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MrDangerUS

Bosch K-Jetronic CIS tuning, 86HC, 87HC, 88 X180 Esprit

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Bosch K-Jetronic CIS tuning, 86HC, 87HC, 88 X180 Esprit

Majority of the Lotus owners are of the opinion, that Bosch K-Jet CIS equipped Esprits would not respond well to common performance improvement practices. In my opinion, there are several approaches, which offer quite significant improvements in fuel delivery.

Since early 1980-s, some Peugeot, Porsche, BMW, Saab, Volvo, Audi, VW and Mercedes racers have been successfully tuning their Bosch injected cars, (just Google “K-Jetronic CIS”). I don't see any reason why 86, 87 and 88 Lotus Esprit should be different. From engineering point of view it is not the easiest task, but, it is quite feasible.

Bosch K-Jetronic CIS system is a very reliable, purely mechanical system consisting of two-in-one hydraulic pressure circuits. Control Pressure System assumes the role of modern ECU and controls the so-called System Pressure Circuit. SPC supplies volume of fuel under a specified pressure to non-sequential (continous) mechanical injectors. Both circuits interact with each other by the means of fluid pressure and the Control Plunger. Principles and components explained in

http://www.diagnostic-assistance.co.uk/mech_inj.htm

In the Fuel Distributor, which contains and controlls both pressure circuits, the amount of Control Pressure determines how far the Control Plunger travels in the bore of the fuel distributor regulating the fuel pressure drop across the metering slits of the System Pressure Circuit. The Control Pressure is a hydraulic counterforce pushing on the bottom of the Control Plunger.

On Bosch K-Jet equipped cars there are two ways to increase fuel delivery. One can achieve it by lowering the Control Pressure (WUR setting alteration), or installing a Raising Rate Adjustable Pressure Regulator in the System Pressure circuit (injector supply side).

It seems counterintuitive, but HIGHER control pressure(CP) causes a LEANER mixture.

You want low CP with a cold engine for enriched mixture at idle, and higher CP for leaner running with a hot engine. One can lower the CP at any time by introducing simple alterations to the WUR set up.

See http://forums.vwvortex.com/showthread.php?1899508

or http://www.pelicanparts.com/te...g.htm

I believe the WUR on Esprit CIS could be modified in similar manner.

Here's an article on "knocking the plug", Adjusting your warm up regulator.

Don't do that unless you're running a bigger turbo, modified engine. More air flow or denser air comes first.

Make sure you have access to fuel, FAR ratio and exhaust meters. ($66 pressure tester: http://garage.ideola.com/prod-Tools.html, http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320675136273&ssPageName=STRK:MEWAX:IT)

ADDITIONAL READING on CIS TUNING:

http://www.saabcentral.com/forums/archive/index.php/t-63216.html

these may also interest you:

Part 1:

http://www.motorsport-developments.c...AF268_tech.pdf

Part 2:

http://www.motorsport-developments.c...AF269_tech.pdf

Part 3:

http://www.motorsport-developments.c...AF270_tech.pdf

OTHER ARTICLES

http://www.motorsport-developments.co.uk/stus.html

http://forums.vwvortex.com/forumdisplay.php?986-CIS-Injection

BOOKS EXPLAINING CIS SYSTEMS :

How to Tune and Modify Bosch Fuel Injection (Motorbooks Workshop), B Watson

ISBN-10: 0879385707

Many good points and lots of information and specifications for all Bosch systems. From the earliest VW systems to the latest. The modify section is short and lacks greatly.

Bosch Fuel Injection Systems, Forbes Aird

ISBN-10: 1557883653

This easy to read manual includes basic operating principles of Bosch's CIS K-Jet, KE and pulsed fuel injection systems; D-L- and LH-Jetronic, and LH-Motonic tuning and troubleshooting; and some info about high-performance applications.

The Best Book:

Bosch Fuel Injection and Engine Management: How to Understand, Service and Modify, Charles O. Probst

ISBN-10: 9780837603001

Thhis is an authoritative manual on Bosch Fuel injection. This is the only book that fully explains all aspects of these Bosch systems: Motronic, L-Jetronic, LH-Jetronic, LH-Motronic, D-Jetronic, K-Jetronic, KE-Jetronic, and KE-Motronic. You will find specific information on the newest KE-Motronic and LH-Motronic systems that is not available from any other source.

So, What Say You?

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Electronic warm up regulators are available that allow the electronic control of the control pressure. I have never used one but they have been used on the Porsche 924 Turbo.

CIS is generally considered to have a limit of around the 250-300 bhp mark, this has been bypassed in some cases by fitting a fuel distributor from something like a Porsche 928 (V8) and using 2 injectors per cylinder.

Biggest problem is that the fuel delivery is effectively only tunable at one point. The 'fuel map' is set by the physical shape of the fuel distributor flap valve housing.

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Greetings Rich,

Thank you for the response on this unpopular topic.

Any pointers are appreciated.

Considering that 86-88 K-Jet Turbos have approx 210HP, for me, increase to 300 is more than enough.

(My next worry will be the tranny.)

The flap in the distributor has some fudge factor built into it. It will respond to mild air mass demand increases.

The bottle neck on 86-88 is sh...y turbo and restrictive ducting & plenum diffuser.

Do you have any specific info on 924s? Was that electronic control of the control pressure available on 944T?

Cheers

John

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Interesting article from Porsche Club of America how to do it yourself:

Guest Technical Article:

Warm-Up Regulator Ajustability

Bob Tindel

[email protected]

The article on making the WUR adjustable is by Jay Pineau, Ark-La-Tex Region, PCA, in Volume VII, pages 116-117 of Up-Fixin. In case you don’t have that, here is the text:

"An engine equipped witha Bosch CIS (K-Jetronic) fuel injection system depends on the accuracy of the control pressure for starting and drivability performance. If during a system pressure and performance test it is determined that the warm-up regulator is at fault, you are faced with an alternative: replace it (list price now about $280) or attempt to repair it.

The regulator is a fairly simple device which varies the control pressure with temperature (both engine and self-induced via an internal heating element). There are two main causes of malfunction: heating element failure and foreign material in the metering chamber.

A quick check with an ohm meter will determine if the heating element is defective. It should read 18 to 22 ohms resistance (I didn’t get this exact reading, but it wasn’t an open circuit). If the element is faulty, the regulator must be replaced unless you can locate a replacement heating element from a used regulator.

If satisfactory, the regulator can be carefully disassembled and cleaned. Take care that the two small orifices are completely clear. If the diaphragm shows any wear, flip it over at reassembly. (Be careful here—the diaphragm is VERY thin metal. I didn’t disassemble the bimetal spring, just pushed it aside to remove the diaphragm.)

After reinstallation, it may (WILL) require readjustment to obtain correct pressure relationships. (These pressures vary with the year of the car and the part number of the WUR. You can find them in the shop manual. If you don’t have them, I can xerox and snail-mail)

Bruce Anderson described in PANORAMA (October 1984) how this adjustment can be accomplished by "knocking the plug". The only problem with this procedure is if you "knock" it in too far, you must remove and reassemble the regulator to "knock" it back (indeed true, I tried this method). By the time you have obtained the best cold and hot values, you may have to do it several times.

The unit can be modified to provide for external adjustments by the addition of a pull-out screw and nut which permits very accurate movement of the plug."

The article also includes a diagram, but essentially you drill and tap a 5mm hole about 10mm deep into the center of the plug. Then drill a second 1.5mm hole in the crack between the plug and the WUR body. Put a 1.5mm roll pin in this hole and tap it down flush with the body (the idea is to keep the plug from rotating when you move it up and down with the pull-out screw).

Put a 5mm allen-head screw, with a washer slightly larger than the plug, and a 8mm diameter nut, into the 5mm hole. Keep the nut backed off, and gently tighten the screw until it bottoms in the hole. Now, to raise the plug (higher control pressure), hold the screw with an allen key and tighten the nut (it’s a tight fit, but an 8mm box-end wrench should fit over the head of the screw). To lower the plug (lower control pressure), hold the screw, back the nut off, and then tap the screw (I use a brass drift and it takes a fairly hard whack).

Of course, while you are doing any adjustments, you need to be looking at the control pressure. I bought a CIS gauge from J.C. Whitney for less than $60. Be sure that the electrical connector to the WUR is disconnected when setting cold control pressure, and that the engine is dead cold. To get the fuel pump to run, jump terminals 30 and 87a on the fuel pump relay socket (on my 83, it is the red relay in the luggage compartment).

If your car doesn’t have an O2 sensor, you are completely dependent on correct fuel pressures and mixture setting to get the engine to run correctly, so the WUR is important. After I did the WUR modification, I am confident that I can set my engine up properly, and it starts and runs perfectly, cold or hot.

Bob Tindel

[email protected]

Edited by MrDangerUS

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Yes I've seen that before, a control pressure gauge would be a good idea if you are modding this stuff which can be bought in a few places. The 944 Turbo has full EFI; only the 924 Turbo, 924 (N/A), 928 and some of the 911s had CIS.

I'll try and find the details of the WUR controller later on - it'll be on the Oz 924 forums (924board.org) somewhere (its a worldwide board - most members are in the US!)

Rich

Edited by Rich H

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Rich,

Thanx

My WUR # 0438140026 cross refferences to 86 Audi Quattro 5000 w/2.2 L ,16 v, 4 pot engine and various Volkswagens, Rabbit, Sirocco, Dasher,Jetta, etc. The same number.

Adjustable (pre-setable, rather) unit is sold for $330 by Brian Leask here http://members.cox.net/930wur/

Also, I found a discussion about electronically controlled WURs

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/379783-digital-wur.html

It looks like TurboKraft has developed a digital WUR. I did send them an email with some questions.

Also, UnwiredTools has one, http://unwiredtools.com/utcis-pt.asp

Wow, I am wondering why no one ever discussed this mod here? DWUR installation opens up a fantastic opportunity for performance enhancements for Bosch CIS car owners!

Edited by MrDangerUS

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Guess I don't need to go looking! :lol:

CIS was fitted to loads of cars over here, Mercs, BMW, Fords, Porsche, Volvos and Audi's the tuning is a bit old hat but there is plenty of it about!

Watch out though the Bosch K Jetronic was found in various modification states, some with lambda sensors some without and other changes too

Then you have the other versions of the Jetronic systems with more and more electronics involved as the system matures.

Good luck!

Rich

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Hi Rich,

Thank you.

Could you expand on "Then you have the other versions of the Jetronic systems

with more and more electronics involved as the system matures", please?

Did 86-88 use the same CPU across the three model years?

What car did Lotus "borrow" the CPU from?

UnwiredTools seems to have a user friendly, complete, (not "under development") D-WUR for CIS K-Jet injected cars, http://unwiredtools.com/utcis-pt.asp

I have sent an inquiry about compatibility of their system w/Lotus engine.

I will post the results of this conversation

Cheers

John

Edited by MrDangerUS

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UnwiredTools seems to have a user friendly, complete, (not "under development") D-WUR for CIS K-Jet injected cars, http://unwiredtools.com/utcis-pt.asp

I have sent an inquiry about compatibility of their system w/Lotus engine.

I will post the results of this conversation

Please do! This has my curiosity aroused for sure.

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Ben, Got an email from the sales person confirming DWUR compatibility with Esprit, but I insisted to talk to a tech-guy.

Their answer:

"Thank you for your note. The short answer is "yes", our unit will work with any KJet CIS system. I am cc'ing Steve who can speak more directly to your specific application."

I hope to talk to this chap after EASTER.

Looks like Porsche, Merc,Audi,etc. guys are doing it for years. Lotus shall not be denied!

Here is the manual for UTICS-PT unit for turbo cars-looks pretty straight forward.

One other thing to watch: Citroen transmission and CWP has to be beefed up. Cryogenic treatment, SKF bearings and LSD is a must!

BR

J

Edited by MrDangerUS

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From what I can see on mine, this system is k-jetronic with lambda so as far as I understand it means two things:

You have a frequency valve located in front of the sensor plate, it controls the lower chamber pressure in the fuel distributor. This in return adjusts your mixture in function of lambda value. Lowering your control pressure will help increasing fuel flow, I agree, but the system will always try to lean it because you'll be running richer at the cat. If your engine mods make the engine thirstier, the closed loop might still work...

Second, this means your ecu is in the way and as far as I know, nothing is reprogrammable in early bosch systems.

Good luck.

Luc

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Even if higher performance is never realised, this unit sounds like a good improvement just simply for solid-state reliability. But then if it DOES improve any aspect of operation... :thumbsup:

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The lambda box is the same era as my 924's ignition control unit, it's all solid state logic circuits, should be easy enough to spoof it....

Even better ditch the frequency valve, lambda and cat altogether...

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The ECU is probably an early 80-s SAAB unit, Bosch PN# 0 280 800 065

I'd like someone to confirm

Is it the same number for 86,87 and 88 MY?

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I found another thread on CIS

Thierry's electronic fuel controller -- discussed at length on the Pelican forum, it does what the DWUR is trying to do.

However, the installation and initial setup is more complicated (http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/482246-electronic-cis-fueling-boost-control.html)

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Here is a "boat load" of information about Bosch CIS K-Jetronic injection tuning, trouble shooting, etc.

http://forums.vwvortex.com/forumdisplay.php?986-CIS-Injection

Megasquirt and other DIY parts:

http://www.diyautotune.com/

Edited by MrDangerUS

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I'd like to confirm that the WUR PN# on our cars is the same. Just to be sure Lotus installed the same parts from 86 to 88.

Mine is Bosch 0 438 140 026

Here are couple other component numbers. DO I HAVE IT RIGHT?

Fuel accumulator Bosch 0 438 170 039

Air by-pass valve Bosch 0 280 142 020 (Lotus# 910E6754F)

Aux. air valve Bosch 0 140 140 143 (82-83 Audi 5000, 81-83 Audi Coupe, VW Quantum)

Fuel distributor Bosch 0 438 100 144

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Here is a posting from Porsche blog about D-WUR

[...]

received the Unwired Tools UTCIS-PT digital warm up regulator and installed it on my highly modified 930. The installation of the product was simple. The user interface for tuning is easy to use. My contact at the company was Steve Schlander, who has been an amazing help throughout this process. He informed me of the upcoming upgrades. The built-in AFR gauge should allow tuning without a dyno! When I got stuck, I called Unwired and Frank tuned my fuel flow over the internet!

With the original warm up regulator my fuel mixture was fat in the mid range and dangerously leans above 6,000 RPMs. For example at 3,700 RPMs my AFR was 10. At 6,150 RPMs, my AFR was 13.9.

We leaned the AFR at 3,700 RPMs to 10.57 and richened the AFR at 6,150 RPMs to 12.81. We then continued the next run up to 6,250 RPMs with an AFR of 12.83. I was completely satisfied with how this digital WUR was able to flatten the AFR curve. With additional fine tuning I am confident that we could have gotten it flatter, but it was late at night and we all needed to get home. I may do some additional tuning in the near future, but I achieved my major objective. I CAN NOW DRIVE MY CAR ON THE TRACK!!!!

My drive home from the dyno was 75 miles during which I noticed an added bonus. My gas mileage on the street doubled!

This product is a great inexpensive alternative to EFI. I am not saying that this replaces EFI but if you need to fine tune your AFR you no longer have so spend several thousand to do it. For my car, there was no money better spent than on Unwired Tools UTCIS-PT.

I have several track events planned for July and will provide an update.

ALSO check following blogs :

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/379783-digital-wur-53.html

http://members.cox.net/930wur/ - this is a mechanical adjustable WUR

The DWUR adjusts control fuel pressure based on both RPM and Manifold Absolute Pressure (MAP). Adjustable via laptop software supplied by Unwired.

Since control pressure can be set at every 250 rpm for each/every MAP from -0.5 bar to +2.0 bar, AFR can be set/managed/maintained where it belongs to optimize engine performance. There should be no over rich or lean conditions from idle, no load - no boost to WOT full load, full boost and everywhere in between.

WOT HP may not change much over a stock WUR but HP and especially torque should improve significantly from 1000 to 5000 rpm.

You will need either a data logger capable of recording RPM, MAP and AFR on the road (aka seat of the pants dyno) to get the DWUR dialed in on an instrumented dyno run by someone who is willing to learn an easy task.

Latest development: the stepper motor has been replaced in favor of a fuel injector serving as a frequency valve

http://forums.rennlist.com/rennforums/911-turbo-930-forum/427188-unwired-tools-utcis-pt-warm-up-regulator-upgrade.html

Edited by MrDangerUS

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The other possible way to control AFR is via frequency valve route.

If Greddys Rebic IV is connected between the fuel distributor control pressure side and the return line to the fuel tank it would control a frequency valve which varies the control pressure at the fuel head. This set up uses map and rpm signals along with frequency valve settings to create a smooth A/F ratio throughout the entire rpm range.

http://www.greddy.com/upload/file/Rebic_IV.pdf

PRETTY NEAT!

Huh?

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/596977-electronic-csi-controller.html

Edited by MrDangerUS

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Brothers in Bosch!

Recently, I have asked Steve a couple questions like:

OK, The frequency valve version looks much more reliable and simple, but

1. DWUR comes from the supplier with a pre-set program/map. How do I know if it is right for my Lotus 2.2 Turbo engine? What are the next steps?

2. What happens if I modify the intake manifold or run more boost in the future? How do I re-tune or fine tune the curve?

What are the steps involved.

3. I'm modifying intake manifold, adding BOV and recovering from "Sudden Death Syndrome" caused by fuel pump failure. Car did not run since Oct 2010. Should I make it start and run first and than change to DWUR, or go cold turkey.

4. Do you have new/revised installation and tuning procedures available?

Answers I have received:

1. As a starting point you can use a map which is setup to factory

Bosch specs. You should try it. There's no charge for the software. You can download it from our website at no charge. I can email you an engine map for your car to play with. I'll bet you'll be editing maps in less than 5 minutes.

2. If you make changes in the future which improve the volumetric efficiency of the engine then you will want to tune it. That's why a dwur is better. The best way to tune non-stock engine parts is to put in a dash gauge for an o2 sensor. That will tell you exactly when you're too rich or lean. If you can see it you'll get a feel for what needs to be tweaked very quickly.

3. There's no Cold Turkey! Our engine management software gives you live data on the fuel system. That makes it much easier to troubleshoot a stubborn engine.

4. The tuning procedures have not changed. The CIS DWUR regulates to a specific control presure based on the conditions of your engine. The engine doesn't know or care of the valve in the UTCIS is a needle valve or a frequency valve.

5. The big advantage of the DWUR over a Greddy/Andial/5th injector solution is that the DWUR isn't just a tuning solution; it's also a real replacement WUR. If your WUR goes bad then one of those tuning-only tools won't do you any good.

Steve

Sent from Steve's mobile mail

Edited by MrDangerUS

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Pump primary 0 580 254 967 (could be substituted by 0 580 254 984)

Pump secondary 0 580 254 979 (could be substituted by 0 580 254 044)

WUR Bosch 0 438 140 026

Fuel accumulator Bosch 0 438 170 039

Air by-pass valve Bosch 0 280 142 020 (Lotus# 910E6754F)

Aux. air valve Bosch 0 140 140 143 (Fits the following applications

AUDI 4000 1982 1983,

AUDI 5000 1982 1983

S: 1982 1983

TURBO: 1982 1983

AUDI COUPE: 1981 1982

GT: 1983 1984

VOLKSWAGEN QUANTUM

CUSTOM: 1983

GL CUSTOM: 1984

GL DELUXE: 1984

Fuel distributor Bosch 0 438 100 144

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FYI: Fabulous Bosch CIS and EFI fuel injection and diesel EXPERT:

50 years of experience. Has many happy US and European customers

(Pumps rebuilding, injectors, calibration, etc,etc)

HANS UTKE

H & R Fuel Injection Ltd.

(631) 589-1600

360 Knickerbocker Ave Ste 12

Bohemia, NY 11716

Edited by MrDangerUS

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D-WUR FOR BOSCH CIS INJECTED CARS

If you EVER considered adding intercooler, larger turbo or more boost - here is the device which makes it POSSIBLE!

I am are in the process of integrating it into Esprit. Work in progress.

Here is a manual describing Digitally operated WUR.

UnwiredTools UTCIS™

Trbo Guys suppose to use UTCIS-PT.

http://unwiredtools.com/utcis-pt.asp

http://unwiredtools.com/manuals/UTCIS_Application_Guide_A2.pdf

If you are interested, PM me for "Group Buy" discount.

Edited by MrDangerUS

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?HOW TO INCREASE BOOST ON 86-88 CARS w/CIS?

"Install electronic boost controller" one may say.

BUT, how to deal with waste gate (diaphragm controlled)?

It would be nice to have a two level "dial up" set up. One for town driving, the other for expressway or track.

Any pointers?

Edited by MrDangerUS

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