The lost secret bosch knowledge!

#1

First of all I haven’t done this to my spec car.

The old motronic 1.1 had a fuel quality switch which could advance or retard timing, lean or richen fuel. The 1.3 ecu does not have this because it can be changed by a bmw technician using a computer. Our ECU has multiple maps in it including one tuned for premium fuel only. This would be legal if I could actually find a tsb relating to it. My brother discovered this by chasing rumors of the mythical +30hp euro tune while at bmw step school in New Jersey. I’m sure the power gain isn’t that much but that was the rumor.

We tried this back in 2004 when I was autoxing my 87 325is in stx. It resulted in a loss of 13 hp on a mustang dyno and fouled spark plugs. We think that the error was that we selected no catalytic converter on the computer, which I now don’t think was available in any market. The reason for the loss of power was a afr of 8.5 at full throttle. I think if we reprogrammed the ecu again and only changed it to premium fuel only euro spec we would gain hp, or being in Wisconsin I can legally tune with my ethanol content to accommodate the rich mixture.

My point is that a ecu tune/chip rule is unenforceable because I don’t even need to take the ecu out of the car to change the tune. I have also bought a chip on ebay for 25$ back around the same time, so why do we go through the heartache of chip checking.

I have been debating whether to tell the group about this for a least a year.

#2

Wow. That’s major stuff. I’m full of questions but no good would come from public answers so I might as well hold my tongue.

My guess is that we’ll ultimately have to have a dyno standard. The directors looked at this hard a couple years ago but couldn’t reach a decision. Give the dyno limit decision to whoever it was that summarily presented us with the new tires, and we’ll get a decision in a couple minutes.

#3

I’m against a dyno rule. It’s just another way for someone to get a surprise dq. I would prefer a little bit of ingenuity as long as it stays cheap. There is only so much power our car’s can make at .5mm overbore and our little valves and cam. That should be the limit.

A rule that is difficult or costly to enforce shouldn’t exist. Taking our cars to the dyno to make sure they are legal would cost more than a chip.

#4

Wow this shows how much of a rookie I am at these cars, but may explain some stuff from nationals. Thanks for posting. This is interesting.

#5

[quote=“turbo329is” post=68278]I’m against a dyno rule. It’s just another way for someone to get a surprise dq. I would prefer a little bit of ingenuity as long as it stays cheap. There is only so much power our car’s can make at .5mm overbore and our little valves and cam. That should be the limit.

A rule that is difficult or costly to enforce shouldn’t exist. Taking our cars to the dyno to make sure they are legal would cost more than a chip.[/quote]
It’s very hard to make >160hp or torque. There’s only a couple folks here that have played around with engines and engine management more than I have, and I’m here to tell you that >160 is very hard. So no one is going to make it by accident and then get surprised at the dyno.

Back when we were talking about a dyno standard, the number being thrown around was 165, but I’d be cool with 160. That would scale back the efforts of a few that are determined to get as much power as they can. Don’t get me wrong, I’m not speaking ill of them, I’ve a long record of being determined to do , then determined to do , so I can certainly relate.

I’m not saying everyone would have to get a dyno run recorded, altho we certainly could all do that at Balanced Performance at the first RA event of the year. Maybe we could just have say something more ambiguous like 160hp on a Dynojet is the max allowable hp and torque. That phrasing would regional directors a lot of freedom on how to enforce it. Mid-Atl has it easy because of the dyno at VIR. Tougher in the SE. Maybe if someone complained about a SE car, Robert and Chuck would find a way to get it to BP’s dyno not too far from RA.

Or how about this idea?.. Allow everyone to run a chip. Chip’s are cheap, I’ve had a Turner chip and a Dinian chip for sale for $75 for a year at bf.c and no one’s bought them so $$ is no big deal. Knock-offs are available on ebay for beer-money. The only chip that is a little more expensive is to get one that is customized to have the OEM red line.

We can’t stop people from chipping their DME. Anyone that thinks otherwise is wrong. I can put an illegal chip into a DME and you can’t tell. Since that’s the case, why not let everyone do it?

#6

At nationals most of us only made around 150whp give or take a little. The highest number was 156whp.

#7

I don’t think that a dyno standard is a good idea. Peak HP and TQ don’t tell the whole story.

But, if these ECUs can be tweaked without cracking the case, then something does need to be done in the rules.

#8

How can you change the tune without even taking the ecu out of the car?

#9

Y’all, you don’t worry about peak hp…what you want is area under the curve, and to get rid of the dip at 4500rpm. You can do that with a chip, but it would have to be tuned to your car. I don’t think a general tune would work.

Dynos at the nats were 150-156…all the same day. Therefore, consider them good numbers. We are racing cars, not dynos. If yours shows 160hp great…but it does not compare with the results at the nats. CB

#10

[quote=“cbullard” post=68297]At nationals most of us only made around 150whp give or take a little. The highest number was 156whp.[/quote]That’s an important point. It’s telling us that the status quo isn’t broken. Therefore we should pause and consider before advocating fixes.

My father used to tell me “Scott, if it ain’t broken, don’t fix it”. Generally when I ignored his advice, I later had cause to regret it.

#11

Highest was 157, lowest was 145

#12

[quote=“Ranger” post=68290]

Or how about this idea?.. Allow everyone to run a chip. Chip’s are cheap, I’ve had a Turner chip and a Dinian chip for sale for $75 for a year at bf.c and no one’s bought them so $$ is no big deal. Knock-offs are available on ebay for beer-money. The only chip that is a little more expensive is to get one that is customized to have the OEM red line.

We can’t stop people from chipping their DME. Anyone that thinks otherwise is wrong. I can put an illegal chip into a DME and you can’t tell. Since that’s the case, why not let everyone do it?[/quote]

That’s what I’m saying.

#13

What about sealing the ecu and/or the port?

#14

What happens if you had what I have and discover mid season that the ECU has a limiter and you need to source a new one?

#15

Fire gear on…

I’ve known about the switch in a 153 and the reported ability to soft switch a 173 (or later) for a long time. But I have studiously avoided mentioning it (or playing with it) because I think that would not be in line with the spirit of the class. And there are other ways to cheat that won’t be caught unless the inspector knows exactly where to look. And if done correctly won’t be caught by a dyno session.

In one sense this is a case where a MegaSquirt with a “standard tune” and data logs could potentially level the playing field with respect to the engine management system. All it takes is a laptop to download the tune and run an md5sum to tell if the tune is “standard”. A peek at the data logs will tell if sensor inputs have been fiddled with.

But really, if the engine is actually legal a proper tune has an upper limit that anyone can reach. And pretty economically. We are racers and want to get the most out of what we are allowed to run. And for the most part we are talking about 20’sh year old sensors and electronics. Fiddling with the parts used can have a noticeable affect on performance. It makes more sense to me (and is probably cheaper) to allow folks to tweak the tune.

Now back to our regularly scheduled programming…

#16

I believe the quick fix would be to unplug you’re speedo sensor.

#17

I believe the quick fix would be to unplug you’re speedo sensor.[/quote]
Only very late DME’s had a speed limiter, in which case disconnecting that input would disable it.

#18

I believe the quick fix would be to unplug you’re speedo sensor.[/quote]

Where do the rules say you can unplug the speedo sensor?

#19

The rules (9.3.13.14.1) allow for removal of the instrument cluster, cruise control, and OBC and allows for use of DME’s that don’t implement the speed limiter. Thus it would be reasonable to say that disconnecting the differential speed sensor, that serves no other purpose than to provide input to those, is legal.

#20

Just richening the motor won’t get you where you want to be. You must dyno tune the motor with timing and mixture…the timing curve is not what you would see on a normal motor. It goes up and down with rpm and mixture. Takes a while to understand what the motor wants. Chuck