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Secondary injectors. What and where? LOL

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Hi all,

What exactly are secondary injectors and where are they. Are they the same as the 8 primary injectors?

As you can tell, I have no idea about it.

John

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Hi John,

The secondary injectors are located at the front of each plenum bank.

They are a different design to the primary injectors and are only called into duty at high engine loads - they provide the necessary fuel to suppliment to flow available from the primary injectors.

Due to the fact that are only operational when you are in with a wide throttle opening and revs, the have no impact on idle or moderate throttle operation.

Cheers,

Mike S


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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Hi John,

The secondary injectors are located at the front of each plenum bank.

They are a different design to the primary injectors and are only called into duty at high engine loads - they provide the necessary fuel to suppliment to flow available from the primary injectors.

Due to the fact that are only operational when you are in with a wide throttle opening and revs, the have no impact on idle or moderate throttle operation.

Cheers,

Mike S

Thanks Mike, I've been wondering for a while now. Wha about on startup?

John

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Hi John,

The secondary injectors are not used in start-up, they are only used when the engine is under high load.

The only problem that I have heard of on the V8 secondaries are those ossociated with poorly sealed installations and leaking.

CHeers,

Mike S


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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Mike---why do you think Lotus put a secondary injectors instead of configuring the 8 injectors a bit bigger?

Do you think its a cheap way to pass the federal emission (leaner).

Hi John,

The secondary injectors are located at the front of each plenum bank.

They are a different design to the primary injectors and are only called into duty at high engine loads - they provide the necessary fuel to suppliment to flow available from the primary injectors.

Due to the fact that are only operational when you are in with a wide throttle opening and revs, the have no impact on idle or moderate throttle operation.

Cheers,

Mike S

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I recall reading the explanation in the workshop manual about the secondary injectors, with some amusement. I forget the exact wording but says something alone the lines of, 'high loads and high air flow at road speeds in excess of 135MPH..'!

Now 135MPH I recall as maximum revs in 4th. So I recall thinking that thos may be one way the torque is held back by the ECU in the lower gears.

I know you can't do it, but always thought it would be fun to be able to interogate the ECU to see for how long in a cars life those injectors have been used..

Jeff

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I imagine that the design included the use of these


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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...Now the car is being sold, I guess I
Edited by G

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to name the things if I see them, that's what I call integrity..

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Hi G


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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Mike it's bad to hear that you want to sell the road car , hope we can see the car in real at the JCR'08. Can understand the point with the race car. With all that stuff associated in the package it is really only for a private race-team. Or maybe a collectors item. But the road replica is a good version for normal use. I would hold it in my hand if I'm in your position.


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to name the things if I see them, that's what I call integrity..

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The reason for the secondary injectors is that if the engine used large primaries only, it becomes difficult for the ECU to control fueling at low rpms and low loads. Fuel injectors are most efficient and best controlled at high duty cycles. If you put huge injectors in there and drove around at normal traffic speeds, the engine would be very unresponsive.

So Lotus uses secondary injectors to deliver more fuel at high load and high rpm only, and maintain street drive ability with smaller primaries that are sized correctly for average driving.

Same reason the 4cylinder Esprit SE-S4s and GT3 use two secondary injectors.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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The reason for the secondary injectors is that if the engine used large primaries only, it becomes difficult for the ECU to control fueling at low rpms and low loads. Fuel injectors are most efficient and best controlled at high duty cycles. If you put huge injectors in there and drove around at normal traffic speeds, the engine would be very unresponsive.

So Lotus uses secondary injectors to deliver more fuel at high load and high rpm only, and maintain street drive ability with smaller primaries that are sized correctly for average driving.

Same reason the 4cylinder Esprit SE-S4s and GT3 use two secondary injectors.

Although I can follow the logic of that theory/explaination, I don

Edited by mike_sekinger

1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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I wonder if it's to do with using the fuel from the secondary injectors to cool the charge? The Lotus Carlton has a charge cooler so doesn't need secondary injectors????

I'm sure there was a post a couple of years back from a guy who worked on the design of the V8. I'll have a search later to find the post.

Regards,

Peter.

Although I can follow the logic of that theory/explaination, I don

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That may be another factor..... although the idea of designing and Engine Management that kills power to combat high inlet temperatures defeats me.... :respect:


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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Hi All,

I have to chime in there.

Some years ago I also was thinking that the secondaries (on the V8 Esprit) are just there for cooling the intake charge, because of the No-Intercooler-Design.

Thats why I did a test and removed the electrical connectors from the secondaries and put in a load/resistor to fool the ECM to prevent the CEL coming on.

The result was a quite lean condition at boost 0.7-0.8 bar (with the red ECU installed) around 12 A/F what is too lean for high reliability and also max. power.

My intension why I did this test was to use the secondary ports for water/alcohol injection just for cooling reasons. But now I know that they are not only there for cooling ....

Cheers

Marcus

That may be another factor..... although the idea of designing and Engine Management that kills power to combat high inlet temperatures defeats me.... :o

Marcus

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Absolutely right - if you disconnect the secondaries for whatever reason, you should not place the engine under heavy load/boost. It will be too lean.

The query was, if the secondary injectors are called into play in the fuel dumping at high inlet temperatures, or if the pulses on the primaries are extended. I simply don

Edited by mike_sekinger

1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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Hi Mike,

The secondaries come into play triggered via rpm, boost and load. Its not definitely linked to the main-injector-pulses.

But, what I have experienced is that the pulses always were higher than 75% when the secondaries came into play.

This is a sign that the primaries are maxed-out in these conditions.

Of course you now could think about bigger primaries ... but if you do that you will most likely get idle and tickover problems ...

This is the price you have to pay for economy and low-noxious exhaust gasses on these wide-power-turbo-engines ....

With a N/A V8 engine you wont have these problems, because the power band is not that wide.

Cheers

Marcus

Absolutely right - if you disconnect the secondaries for whatever reason, you should not place the engine under heavy load/boost. It will be too lean.

The query was, if the secondary injectors are called into play in the fuel dumping at high inlet temperatures, or if the pulses on the primaries are extended. I simply don


Marcus

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V6? i thought they have used the old Opel straight six....


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to name the things if I see them, that's what I call integrity..

*********************************************************************

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What is the compression ratio and max boost of the Carlton/Omega?

3.6 litre straight six

8.2:1 compression ratio

Max boost 0.7-0.75 bar boost

I


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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That may be another factor..... although the idea of designing and Engine Management that kills power to combat high inlet temperatures defeats me.... :o

Does race engine modified for road use explain it?

Jeff H

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Does race engine modified for road use explain it?

Jeff H

Well, I


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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