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Posted by: howardchen327 Oct 25 2004, 06:30 PM

I did some research on the Kit Carlson EMS. So far it . But I have one question: approx how much performance boost on a "totaly" (except a custom cold air intake) stock 2.0 D-jet I am look'n at?

I know is it kind of meaningless to install the kit on a stock engine, but as the budget concern , the kit is is the only affortable engine upgrade for me right now.

I'm planing to save some$$$ for one of Jake's massive IVs

Any suggestion will be appriciated:)

Posted by: Racer Chris Oct 25 2004, 07:12 PM

If your d-jet is already set up properly you will gain almost nothing by switching to the KC EMS. However, if you also switch the exhaust to a Tangerine Super Header you will pick up gobs of mid-range torque and a bunch of top end as well. Actually you will get all that with the d-jet and my exhaust.
The only advantage of the KC EMS on a stock engine is easy tunability/optimization; something you don't have with the d-jet.
If you have to have the stock type H/Es then there are no power upgrades short of headwork and a cam.

Posted by: Headrage Oct 25 2004, 07:17 PM

Tell me more please!!

Posted by: d914 Oct 25 2004, 07:23 PM

do we have a balpark on $$$$$$ yet and or time frame.

Posted by: 914forme Oct 25 2004, 07:33 PM

depends on what you are looking for?

He is making two kits for us, one rplaces the stock EFI, and keeps a stock type ignition.

The other will also have coil packs - Yeah Dave! Bring it on! This is the one that I am waiting to spend my green on. It will be somewhere in the $1000+ range, so the battle is KitCarlson or SDS in my book. I like the SDS better than the Megasquirt - I have three MS units here and they work well, but the SDS has a very easy to use interface that makes the others pale in comparision. Don't get me wrong I have PC around, but I don't like having to drag one around wiht me to keep my EFI programable. It is bad enough on my OBDII Jettta, let alone in my 914. But hey I do it every now and again. Currently I am running good old D-jet, because it works, and my auto-x class would not favorable with PEFI systems, with my other wise un modified engine. When the D-jet dies, I will box it up, and replace it with something more modern, bump the engine up a bit also, and have some fun.

Take care, Stephen

Posted by: Jake Raby Oct 25 2004, 07:45 PM

We are still testing Dave's systems and having good results.

Posted by: d914 Oct 25 2004, 07:47 PM

will it come turn key, I'm currently running carbs and a little cam. will be going header and would like to go with the Kit c setup for a little more reliability around town. Right now pulling the gas tank and re doing all hoses. Dirty dirty dirty....

Posted by: McMark Oct 25 2004, 07:51 PM

I'll let you know in about a week. Just got the wiring harness modified and installed. Got new spark plug wires. Still need to get a piece from Dave and get the brain talking to the Palm handheld.


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Posted by: Aaron Cox Oct 25 2004, 07:59 PM

that pic makes my head huuuuurt. ever think to zoom out?

Posted by: Jake Raby Oct 25 2004, 08:08 PM

I plan on selling complete replacement systems if someone wants them, or just the Electronics.

I will have 3-4 kits, two of which will be specifically for the 914.

Posted by: Racer Chris Oct 25 2004, 08:31 PM

Allan,
My exhaust is the ONLY bolt on upgrade that will get you nearly a 10% increase in torque and 7% increase in peak power on an otherwise stock 2 liter d-jet engine with stock exhaust. The D-jet actually likes my header due to an improved vacuum signature on the intake side of the engine. Additionally, it will keep up with all the head/cam/displacement upgrades you decide to do down the road. It is the single most effective performance add-on for a stock class autocrosser.
Most 914 owners are too cheap to find this out for themselves. :finger2:
Other headers will give almost as much peak hp increase but not the midrange torque.
BTW, the Bursch is the about worst thing you can add from a performance standpoint.

Posted by: Racer Chris Oct 25 2004, 08:32 PM

WHEN?

Posted by: Jake Raby Oct 25 2004, 09:26 PM

as soon as Dave gets the units back from the production facility we will be getting the kits together..

I just talked to Dave and he verified that he will NOT be offering a system that uses the stock dizzy, all will have the direct fire system with coil packs as well...

Posted by: Hi_Fi_Guy Oct 25 2004, 10:23 PM

Jake,

Thanks for the heads up. I am certainly interested in switching the 2270 over to electronic ignition & fuel injection. Would solve the few remaining issues I have with my 914... smog test & cold starting/running.

Posted by: rdauenhauer Oct 26 2004, 11:33 AM

Not to Hijack the thread but ..Chris how about offering a ver of your header w/HEAT!? Possible?

Posted by: Jake Raby Oct 26 2004, 11:46 AM

he already does!

Posted by: fiid Oct 26 2004, 11:57 AM

Any electronic ignition and injection system ought to be perfect for just about any engine - since you can always jack it into a laptop to tune it.

A fully functioning D-jet/Dizzy is a pretty good setup in terms of performance; going to an aftermarket system won't get you much in the way of extra HP. It will also marginally improve your emissions and fuel economy, and you will gain the ability to diagnose FI problems by jacking a laptop in.

All of the above is also true of the Megasquirt, and other systems around, although a stock megasquirt does not at this time support ignition (although that can be achieved in a couple of different ways.

Posted by: rdauenhauer Oct 26 2004, 12:41 PM

Wow. your right Jake. Sorry Chris I hadnt chked your link in a while.
Though to be honest I did Choke at see the prices.
But as the saying goes: Speed cost money, How fast do you wanna go?

Posted by: Jake Raby Oct 26 2004, 12:43 PM

I disagree..

Yes, any engine may "work ok" with carbs or FI, but it will not be optimized unless specifically built for either application!

A good case is my 912E. I built the engine for carbs only and ran it for 59K miles that way. When we installed the FI the tuning procedure took longer than normal and my idle is not at a premium due to lack of vacuum signal due to a cam ground on a 105 degree center keeping the plenum scavenged drastically. The engine runs okay, but could run and idle better with a combo made for FI.

Sure it will work, but it won't make as much power nor will it tune as easily. So, why do it half assed?

There is nothing that pisses me off more than generic things that are "universal"... One size fits all don't cut it around here.

Posted by: howardchen327 Oct 26 2004, 01:49 PM

Wow a lot of comments & suggestions! Thax guys! u guys r awsome

So there is not much performance gain if I switch to KC EMS...but will the kit be easier to tune up and maintain compare to the stock FI? With KC EMS do I have to mess around with point (this thing makes me sick )...I love my tenner very much, but don't know much about cars

Posted by: Mueller Oct 26 2004, 02:28 PM

howardchen327,

for about $100 or less, you can eliminate your points right now with a Pertronix or other brand point replacment kit.

Posted by: fiid Oct 26 2004, 03:50 PM

EFIs respond to the same set of variables as carbs do, only they (usually) take into account far more variables than carbs do. Carbs respond mechanically to quite a narrow set of variables, and usually do so in a compromised way. So any set of variables that CAN be manipulated with carbs, CAN also be handled with FI. Usually with modern EFI systems, this is a lot easier because you don't have to (using the SU as an example) get different profiled needles to handle different power curves.

The clinching datapoint here is that an FI system CAN read an oxygen sensor and run closed loop (thus calibrating itself).

NOW: CAN and DO are different - poorly set up carbs are crap, and so is poorly set up FI. Correctly set up FI should be able to generate equal power to a well set up carb system, but will likely have a better emissions profile and better efficiency on the same engine.

You are right that cams with a poor vacuum profile can foil MAP (manifold pressure based FI systems. That is easy to fix with a megasquirt - you just run Alpha-N (throttle based) instead of map based. With other systems you may be able to go to MAF (mass air flow - which is basically how carbs work).

There are other ways to fuck-up both systems (lack of sufficient fuel delivery, etc etc), but at the end of the day you have much better odds of getting the ideal mixture out of FI than carbs since FI uses more input variables than carbs do, and can sometimes even tune themselves based on huge numbers of variables. You would need a carb the size of Babbages differencing engine to be able to do that with mechanical setup.

Posted by: fiid Oct 26 2004, 03:55 PM

BTW just to be clear on my concession on one point - MAP (pressure) based FI is a hack. It is based on the ideal gas law:

pv = nRT

Which basically (applied) says you can calculate the volume of air going into the engine based on the pressure and tempurature (MAP and MAT) of what is in the manifold.

MAF based systems are actually a little better in that they measure the weight of air travelling past a "flapper" (L-jet does this) rather than doing the math, which can get tripped up by other variables.

Having said that MAP is easier to implement, and bypasses som reliability problems with MAF sensors.

Posted by: lapuwali Oct 26 2004, 04:26 PM

Which is also the way K-Jet works, just using an all mechanical system instead of an electronic system.

Not all MAF systems use the flapper. Nearly all (if not 100% of them) that use MAF (which is damn near 100% of current OEM systems), use the "hot-wire" MAF meter (MAF = mass air flow). MAP, throttle position, RPM, and air temp are all used in the attempt to guess how much air is flowing into the engine (thus, how much oxygen, which is really what you want to know). Measuring the airflow directly is far and away the most accurate method, which is why it's universally used in OEM systems today.

The hot-wire meter, rather than using a flapper, uses a thin wire or thin film that's designed to get hot. There's a temp sensor at one end and a current sensor at the other, and the system attempts to keep the temp of the wire/film constant. As the airflow mass increases (or the ambient air temp falls), more current is required to keep that temp the same. Thus, the current applied to the wire is directly proportional to the amount of air flowing through the meter. Relatively little airflow restriction, but there is still some susceptibility to airflow reversion confusing the meter if particularly wild cams are used.

I've not yet figured out why so many aftermarket systems tend to be MAP-based rather than MAF-based. Adaptability is my best guess. New MAF meters are expensive and relatively hard to come by. Used bits off recent cars, however, are becoming more plentiful. Depending entirely on MAF means it's harder to be able to smooth or ignore MAP under those conditions where MAP is unreliable (low-loads with wild cams), and one can use a TPS-based measurement "blended" with MAP at higher loads.

Posted by: Jake Raby Oct 26 2004, 04:44 PM

So fiid,

I suppose that Dave just wasted the last 8 years of his life building a MAP based unit...

May as well stop testing right now, pull the system off my car and burn the bitch.

Posted by: Aaron Cox Oct 26 2004, 05:19 PM

ouch <_<

Posted by: lapuwali Oct 26 2004, 05:31 PM

No, there is no absolute good v. bad in MAP v. MAF. For some uses, MAF is superior. MAP is better suited to being adapted to a wide variety of engines, and it a bit better suited to wilder cams. The Megasquirt stuff is all MAP based, as is SDS and nearly all of the other aftermarket units.

Posted by: fiid Oct 26 2004, 06:11 PM

Not at all. MAP is a suitable approximation for most systems, and I have found it to work pretty damned well. It's not so hot on engines that

Similarly - carbs work for most systems.

Something doesn't have to be perfect to be better. Better is good. Next week there will be something better than todays better. Technology is just about continuously trying to better what is there today.

I have a lot of respect for the work both you and Dave have done - it's top notch stuff. Please don't take what I am sayin' as dispectin'.

Posted by: Jake Raby Oct 26 2004, 06:22 PM

To be worth a damn, a system has to be simple! Too much crapola and bells and whistles sells things but that don't keep them on the road.

Dave has done an excellent job on his system, I can say that from first hand experience and 5,000 miles of proof.