I guess I should try to clarify a couple of things. First why tune without an 02. sensor. Firstly, I build analogue controllers that actually respond, from birth so to speak, to the manifold pressure and rpm of the engine; unlike the processor based controller, which doesn't doanything until it get some kind of instructions. Secondly; bcause you can! Remembering that these are no-smog applications we're discussing; the fueling requirements are not as critical as you seem to believe; if it`s a little better then a carburettor at idle and part t hrottle cruise; we`ll say, a little more accurate than an old style oem carb. than that's good enough! There's always such a consideration as good enough. it's fundamental to engineering. If you actually do this; tune up your car without your 02closed loop turned on; you'll be pleasantly surprised; it's easy enough and the car works fine. The thing is, we're really not launching a rocket at the moon! Dave Vizard wrote a series of books about tuning and engine modifications, and included an example of a v-8 pickup truck engine with four double barrel downdraft carbs. that he tuned up' ; it delivered efi like economy a very broad torque band and very high peak horsepower. I would not like to have the job of improving on any of the numbers he achieved even with a $10,000 parts budget for any kind of efi equiptment I wanted to buy. This is an opinion; but I think I might still be trying to succeed next year. The best that the best carburettors can do, in the hands of a master engine builder and tuner, which he is; overlap the performance of a modern efi system. Providing fuel to the engine is not nuclear physics, and we have a fairly broad target to aim at. The OEM's live in a different world then the person modifying his non-smog car; they have to have extreme fuelling accuracy and weird timing curves to force the cats to work and make the smog numbers. One really good reason not to use your 02 loop is that any modern engine with a good ignition system, will run at 15.5 to one at cruise power, instead of 14.7; only experiment will reveal what your engine will do, but 16 to one 8psi manifold pressure; say maybe, rolling along at 55 on the road will be feasible for many engines; fuel economy. Of course the mixture snaps back to 13 when you put your foot down. Some people start out every year to do these conversions; and as you say, correctly, ifyou don't know anything, you may fail. I felt that I should provide a reminder of this to people who want to do this; read some literature first, you know; that kind of thing. You know a lot about this, you're technically sophisticated, you handle math and numbers easily; but consider how many people there are for whom this is not true? Oh well, I hope I haven't got myself evicted already. I better shut up and go to bed. cheers, jack.

If you know what Warren Johnson wants, you know more than I do. As far I know he wants to retire; and I don't blame him. They use four barrel carbs., specifically; because of the NHRA rule book. Wally Parks owns the NHRA; he was its originator; he put the four-barrel carb rule in there because he bought a lot stock in Holley Carburettor co. This is a matter of historical record. You assume that there's a "huge advantage" to be gained in this racing class by converting to efi. This is a false assumption. Think about the underlying process; air and fuel. that's it. there''s no magic. The huge advantage, for these engines, You picked the worst possible example, doesn't exist; The money you refer to is spent getting the things to inhale another 5 or 10 lbs of air a minute; and not have mechanical failures. In the extremely unlikely event that NHRA decides to make this an EFI class; small increments in power, and tiny increases in performance numbers will result. EFI racing classes exist, now. Mostly outside the NHRA, which now has competitor sanctioning bodies, as they're called. Race engine EFI tunersexist. Persons exist who have made the transition from carburettors to EFI, with the same engine; with the same size engine. They have spoken for publication; What do they say; only small increments of improvment are possible; main advantage, consistency' which is very important to be sure. Huge performance changes; uh-uh. Going to happen in the future, with "better EFI"; no, fraid not. This is a mature technology. the appropriate mixture is being delivered; that's it. there's no more, there's no magic. Actually I fuel injected a drag race car that makes a very good case study, because nothing changed except this. I replaced the four=barrel carb. with a 16" HIGH straight piece of 3" exhaust pipe, straight up through the hood containing the usual butterly throttle near it's lower end, the lower end of the tube was welded to plate so it could bolt on to the manifold in place of the carburettor. Injector bungs were added to the runners on the Edelbrock Victor manifold. Several factors came into play here; the combustion air now comes from the free air stream above the hood, instead of the hot air under the hood; some ramming effect is available; and because the mixture was adjusted with one little screwdriver adjust on the dashboard; the mixture could actually be optimized. There's no dyno, available; you have to take the car to the race track on a trailer and do your mixture fiddling there; this is such a long and irritating, (stupid), thing to try to do; that it usually doesn't get perfected; not in our little amateur classes. These factors added up to 43hp. improvement on a 445hp engine; and it was very consistent. Most of this improvement came from the snorkel; only a little of it from the easily dialed-in mixture.A conventional person who bought a throttle body for the manifold and put injectors in it; wouldn't see anything like 43hp. A few horsepower could be gained by going to individual cylinder controll, but not much. and that's it. It's a machine' it burns air and fuel; once it gets the right amount of fuel full power; it's done; there's nowhere to go. Obviously, the full spectrum of modifications are still available; but as far as fuel injection goes, that's it. To look for 35hp. from a small, good breathing engine, as a result of changing the fuel delivery method, is like looking for rain to fall out of a clear blue sky< a spanish proverb I'm fond of> I hope this helps to clear things up. Cheers Jack.

The post I keep trying to refer to is #18 reply to the Dan16V thread about the completed throttle bodies. This guy did convert his engine and he tells you what the result is. My experience with human beings indicates that "not much", as the result of their very own modification program, means "nothing". A lot faster; means 12hp. etc. ho ho ho. cheers, jack.

Some questions: First, if ITBs are not going to give you more HPs, then why do they appear on so many performance applications? The original M3, any ferrari that comes to mind along with many modern supercars all have them. If there is no advantage, why do the manufacturers spend the $ on them? Note that the engine that dan16v was working on also had ITBs that the factory put on when it was entered in the DTM series (see the picture). Again, why is this the case if there is no performance gain?

The same thing goes for EFI in types of racing that are not restricted. Do F1 teams choose carbs and distributors even if they have the chance to go distributorless and EFI?

Thanks for chipping in John, i've enjoyed your posts.

cheers,
dan r.

I sure hope I didn't say that individual runners weren't the way to go for peak horsepower; what I thought I said, was why have four throttles, eg. butterly valves, on the runners entering a pressurized plenum. What I thought the owner said was that he was building a turbo project. There's no controversy about individual runners, or stacks, or ITB's being the peak horsepower generaters in NA applications. It's possible that very advanced factory development teams have found some benefit to having individual throttle valves in the runners of their supercharged engines; I don't know. For the kind of stuff I deal with and the people on the forum deal with; performance street cars and bracket racers I'm sure there's nothing good there. There are hundreds and hundreds of highly supercharged cars around now-adays; I only see pictures of drag cars and hot street cars, but within that limitation I've never seen a turbo engine with individual throttles in the runners; and that includes the Japanese National Champion Drag car; some 1200 or so horsepower from a japanese DOHC straight six, (I forgot what brand it is). I'm not reccommending carburetors for any purpose; ok? What I do is convert cars to EFI and build the controllers for them. The mechanical distributor I touted as part of a conversion for a CIS MB with the toothed wheel business; is intended to one techno. generation earlier; mechanical advance plus electronic pickup or coil switch module; I'm not interested in ign. points! Admittedly, mechanical distributor is not clear, but that's what I'm trying to say. The only reason I mentioned this; elimination of the original spark angle controller, is that I have seen a failure; where the car still ran, but ewwuw. If I have seen one there are more out there. Also, it saves money, I would think. I just built a replacement controller for a 1979 Bosch EFI with the little paddle in the box air meter; and it was completely analogue, No processor. Trippy, huh. It lasted for a long time; but the components don't have the extreme long life of the modern chips. Fl cars? there aren't any 18500rpm 8 cylinder distributors; how's that for a reason? Be serious; that's a different world' but really they are constantly striving for fuel economy; I'm not making this up! My favorite quote from F1 world, "I work all year to make 4 hoursepower"; whoa. Too serious. Really now, you know why they have to have the most sophisticated engine controls, and so do I. My point is you don't need the most sophisticated engine controlls. Maybe everyone on this forum is rich; what do I know; I thought somebody might want to know that the simple controller and a distributor with mechanical advance will get the whole job done and not leave any horsepower crumbs under the rug; So you don't want to know; fine I shall remain silent. Thank you for your patience; I didn't mean to be so easy to mis-understand.

Heres a good article on a Mercedes 450SEL that was converted from CIS to EFI.

http://www.autospeed.com/A_0001/cms/article.html

"The Mercedes took a few days of (not continuous) work to program the ECU. At the end of this process a car drove out of the workshop that had a power gain of 17 per cent! This is partly the result of CIS mechanical injection airflow vane no longer obstructing the intake air path, and partly because the management system could be fine-tuned so well. Economy also improved!"

__________________
Current Stable:
01 ML55 AMG
92 500E (a few mods)
87 300E (lots of mods)
00 Chevy 3500HD Diesel Box Truck
68 18' Donzi Marine
06 GT i-Drive7 1.0 Mountain Bike (with GPS!)

PREVIOUSLY OWNED:83 300SD, 87 420SEL, 88 420SEL, 90 420SEL, 86 560SEL, 86 190E 2.3-16V AMG, 94 E320

John Affleck, thanks for your posts, they make interesting reading and have made me think again.

Do you know anything about the Kugelfischer fuel injection that the 16v engine was originally developed with (when it was being developed purely for racing)?

Can you recommend the best way to unleash some more power from the 16v engine? Given its development, design and capabilities (the 2.3 being initially developed to 320bhp specification and then detuned for the road), it seems like it should be capable of a lot more power - ideally still with a good torque curve - with the time and effort applied in the right place. I am wondering what that place is. I am confident it is not in the head.


Russell

__________________
190E's:
2.5-16v 1990 90,000m Astral Silver
2.0E 8v 1986 107,000m Black 2nd owner
http://www.maylane.demon.co.uk/190esmall.jpghttp://www.maylane.demon.co.uk/190esmall2.jpg

I'm afraid my local doesn't do courage pale jack!

__________________
190E's:
2.5-16v 1990 90,000m Astral Silver
2.0E 8v 1986 107,000m Black 2nd owner
http://www.maylane.demon.co.uk/190esmall.jpghttp://www.maylane.demon.co.uk/190esmall2.jpg

John.I´m the tuner Pento speaks of,and Pento it was 30+.Not 35.
Nevermind tho,as that´s besides the point to an extent.

John,much like you i happen to have a masters as well.
In my case as an aeronautic engineer,and yes,i do this crap with engines for a living.

Car we used was a bone stock(from intake filter box intake tip to exhaust tip)92 2,5-16.
Dyno-or rollers for that matter-are calibrated.
Granted..tires and what have you can slip,but in such a case i´d guess we´d have noticed as it´s not the first time out ever on a dyno.
First pulls done with the car was bone stock,and left us with 194,7.Close enough i´d say.
Car was converted in as much as that we gutted the fabled KE jet and installed an Omex and went at it.

I´d be happy to take a discussion on the matter from a pure tech standpoint any day.Seing is believing,and the OEM mercs are indeed setup extremely conservative leaving room for "easy" power gains.Think what you will.

What´s more is that if you insist on tuning out of loop with a current crop cailbrated LSU4 onboard you´re at least a zillion light years faster than i am as a tuner.This goes for electronic impliment of EGTs as well.One of the reasons for us being able to extract more power is that we these days rely on the electronics to get closer to the edge.

Next up tho i´ll be the first to sign the paper that states the sequential anything for the average enthusiast is a damn waste of time and space.
That is NOT the same as stating that sequential setup of fuel will not render power increase-cause it will.
When done right expect along the lines of 2-3% at WOT-but only,and i mean only,after many many many a long night in the dyno cell figuring out setup for everyting from injector placement to spray pattern and what have you.
Iow not something to chase for the average John Doe.

As for your comments on that anything is tunable.I agree.Een the POS KE-jet is.
Point is that it´s ANYTHING but cost effective,but if you wanna fool around with it until it drives you up the wall-be my guest.
IMO it IS a pos system that shoulda been abandoned ages ago.Hell,it was even outdated when these cars were new,and the 16vlv was supposed to be an avant garde car.?
Guess mercedes had their reasons for keeping it tho.

Dan btw.
Prime reason for using ITBs is that u will get improved throttle response and feel as the same amount of throttle movement will "release" much more freed throttle area.
Just stands to reason.

Therein also lies the nemesis of ITB tuning.To get the car "driveable" enough for the average public to deem(sp?) it so.
Power increase over e well thought out plenum design tho,no.
In fact,none what so ever.
At WOT you can´t very well get a VE higher than the engine will digest.
Sure,there are ways of increasing the VE above 100% through ram tuning(helmholtz asf),by using scoops to induce pressure above atmosphere asf.
None the less..that has nothing what so ever with the ITB setup to do.

Much as John also states the development of turbos has rendered the idea of ITB to more or less a halt.With a turbocharger up front there´s no need to take intake throttle areas asf into the equation in the same way anymore.
Take a look at the current era crop BBC engines inxs of 2500hp.
Most likely..you´ll find a couple of simple 80mm TB out front in the plenum.
Reasons for this are plentyfold,and if you wanna know let´s start another thread on the subject.

Btw.On the subject of intake pressure reduction.
Pressure drop is pressure drop.No matter what.
And it´s ALL bad in this respect.