m104 turbo project (c280) - Page 3 - PeachParts Mercedes-Benz Forum

JayRash · #31 06-13-2008, 05:11 PM

Quote:

Originally Posted by Joreto

what I mean is that every other pulse goes to each turbo i.e firing order 1-5-3-6-2-4 so in a twin setup instead of all pulses going to one turbo they are split up, 1-3-2 -> in one turbo and 5-6-4 -> into the other so in essence you have half the pulses/power to drive each turbo .

Ok true about having half the pulses, but the use of 2 small turbos on a large capacity engine really more than makes up for that. But even if you run higher boost (0.9) on the twins you will not believe how fast the spool up. The first few days after installing my twin T kit I ran at 0.9 bar and I had 0.5 bars from as low as 2200 rpms and full boost from 3000 up.

Twin turbo kit advantages:
-Quick spool at very low rpm
-Very little charge heat; as each turbo only has to boost half the total boost.
-Turbo life and reliability increased due to less working stress.
-Silent aural effect (if u want to keep things on the low side)
-On low boost setup (0.5 bar) you can run without a BOV with less risk of affecting the turbos as each one is spinning slower and the back charge divided on both.

Twin turbo kit disadvantages:
-Complex piping needed on all counts (oil, filter, water to turbo, intercooler, and down pipes)
-Tighter fit especially with the mosselman turbo arrangement
-Slightly more engine compartment heat generated as exhaust charge has to go thru
a smaller hotside.
-Slightly heavier setup

c280nz · #32 06-13-2008, 07:37 PM

Quote:

Originally Posted by rbycc

along with professional tuners and manufacturers tend to disagree with you...

On a small displacement low revving motor twin turbos produce more useable power and are more efficient then a single large compressor....
No one has used a single turbo in the last twenty years with any success.

Only to look at the new BMW 335 engine.

You start to spool up at 3000 rpm and get 5 psi boost at 3500...

I spool up at 1500 rpm and get full boost ( .5 bar ) at 3000 rpm.

You retard timing to prevent detonation which sacrifices power whereas I advance timing with no detonation and increase power.

A Merc I6 is a motor that should produce more torque then HP...
The lower rpm you achieve max torque ( I max at 4250 rpm ), the faster the car will be.

-----------------------------------------------------------------------
thankyou for repeteadly making it sound like i have no idea what im doing,
im starting to get sick of it -brother-

its all down to what suits you, i dont need boost that low, as to start with when i am crusing at 100-120kmph my car revs at 2250-2500rpm in top gear,
so the boost is right there let alone if i chop down a gear or two,

the single turbo i have no were near has the drawbacks to make me think omg i should have gone with 2 for the extra torque i will get in the 1500-2500rpm mark, i dont drive down here what so ever, infact my car is running in the 4-6500 mark most of the time as i just change up and down the gears to suit, even aftermarket tuners have compromises, normally based around being able to sell the units, and driveability and power availibilty off the bat is normally a criterior to try and keep -all users- happy,

when i put the car on a dyno i will post up the sheet, and i think it will show that my car is producing good torque and hp figures,
and imo i feel that the single turbo on my car is a success,

after i made my post the im starting to boost at 3 and generating 5psi at 3500, on the way into town last nite i gave it a boot in 4th gear and it started heading into the positive at 2500, and was at about 6psi at about 3100rpm,
and you say u develop max torque at 4250, well im producing good boost well before that. and it pulls very hard from there all the way to rev limit.

-both twin and single have there merits and drawbacks, i have chosen a single so lets lay off that debate in my topic now ok peps-

as you will know there are four main variable contributors to detonation to contend with, a.f ratio, charge air temp, fuel quality, and ignition timing

out of all of these the one which is limiting me at present is the a/f ratio, i cannot get it into the magic area of 12.5:1 wot, and it is leaning out, hence i have retarded the igniton timing at present by 6 degrees (i can easily run it more advanced but are playing it safe until i get my a.f ratios down lower, which i need larger injectors to do.
at present i have 310cc injectors, my standard ones were 200cc
and i am going to get injectors in the 400cc range,

in comparison for injector sizes
nissan skyline gtr 2.6ltr straight six 280hp at the fly 440cc injectors factory
toyota supra 2jz 3ltr straight six 280 hp at the fly 440cc injectors factory

JayRash · #33 06-14-2008, 02:40 AM

Quote:

Originally Posted by c280nz

-----------------------------------------------------------------------
thankyou for repeteadly making it sound like i have no idea what im doing,
im starting to get sick of it -brother-

its all down to what suits you, i dont need boost that low, as to start with when i am crusing at 100-120kmph my car revs at 2250-2500rpm in top gear,
so the boost is right there let alone if i chop down a gear or two,

the single turbo i have no were near has the drawbacks to make me think omg i should have gone with 2 for the extra torque i will get in the 1500-2500rpm mark, i dont drive down here what so ever, infact my car is running in the 4-6500 mark most of the time as i just change up and down the gears to suit, even aftermarket tuners have compromises, normally based around being able to sell the units, and driveability and power availibilty off the bat is normally a criterior to try and keep -all users- happy,

when i put the car on a dyno i will post up the sheet, and i think it will show that my car is producing good torque and hp figures,
and imo i feel that the single turbo on my car is a success,

after i made my post the im starting to boost at 3 and generating 5psi at 3500, on the way into town last nite i gave it a boot in 4th gear and it started heading into the positive at 2500, and was at about 6psi at about 3100rpm,
and you say u develop max torque at 4250, well im producing good boost well before that. and it pulls very hard from there all the way to rev limit.

-both twin and single have there merits and drawbacks, i have chosen a single so lets lay off that debate in my topic now ok peps-

as you will know there are four main variable contributors to detonation to contend with, a.f ratio, charge air temp, fuel quality, and ignition timing

out of all of these the one which is limiting me at present is the a/f ratio, i cannot get it into the magic area of 12.5:1 wot, and it is leaning out, hence i have retarded the igniton timing at present by 6 degrees (i can easily run it more advanced but are playing it safe until i get my a.f ratios down lower, which i need larger injectors to do.
at present i have 310cc injectors, my standard ones were 200cc
and i am going to get injectors in the 400cc range,

in comparison for injector sizes
nissan skyline gtr 2.6ltr straight six 280hp at the fly 440cc injectors factory
toyota supra 2jz 3ltr straight six 280 hp at the fly 440cc injectors factory

Sir, plz lets not get annoyed with each other here, personally I am not here to instruct or teach any one, the whole point of a forum is to maximize info flow. Any way I am sure that a single turbo setup is not bad at all, in fact it has many merits and if I had the option to choose ill be going that way, especially if one intends to boost around 11 psi u can custom fit a turbo from the Mitsubishi evo cars. Those turbos will spool on a 3.0 from as low as 1800 and will surely deliver 0.5 bars (8 psi ) from as low as 2500 rpms. If I am to run such boost levels that’s the only option I will go for.

RBYCC · #34 06-14-2008, 07:42 AM

Quote:

Originally Posted by c280nz

-----------------------------------------------------------------------

as you will know there are four main variable contributors to detonation to contend with, a.f ratio, charge air temp, fuel quality, and ignition timing

out of all of these the one which is limiting me at present is the a/f ratio, i cannot get it into the magic area of 12.5:1 wot, and it is leaning out, hence i have retarded the igniton timing at present by 6 degrees (i can easily run it more advanced but are playing it safe until i get my a.f ratios down lower, which i need larger injectors to do.
at present i have 310cc injectors, my standard ones were 200cc
and i am going to get injectors in the 400cc range,

in comparison for injector sizes
nissan skyline gtr 2.6ltr straight six 280hp at the fly 440cc injectors factory
toyota supra 2jz 3ltr straight six 280 hp at the fly 440cc injectors factory

With all due respect..it's obvious you have a fuel enrichment problem, can we agree on that?

The methods you are trying to resolve the boost AFR will cause other problems.

The stock injectors are just fine if you can cycle them enough.
It's not a mechanical problem but a control problem.

The larger injectors will potentially create idle problems and low speed driveability issues.
Just common sense...

The combination of the larger injectors and a higher fuel pressure regulator will strain the fuel pump and could even reduce high rpm flow.

Resolve your problem with control....no need to reinvent the wheel based on what a Japanese engine uses...

c280nz · #35 06-14-2008, 08:15 PM

Quote:

Originally Posted by RBYCC

With all due respect..it's obvious you have a fuel enrichment problem, can we agree on that?

The methods you are trying to resolve the boost AFR will cause other problems.

The stock injectors are just fine if you can cycle them enough.
It's not a mechanical problem but a control problem.

The larger injectors will potentially create idle problems and low speed driveability issues.
Just common sense...

The combination of the larger injectors and a higher fuel pressure regulator will strain the fuel pump and could even reduce high rpm flow.

Resolve your problem with control....no need to reinvent the wheel based on what a Japanese engine uses...

and yes the biggest concern i have will be idle/cruise problems, but i am going to have to see i guess, for these reasons:

now as u say to the problem
that is what i need to fix, and you have added valid points for me to think about regarding my afr problem,

my computer (greddy) i have at present i have set to max the whole way thru the rev range, i am able to vary my maf sensor signal by -50 to +50 %
and at present i have it set to +50% from 0-6500rpm

i have also changed my airflow meter to a larger one, which has narrowed down the scale thus i can set it to +50 to get it to to run ok, now my thinking is with larger injectors i can reduce the signal to down round 0 or into the negatives at lower revs and at low throttle positions,
at present if i reduce the signal any lower the +50 it runs way way to lean the whole time even at idle,

my greedy lets me adjust my airflow input in a 16*16 table based on throttle position and revs, and it also has a idle control function, which i am not using at present cos i dont really have a idle problem.

so basically with larger injectors i can reduce the maf reading at the lower end and increase it at 80- 100% throttle from about 3000-6500rpm.
u understand my thinking?

and "in my oppinion" i do not think my stock injectors are fine if i cycle them enough, it is reccomended to not cycle injectors higher than 85% at this level with a afr of 12.5:1 with 300cc injectors will produce 294hp based on the fuel they can inject.
i am happy with leaving the factory computer to control the max duty cycle of the injectors and just run bigger ones.

my local dyno guy says even if i had a full stand alone computer(giving total injector control) my injectors are far to small to make any decent power
-to make power you need fuel

RBYCC · #36 06-15-2008, 03:02 PM

Quote:

Originally Posted by c280nz

and yes the biggest concern i have will be idle/cruise problems, but i am going to have to see i guess, for these reasons:

now as u say to the problem
that is what i need to fix, and you have added valid points for me to think about regarding my afr problem,

my computer (greddy) i have at present i have set to max the whole way thru the rev range, i am able to vary my maf sensor signal by -50 to +50 %
and at present i have it set to +50% from 0-6500rpm

i have also changed my airflow meter to a larger one, which has narrowed down the scale thus i can set it to +50 to get it to to run ok, now my thinking is with larger injectors i can reduce the signal to down round 0 or into the negatives at lower revs and at low throttle positions,
at present if i reduce the signal any lower the +50 it runs way way to lean the whole time even at idle,

my greedy lets me adjust my airflow input in a 16*16 table based on throttle position and revs, and it also has a idle control function, which i am not using at present cos i dont really have a idle problem.

so basically with larger injectors i can reduce the maf reading at the lower end and increase it at 80- 100% throttle from about 3000-6500rpm.
u understand my thinking?

and "in my oppinion" i do not think my stock injectors are fine if i cycle them enough, it is reccomended to not cycle injectors higher than 85% at this level with a afr of 12.5:1 with 300cc injectors will produce 294hp based on the fuel they can inject.
i am happy with leaving the factory computer to control the max duty cycle of the injectors and just run bigger ones.

my local dyno guy says even if i had a full stand alone computer(giving total injector control) my injectors are far to small to make any decent power
-to make power you need fuel

Understand fully what you are trying to do, and you understand the problems that the larger injectors will create at low rpm.

The stock injectors will make more then enough power....Willy Mosselman proved that in hundreds of installs dating back to the late 1980's.

Mosselman used his own proprietary piggy back unit which the design is long lost.

So effective it was in contolling the stock injectors that one automatic car tuned by who I considered the last expert on boosting the I6 Mercs ran sub five second 0-60 and 11.98 second 0-100 with an automatic transmission and a 3.67:1 rear gear.

This was documente in the August 1987 issue of Autoweek....

How fast do you expect to go when complete ?

c280nz · #37 06-15-2008, 04:42 PM

it was my understanding that the molesman kit simply run a rising rate fuel pressure regulator, or as they call it fmu, this unit simply raises the fuel pressure under boost at a rate greater than 1:1, normally they ran them around 6-10:1 eg 1 pound boost raised the fuel pressure anywere from 6-10 psi higher than standard, is this the system u talk of? its the system they also used in other turbo kits i have read of, and was a very comon and cheap way to add more fuel under boost before more comon tuning ecus became available.
i used to run a 3.67 rear and have changed to a 3.27 so my first and second and third gear actually last a decent length of time between shifts because the manuals in benzs arnt the fastest changers.

autos with power can normally run faster 1/4mile times as they can get traction off the line, and do u know if he stripped the car down at all,
acceleration is based just as much on weight as it is power.

so when u also say stock injectors, are u meaning the 200cc injectors my car come with?

using the gear i have the only way simply to add more fuel is larger injectors,
at cruise conditions i hope the feed back loop with the standard o2 sensor should handle this (closed loop)
and at idle the idle control module on the throttle body,
i changed from 200-300 using my greddy with no noticable difference in both of these areas as to the cars function and usability.

300EVO · #38 06-15-2008, 04:56 PM

Not being a turbo expert in any way, and understanding that c280nz says he is happy with how his system operates for him in the rpm ranges he uses most, I was just curious how much of a difference it would make to change his 6 into 1 exhaust manifold which he has a picture of in his first post into a "split pulse" set-up like Roman(Pumpish) uses?

In other words, 3 cylinders feed half of the manifold flange at the turbo and the other 3 cylinders feed the other half. It's my understanding that this will produce some improvement in getting the turbine spooling faster by keeping the exhaust pulses tightly bundled in a single turbo application.

Does anyone have any practical experience on this?

P.S. and my apologies.....not intending to derail the current topic of the enrichment problem.

RBYCC · #39 06-15-2008, 06:22 PM

Quote:

Originally Posted by c280nz

it was my understanding that the molesman kit simply run a rising rate fuel pressure regulator, or as they call it fmu, this unit simply raises the fuel pressure under boost at a rate greater than 1:1, normally they ran them around 6-10:1 eg 1 pound boost raised the fuel pressure anywere from 6-10 psi higher than standard, is this the system u talk of? its the system they also used in other turbo kits i have read of, and was a very comon and cheap way to add more fuel under boost before more comon tuning ecus became available.

Mosselman used an analog piggyback setup which set the fuel trims with potentiometers....similar to the old ERL Aquamist unit.

Neither Mosselman or Turbotechnics did anything with the fuel pump(s), or regulator.

The piggyback electronics tended to run rich at lower RPM in order to run rich under boost.
There were some cold start problems and not the greatest idle.

Turbotechnics uses either 2 additional injectors ( M103 ) or 1 additional injector (M104)
Their supplied digital electronics also doesn't enrich enough for power, but in the late eighties and early nineties that was the best technology.
TT compensated by using a Hobbs switch to retard timing under boost to prevent detonation.

The use of a stand alone state of the art additional injector controller like the Split second AICI1 unit allows the stock control to remain stock, not even knowing that the engine is boosted.
The two stand alone additional injectors control the enrichment under boost.
The enrichment map is set via computer software and is 3d mappable.

Perfect for a street car, passes all emission tests and comes alive around 1500 rpm.

After much trial and error, whether twin small compressores or larger single unit, the additional injectors are perfect to achieve the 12.5AFR/.85 lambda.

You have great fabrication abilities, how hard would it be to add one or two additional injectors ?

Quote:

i used to run a 3.67 rear and have changed to a 3.27 so my first and second and third gear actually last a decent length of time between shifts because the manuals in benzs arnt the fastest changers.
autos with power can normally run faster 1/4mile times as they can get traction off the line, and do u know if he stripped the car down at all,
acceleration is based just as much on weight as it is power.

The car I mentioned was not stripped down it was a 1988 300E sedan with the M103-12V.

In the USA very few manual shift Mercs.
I only ran once, in very cold weather ( 3 degree C ) using 245/40-18 Falken FK-452's with 24psi.
Impossible to hook up with my automatic M103 with the stock 3.07 gear.
First run, launching at 1500 rpm, smoked the tires for an 1/8 mile.
Took 19 seconds to do the quarter, but it trapped at 90 mph.
Second run, idled off the line...still broke loose but 14.39 and 99mph.
With traction I see mid to high 13's and low 100's.

The car makes an incredible amount of torque, much more then my 1999 C43.

Dyno'd at a meager 208 hp and 228 lbft torque on a Mustang load dyno.
Car showed a 30% drive train loss from base stock to boosted.

Add that back and you're at 297 hp and 325 lbft at the crank.
Throw in the 14% differential between a load and an inertia dyno and you get: 345 hp and 377 lbft torque.

Just numbers, but with traction running a low 100mph trap in a 4000 lb coupe ( car + driver + gas ) and it about confirms the crank hp.

Quote:

so when u also say stock injectors, are u meaning the 200cc injectors my car come with?

In my case stock meaning the ones the car was delivered with in May of 1988...just changed out the seals.

Quote:

using the gear i have the only way simply to add more fuel is larger injectors,

Quote:

at cruise conditions i hope the feed back loop with the standard o2 sensor should handle this (closed loop)
and at idle the idle control module on the throttle body,
i changed from 200-300 using my greddy with no noticable difference in both of these areas as to the cars function and usability.

Going back to the additional injector control it's simplistic...
Has a built in MAP sensor, so vacuum line to the intake manifold, +/- 12VDC power, speed signal from tach and pulse signal to the additional injectors.

Admit being skeptical to how well the fuel distribution would be with the additional injectors...but the distribution to each cylinder is about as good as it gets !!!

RBYCC · #40 06-15-2008, 06:30 PM

Quote:

Originally Posted by 300EVO

Not being a turbo expert in any way, and understanding that c280nz says he is happy with how his system operates for him in the rpm ranges he uses most, I was just curious how much of a difference it would make to change his 6 into 1 exhaust manifold which he has a picture of in his first post into a "split pulse" set-up like Roman(Pumpish) uses?

In other words, 3 cylinders feed half of the manifold flange at the turbo and the other 3 cylinders feed the other half. It's my understanding that this will produce some improvement in getting the turbine spooling faster by keeping the exhaust pulses tightly bundled in a single turbo application.

Does anyone have any practical experience on this?

P.S. and my apologies.....not intending to derail the current topic of the enrichment problem.

Very true because you're not trying to run past the prior pulse....
Same for twin downpipes which give better scavenging.

In essence that's what the small twin compressors do...looks at the engine as two three cylinders and spools up around 1500 rpm with zero lag and turbine like smoothness.....

Can't even hear the turbos...only at low speed when you let off the peddle you'll get a slight hoot...