Projectcar: dual injector setup

[The Doc]

Hi,

I am looking for some technically sound and contributive input from the community, for the next challenge with my Project.
To provide you with the necessary setup background:
In this project I will be using a standalone ECU (prob. DTA S80 Pro), the upgraded CT12/tdo5-16g twins by MDCMotorsports, running approx. 20 (to 26) psi, the ebay intake mani, 2,5 - 2,75" IC piping, dual Walbro's. Powergoal approx. 370kW@rear wheels.
Probable track goal: endurance racing, so reliability is of the utmost importance.

I've been advised by the (race-)tuners that I should consider a dual injector setup for my Projectsuup, instead of just putting in some bigger injectors.
After hearing the pro and con's, I am very tempted to go that route.
The primairy injectors would be sufficient during idle and cruising, and the secundairy ones would come in play when the need for fuel increases.
It follows more or less the principle of the new Lexus GS450h, with the D-4S injectionsystem (http://www.greencarcongress.com/2006/09/more_details_on.html or I could point at the 2006 Suzuki GSX-R750, which is even more advanced).

The considerations are as followes:
1. Better fuel economy (and emmision values) while cruising
2. Better manageability, especially during idle/cruise, when the bigger injectors would have a very short injectionfase, which is why they would be more susceptible to small deviations in currents = unequal fuel distribution.
3. Same reliability.
4. The greater usability of the car, for the track but also to go on holiday to Italy with it. :icon_bigg
5. Price, which would be about the same.

Con's: non till now.

 

[Ric]

I'm sure you got told alot of good information, but I guess they didn't know shit about the 1JZGTE.


If all you want is 500whp (370kw), thats childs play.

First off, don't bother with that upgraded CT turbo thing. Get a nice 67mm turbo.

Second, stock ECU is fine. Just get a MKIV fuel pump and 550cc injectors. To tune, get a SAFC2.

On 18psi, you'll be looking at around 500whp on 93 octane fuel.

Fuel miledge? 23 city, 30+ highway.

Just in case your wondering, I just described my cars setup to you. It works beautiful, I drive it everyday and it gets better fuel mpg then my ex-wifes honda prelude.

 

[IJ.]

Staged Injectors..... welcome to 1990

 

[Ric]

Staged Injectors..... welcome to 1990

LOL... and for better spool he should dual charge it with a supercharger pushing the turbo

 

[foreverpsycotic]

ide reccomend something better than an afc, emanage or map-ecu(1 or 2) comes to mind. oh, and ide also go with more than 550s, for peace of mind.

 

[Rich]

For the powergoal you want, even a 63mm would suffice. And if you want reliabillity you want the least parts as possible > less chance of anything failling, also the more electronics, the more troubles getting it right.
And up to 720cc injectors you don't need to worry about idling or mileage, I have 800cc's and with a blitz ecu and emanage blue it idles like stock (took some time to get it right, but I managed it) and with daily driving consumes about 1:9 (ltr to km's).
Like Ric says, keep it simple and get a good single with supporting mods and you're good to go.

 

[foreverpsycotic]

he already ordered and recieved the twins IIRC. besides, they look stock:evil2:

 

[The Doc]

Staged Injectors..... welcome to 1990

What is/was the downside of these?

 

[Freshmaker]

For the sheer amount of fuel, you don't need a dual setup. Just get bigger injectors like everyone else.

However, better atomization can be had if the second stage injectors are places further from the intake valve. This gives the fuel more time when higher in the RPMs. As well as the benefits of smaller injectors for lower HP needs as you mentioned.

There are a ton of people that will tell you that its not needed because everyone else uses single stage. Just because something works doesn't mean it can't be improved upon though.

Cons would include the complexity of the system and tuning if this is your first time with this type of setup. But, If you have the backing of experienced race-tuners it wouldn't be a big deal.

 

[The Doc]

For the sheer amount of fuel, you don't need a dual setup. Just get bigger injectors like everyone else.

However, better atomization can be had if the second stage injectors are places further from the intake valve. This gives the fuel more time when higher in the RPMs. As well as the benefits of smaller injectors for lower HP needs as you mentioned.

There are a ton of people that will tell you that its not needed because everyone else uses single stage. Just because something works doesn't mean it can't be improved upon though.

Cons would include the complexity of the system and tuning if this is your first time with this type of setup. But, If you have the backing of experienced race-tuners it wouldn't be a big deal.

Thanks for the technical insight and you have read my situation correctly.

I will not be doing the actual tuning myself, but it will be done by some very experienced race-tuners, who have worked with this kind of setup in different types of racingcars (but mainly rallycars).
The thought of the alternative route is very appealing to me (look at my twins). :naughty:
By the way the frontiers of the setup (prob. +500kW) shall not be explored, as there is no point in doing only halve a race but with a +500kW car.

So because for the tuners the given technical complexity isn't a problem, I would like to know if there are some serious considerations against this type of setup before giving this a go.

Wasn't there a 600hp Supra with dual injector setup a while ago? It had some problems if I recall correctly. Does anyone know who the builder was?

 

[IJ.]

Doc: It's an added layer of complexity that really isn't needed (2 x the chance of an injector going bad then you have 50% of the fuel needed and make yourself a lovely oxy torch that WILL burn through a piston if it happens during a hard pull)


If you buy a quality set of injectors there's no reason it can't be tuned for good economy and still have enough overhead for power.

A modern BB turbo like a 3540r will get your goals and be so much more responsive doing it.

 

[Ric]

I get over 30mpg on the highway with 550cc injectors.. cruising at 80mph.

My setup exceeds your goals, so the proof is in the pudding. Tell that tuner to retire the bell bottoms

 

[The Doc]

Doc: It's an added layer of complexity that really isn't needed (2 x the chance of an injector going bad then you have 50% of the fuel needed and make yourself a lovely oxy torch that WILL burn through a piston if it happens during a hard pull)

Thanks, That is a real good argument AGAINST this setup!
So I ordered a 6 pack of 680cc <1% flowmachted Delphi's @ Fiveomotorsport :icon_bigg

If you buy a quality set of injectors there's no reason it can't be tuned for good economy and still have enough overhead for power.

30 mpg as Ric stated is very hard to believe, unless you use the UK mpg definition.
Neither with my standard japanese JZA70 nor my '87 N/A!, I get that kind of mileage, but I think I should be able to equal or better my current 1JZ mileage (21mpg) with a good tuning of my standalone (DTA S80Pro) and these 680 injectors.

A modern BB turbo like a 3540r will get your goals and be so much more responsive doing it.

Yes, maybe for my next project, but for now I'll stick to my special twins :evil2:

 

[buckshotglass]

I think you are the only other person I know of on this site planning to use the DTA like me. I think it's going to be great.
I'm just using 6 injectors.
Dave

 

[annoyingrob]

30 mpg as Ric stated is very hard to believe, unless you use the UK mpg definition.
Neither with my standard japanese JZA70 nor my '87 N/A!, I get that kind of mileage, but I think I should be able to equal or better my current 1JZ mileage (21mpg) with a good tuning of my standalone (DTA S80Pro) and these 680 injectors.

My 1JZ GT40-88 got 24mpg on the highway cruising at speeds ranging from 140-200+km/h.

 

[The Doc]

My 1JZ GT40-88 got 24mpg on the highway cruising at speeds ranging from 140-200+km/h.

That is a nice mileage, about what I was aiming at, during cruising and/or holidays :sonic:

(My N/A does around 28mpg on pumpgas (95 RON = 91 PON) on long rides, but A/F is a bit rice)

 

[The Doc]

I think you are the only other person I know of on this site planning to use the DTA like me. I think it's going to be great.
I'm just using 6 injectors.
Dave

Well, they have proven themselfs over and over again for many years, f.i. at the (Paris-)Dakar rally.
Since I want a "bullet-proof" TT setup for endurance racing, I looked at the Dakar rally, as that is as endurance as it comes IMHO :biglaugh:
Which type of DTA do you use?

 

[Boostage]

I get over 30mpg on the highway with 550cc injectors.. cruising at 80mph.

:bsflag: :bsflag: :bsflag:

 

[buckshotglass]

Well, they have proven themselfs over and over again for many years, f.i. at the (Paris-)Dakar rally.
Since I want a "bullet-proof" TT setup for endurance racing, I looked at the Dakar rally, as that is as endurance as it comes IMHO :biglaugh:
Which type do you use?

That's cool. I live near the guy that I hear is the best tuner for the DTA in the US.
I have a DTA Fast pro 8, but my car isn't running yet.

 

[The Doc]

It seems we have almost the same type then, cool! And very convenient having a expert close by.
My projectcar is at the tunersshop as we speak, with the engine in the proces of being balanced and blue printed.
They have one the best european DTA tuners for rally-cars working there.
It's a wicked standalone, with lots of room for additional features to be added and configured in the future, like alcohol injection and cooling, etc.
If everything goes by plan (which does not completely => http://www.supramania.com/forums/showthread.php?t=55394 ), my engine should be up and running around new year. I am having a bit of delay with the new pistons and clutch, because of the upper, but that will be no more than 2-3 weeks :evil2: