard to glean as much information needed from the internet without asking a few questions

which is why i posted this here, and wrote a preface saying that i have attempted to do all

the correct things before asking the question.

[strt260]

try this link:

 

http://www.viczcar.com/forum/index.php/topic,9230.0.html

 

I found it whilst searching for info on this topic some time ago. It mentions the considerations you may need make that go past the ITB's, injectors and computer. Hope this helps a bit.

 

Cheers.

[DreamZproject]

Thanks for that. I actually have no setup on the car at the moment as it is being 100% refurbished so i am at the point where

i want to decide which way to go so i can start to search for parts cheaply rather than just buy them brand new. i actualy have

most of the stock efi hardware so thats somewhat handy. The things i was talking about that I'd need for ITB's in on top of

what you'd need for efi, i left that as a given.

I would be scourcing parts mostly second hand and have to be patient about it anyway because my car is at LEAST a year off

being finsihed (most likely 3 years).

There was one point that Peter Mc wrote about that i didn't understand;

 

- Distributor cost with home and trigger around $600 - I have the 280zx distributor, I'm not sure what is needed here, and

why it is so expensive.

 

What i was after with the ITB setup is EFI not being restricted by the lame stock manifold, as well as some of the amazing sound

characteristics that you would get using carbs. Perhaps is there some sort of interim? (ie. aftermarket efi manifold?)

 

[strt260]

I think the Peter Mc unit is a refreshed and modified VL unit or similar, but not a standard stock 280zx unit. I'm sure someone can chime in on this aspect.

 

Know what you mean with chasing ITB's. It's really the ultimate set up - middle ground might be a custom manifold/plenum chamber and large throttle body? These can get expensive too..

[d3c0y]

You need to interface the crank signal with your ECU.

You can use the stock 280ZX distributor but there are better ways to do it. Obviously the ECU cant control anything to do with your ignition if you are just using a normal distributor.

PMC's setup most likely uses a modified distributor for crank signal to ECU then some sort of coil on plug setup and an ignitor depending on what ECU you are going for. Maybe you should just fit the factory efi first so you can see how it all works if you are going to do it yourself.

 

 

No offence but it seems you have a pretty limited knowledge when it comes to engines so you are going to be pushing it to get an off the shelf ITB kit to work. When you start going custom, everything is eleventy times harder. If you can't afford an off the shelf kit, just get a set of 40mm triple carbs. Way more simple to set up and around the same power for what you are talking about.

[dat2kman]

I have a set of the larger Silvertop 20 Valve 4AGE intake setup complete, for sale, if you go that way!

[Zedman240®]

Best way to get everything you need is just buy the parts you need as they come up second hand. The cost spread over 12 months lessens the financial "blow" compared to buying it all in one hit. It took me several months to put my setup together. Fuel pumps, injectors and 280ZX Turbo dizzy are some parts you can get cheaply second hand that will work well. ECU's come up from time to time on ebay around the $500 mark. Manifolds come and go regularly. Hardest part to come by I think are the throttle bodies. Buy 1 a month at approx $400 each then you'll have the most expensive items to start with. If you are not in a rush, the better it is for you to do research as you go..

[DreamZproject]

See, to me carbs seem wayyy more complex... i love the idea of set and forget, i don't want to have to be out

there every second weekend turning the damn things. I get that carbs are cheap and still excellent performance

but especially considering i want to run AC i just think its too much onging hassle. While i do have limited

knowledge at the moment, i am quite adapt at picking things up. When i was 18 i built a full HD projector from

scratch. Sure it wasn't perfect, but I also have my dad who knows a decent amount about cars who can help

somewhat.

I would still be relying on support of other people, but that i am willing to pay for.

Yes perhaps a custom manifold/plenum chamber and large throttle body may be the way to go... I'll do a little

research in to these.

 

Dimitri, that's the sort of thing I'm thinking of doing. Does the 280zx distributor do the job? I'm not looking for the

most crazy precise setup. Which throttle bodies did you end up using? because I've seen a few of the toyota ones

reliably lowly priced on ebay...

[KatoKid]

Buy these, 50mm ...bit over $300 probably by the time they are landed. If they dont work out little skin lost from nose and resell anyway.

 

S54 stuff out of the US is very cheap now. Plenty of work to be done to mate to a two valve non crossflow head vs 4 valve crossflow but what the hey....good test of your willingness to learn

 

http://www.ebay.com/itm/01-02-03-04-05-06-E46-BMW-M3-Individual-Throttle-Bodies-Body-ITBs-/271325736868

[Jason89]

Cheapest dizzy option would be fitting a rb30 optical cas to the 280zx distributor housing, works perfect.

 

[nizm0zed]

You wont be tuning carbies every second weekend, unless your the type that likes to fiddle with them and you mess the tune up...

 

Get the carbs tuned by a pro that knows what they are doing and it'll be a once a year thing to keep them in optimal tune, you could even leave it a couple of years if you were real lazy and it wouldn't affect much.

 

So, back to EFI.

If you want ITB, you are going to have difficulty in getting a clean vac signal for a MAP sensor. (its not impossible)

This means you'll probably need to use an ECU that has Throttle Position Sensor mapping, or uses a Mass Air Flow sensor. (or both ect)

A MAF sensor setup will then require an airbox plenum, pipework and the MAF between the plenum and air filter.

That will probably take away from the ITB trumpet look you are going for?

TPS load sensing ECU's arent as precise as MAP load sensing ECU's as the computer is measuring the engine load from the throttle percentage opening, rather that from the TPS and the MAP sensor. The map sensor gives the ECU a negative and positive, if applicable, pressure reading from the manifold, allowing the ECU to calculate the accurate load of the engine, rather than only what your right foot is feeding it via the throttle.

 

On to ignition triggering.

The 280ZX system has two types of trigger.

There is the inductive type, looks like a 6 sided star on the dizzy shaft that goes past a sensor. Its a basic yet reliable trigger, It'll send a pulse to the ECU for each cylinder, with no home no.1 signal. Its an electronic version of the old points style dizzy.

If the ECU doesnt know where no.1 cylinder is in the cycle it cant fire individual coils or injectors. It fires them all for each pulse.

For injectors this is fine, bit heavier on fuel but still works.

For the spark, it means you run a single coil and dizzy cap to 'select' the right cylinder.

The other type of trigger is an optical trigger.

In the standard 280zx its basically the same as the aforementioned inductive type, it has a chopper disc inside that has a lot of slots on the outside to indicate the degrees the crank is at, and six slots on the inner ring, giving a pulse as each cylinder comes up.

Its worth noting that the RB30 dizzy is exactly the same setup, 6 uniform slots around the inner ring, with the spark distributed through the cap.

 

There is also the 280ZX turbo style optical dizzy, its physically bigger but works the same as above, with 6 uniform slots around the inner ring.

The bonus with that one is the Z31 chopper disc will fit in it, this disc has one of the inner slots bigger than the others, giving 1 big pulse and 5 uniform smaller pulses.

The ECU can use the bigger pulse as a home no.1 signal, allowing control over individual coils and more refined multipoint injection.

If you do go for the bigger 280ZX turbo optical dizzy, you need the splined shaft that drives it, keep that in mind when your looking for one.

 

 

My advice?

Sure, have a crack at it, you'll learn a lot going in head first, but it wont be cheap and you'll probably pull out most of your hair, trust me on this, been there, done that.

If you can find someone selling a complete running setup, buy that, you'll save yourself so much pain.

Ideally, you would be best just coughing up the several thousand $$$ and paying a performance workshop to do all of it for you, but where is the fun and learning in that?

 

If you have any questions hit me up, im happy help out and share my knowledge.

[bluerat]

G'day Mate, we have just gone through/done all of this and the first thing I would do is find someone local you can trust to help you set it up and tune it, chat to the local Dyno guy as well and see what they use and recommend, maybe, if you haven't already, join the local CAMS car club and see what everyone there uses. I went with Motec, simply because there are 10 local guys who use them, have all the cables, programs etc. The guy who did it for me has it on his own 200B rally car, has set up heaps, along with the auto sparky I used. We had a good relationship with EFI Hardware, brought gear off them and took their advice, same with Motec with the Lamder, sensors, etc so it was really just plug in and play. I started off trying to do it on the cheap, and in the long run it cost me more than getting the right advice straight up, and it works perfectly.

 

We used a 'Scando' modded RB30 Dist and VL (turbo) fuel pump and 6 x LS-1 Coils. We run everything through the computer which logs oil pressure, water temp and all the other hoo-harr and the only tuning so far is on the road using the Lamdar. Also using the Motec wiring harness etc was a smart move.

 

Hodgo

[Zedman240®]

I'm using the L28ET distributor; they can be found if you are looking hard enough. I know where there are several units if you need one now. As for the throttle bodies, I'm using the EFI Hardware ones. Mine are the older version without the air bleed screws. They work perfectly for me anyway and if you look on the net constantly, you will find some for sale second hand. Injection Perfection also manufacture Weber styled ITB's; you can always shop around and find the best price.

[KatoKid]

http://www.extrudabody.com/servlet/the-257/Kit-cln--Datsun-L6-for/Detail

 

These...don't know if they are any good but reasonably priced. Still need ECU, ignition, fuel system plus dyno time  = $$$$$$

[Zedman240®]

http://www.extrudabody.com/servlet/the-257/Kit-cln--Datsun-L6-for/Detail

 

These...don't know if they are any good but reasonably priced. Still need ECU, ignition, fuel system plus dyno time  = $$$$$$

 

ECU=~$500

Surge tank / lift and EFI Pump and lines = $250

Ignition = L28ET dizzy, Ignitor, coilpack leads etc $400

Some new but most parts are second hand and dyno time is needed no matter what you have setup be it carbs or the EFI but the difference with the EFI is it's all done with a laptop and don't need to pull carbs apart every run to change jetting..

[53-681]

Buy an RB25. It may end up costing $500+ than setting up ITB's, but you will have a newer engine with perks over the 'L'egacy series engine that's currently sitting in your engine bay.

 

Scoota G should be able to work something out for you if you're serious.