Twin turbo 3.0 or 3.2 what size turbos for 400+ hp? - Page 2 - PeachParts Mercedes-Benz Forum

c280nz · #16 11-26-2008, 01:08 AM

get a manual box and anti-lag

and just chop thru the gears.

haha im just tryn to keep the debate going!

what about running a similar turbo to on your e320, how does that setup go?
very laggy?

whipplem104 · #17 11-26-2008, 01:43 AM

I would say if you want truly linear throttle with lots of power down low then use a supercharger. There is no lag and the power is very predictable and easy to control on the gas pedal.
If you are dedicated to a turbo set up then for the hp numbers you are looking for there is no reason that you cannot have almost full boost by 3000 rpm with a twin scroll turbo. I would think that you could actually have more even earlier. I work on an audi aan rallye quattro that uses a little turbo with a restrictor. This thing makes full boost [18lbs] by 2200 rpm and full torque as well. It would easily make over 400 hp without the restrictor and it is a 2.2l 5 cylinder. As mentioned here the mercedes v12 twin turbo makes full torque by 1800-1900 rpm. Cut that motor in half and you have a straight six.
If you wanted full torque by 1900 rpm and 800 hp then you would probably have to do something else.
Also for racing you could do a true bypass to keep the turbo rpms high while out of the throttle. Mercedes and I assume others now do this. Keeps the compressor from stalling from the pressure spike when throttle is closed.

JayRash · #18 11-26-2008, 03:11 AM

Guys, i have 2 KKK k-16 turbos spool is just ok, problem is if running low boost like am ie 8 psi, and since i dont have electronic control over the waste gates i have lag
its lag due to the fact that the waste gates are set for max opening , thus they open early and the boost eventually builds to max and holds when rpm increases.

i know not many have same issues, but i have to say for looks and almost stock style and for sound twin turbo is the way, as for power well it all depends on how far each is setup.
if am to chose now, i will go for a single turbo prolly one from the tommimakinen evo 6 turbos (seling new for around usd 1200).

That turbo even on a 2.0 4cyl engine has atleast 8 psi from 2200 rpm, its down to the wastegate control in the end though. cause on 1/2 closed wastegates my kkk had stunning spool at 2000 rpm

Joreto · #19 11-26-2008, 05:24 AM

Quote:

Originally Posted by PUMPISH

...... With a stock M103 engne you can easy rev 8000rpm if you want it.
7200 is normal if you choose Turbo for about 700-800hp

Do you mean that the stock valvetrain(springs, retainers ect.) has no problem handling 8000 rpm, would it be safe to rev a stock m103 with turbo to 7000-7200 rpm ?

As to single vs twin turbos, wouldn't a properly sized single give about the same response as a twin turbo, say a single matched to give the same power as the mosselman twin turbo ? I my opinion atleast the response time would be similar since the single turbo won't be very big and it'll have all the exhaust pulses going into it where as on a twin (setup like mosselman) every other exhaust pulse goes to one of the turbos. Also I think that most lag from the single turbos is caused by using very large turbos, say capable of 500hp-600hp when you only intend to put out say 350-400hp. To sum it up sizing is everything, for instance if mosselman intended the kit to be capable of say 500hp then the twins would have been bigger which would have
resulted in more lag

.

P.S.

Quote:

Originally Posted by RBYCC

.....Boost fixed at .48bar and AFR is 12.5:1 under boost.

Isn't the AFR a bit on the lean size? I know that .48 bars is not a lot of boost but I always prefer to tune to ~ 12.0:1 under boost just to be on the safe side (in case of say a clogged injector or so) . Also any idea what your total timing is @ .48 bars, I read that you pulled the resistor to get a bit of retard.

JayRash · #20 11-26-2008, 05:41 AM

Quote:

Originally Posted by Joreto

P.S.

Isn't the AFR a bit on the lean size? I know that .48 bars is not a lot of boost but I always prefer to tune to ~ 12.0:1 under boost just to be on the safe side (in case of say a clogged injector or so) . Also any idea what your total timing is @ .48 bars, I read that you pulled the resistor to get a bit of retard.

12.5 AFR i say is ok , Mosselman techs have told me to set up my car between 12 and upto 12.8. Any am runing at 12.8-12.9 in third at 6600 and its fine as long as the intercooler is cold and am at 0.5 bar +. but at 12.9 afr i am a bit lean to be on the safe side.

Pulling the resistor IIRC advances rather than retard the timing. i know this cause a fixed resistor is same as euro specs EZL R16/1 switch. that one has most advance on open circuit setting.

Joreto · #21 11-26-2008, 05:53 AM

Wow Jay, those mixtures are too lean in my book, 12.8-13 is where NA cars run. In my opinion with such lean mixtures you could end up with a blown head gasket (say a prolonged run under full boost when the engine builds up heat). Going leaner than 12.5 (under boost) is like pulling the tiger by the tail. Keep in mind that the performance gain of 12.8 over say 12.5 - 12.0 is not that big to risk the chance of detonation.

P.S. also the additional fuel could have a good cooling effect in the cylinders (give it's no overly rich...which could cause bearings to fail)

JayRash · #22 11-26-2008, 06:15 AM

Quote:

Originally Posted by Joreto

Wow Jay, those mixtures are too lean in my book, 12.8-13 is where NA cars run. In my opinion with such lean mixtures you could end up with a blown head gasket (say a prolonged run under full boost when the engine builds up heat). Going leaner than 12.5 (under boost) is like pulling the tiger by the tail. Keep in mind that the performance gain of 12.8 over say 12.5 - 12.0 is not that big to risk the chance of detonation.

P.S. also the additional fuel could have a good cooling effect in the cylinders (give it's no overly rich...which could cause bearings to fail)

well if it was up to me man i would run richer at the top, its the best i can do for now.
its like my wide band is linked to the rpm, the higher u go the eaner it gets. and yes i say prolonged runs at 13 will do havoc to ur HG. but i only run AFR of 12.5 and above from 5800 - 6600 rpm

any way i already have a copper HG for added life

keep in mind that am running the stock CIS and no extra injectors. finding parts here in Lebanon is not easy.

define overly rich, plz what AFR would be considered overly rich, and would short bursts of richness say AFR 10+ be considered overly rich

PUMPISH · #23 11-26-2008, 06:50 AM

Quote:

Originally Posted by Turbo E320

I wanted to use twins so I could have the power at lower RPM. I cant dance around at 6000 revs all through the track. At some points in this course you will be pulling out of a corner at 3000 rpm.

On the supra note, supras have become straight line cars and most big power single turbo setups on supras are lag monsters. Theres a 850hp black supra around here and it gets jumped by 400-500hp sti's when racing for a few moments before the turbo finally hits full boost.

Then I am sure this supra does not use twin entry.
I tuned several supras here with perfect range and no lag (ketchup)

I am allways trying to find turbostup to place max Nm so near as possible max Hp and that nm growing softly from the lower rpm.

My first setup on my car with no twin entry I had:
700nm at 3200rpm and 560hp at 5300rpm
It was like a bomb comming at 3200rpm and I was just spinning on all gears.

Next setup I had twin entry and even bigger turbocharger and I got:
780nm at 5800 rpm and 650Hp at 6000rpm.
Both Nm and Hp allmost at the same rpm.
The difference was amazing. Power was growing softly from about 2800-3000rpm and all the way up with no lag at all.
It was the same feeling like Cetrifugal supercharger, everybody sad it to me who got a tour with my car.

Last client we builded turbokit with TB60 and twin entry manifold and he got 480hp at 5000rpm and 630nm at 4700rpm.
Perfect range all the way from the 2000rpm with no lag at all.

But of course when we start talking 700-800hp++ then it become difficult to avoid lag, does not matter what do to hehe

By the way the boost controller is a good stuff to avoid lag and get better range. Increase boost with a same curve increasing the rpm and fifferent gears

PUMPISH · #24 11-26-2008, 07:09 AM

Quote:

Originally Posted by Joreto

Do you mean that the stock valvetrain(springs, retainers ect.) has no problem handling 8000 rpm, would it be safe to rev a stock m103 with turbo to 7000-7200 rpm ?

As to single vs twin turbos, wouldn't a properly sized single give about the same response as a twin turbo, say a single matched to give the same power as the mosselman twin turbo ? I my opinion atleast the response time would be similar since the single turbo won't be very big and it'll have all the exhaust pulses going into it where as on a twin (setup like mosselman) every other exhaust pulse goes to one of the turbos. Also I think that most lag from the single turbos is caused by using very large turbos, say capable of 500hp-600hp when you only intend to put out say 350-400hp. To sum it up sizing is everything, for instance if mosselman intended the kit to be capable of say 500hp then the twins would have been bigger which would have
resulted in more lag

.

Yeah! That was exactly what I was trying to say by comparing it with water!

1pcs 500hp = same= 2pcs 250hp turbochargers!
By using 2 turbochargers you can not make the engines pumping more exhaust and and the engine bigger size hehe

But advantage with a Single that you can use ign pulses becaurse turbocharger is made for pulses with a double and tight channels inside.
Then Single setup allowa more space for better manifold with longer and better tubes. And its more simple to make and working with.
I see only advantage with a single.
But like you sad, if you choose wrong (too big) Turbocharger for your setup then no twin entry manifold can save you

yes its no problem to rev 7200 with a turbocharger to be save.

I rev 8500 with my stock valvetrain allt the time and never had any problem.
I even tryed rev 10120rpm one time and then springs touched the pistons a little beat but nothing broke hehe
But you should check that springs are not too old. After 250k km springs getting old and lose tension

Dee8go · #25 11-26-2008, 08:58 AM

So, are you guys saying that smaller twin turbos spool up faster than a larger single turbo does? It would seem that this would counteract the lag problem common to turbos. Roman, does the pulsesplit you're describing accomplish the same thing in a single turbo?

RBYCC · #26 11-26-2008, 09:41 AM

Quote:

Originally Posted by PUMPISH

I knew that you would aswer with something like that.

The difference when I am writing something about tuning, I say things only I tryed by my self. I should never say anythiung about something I was reading or something I have heard somewhere.
1000 times I find out that it is big difference between teory and practise.

I work with turbochargers and tuning every day and it is the only thing I do and we compare stuff all the time. Different turbochargers, different engines.

I never sad anything about V8 TT.
I am talking about inline 4 and inline 6 and pulssplitt effect.

Where do you find that singel turbo gives a very small operating range?
Why it gives wider range at Supra MK4 then stock TT?

You should check more about pulssplitt/twin entry. Amazing stuff discovered ´for big heavy trucks so they can pull heavy trailers with early and soft range.
In sweden is very popular to use twin entry turbochargers and manifolds to avoid that we call here (ketchup effect) range.

Only in the little Stockholm we have more then 20 singel MK4 and everybody convert to single becaurse it gives much wider range.

Like twin entry so the Standalone system is popular too here in sweden and I had many tuning job last 4-5 month, about 40 different cars with different setups. So I have something to compare with.

Like I sad I should never say a word here about something I did not try by myself. And something I realy expiriment 100 times with is M103

By the way it is amazing how the turbochargering grows everyday.
We have a few guys here in town only 16-17 years old and allready making amazing stuff with a cars from the ground. Building own manifolds and installing Standalone and it looks like made by proffesional.

I don't speak about what I read about, but as you from personal experience over the years.
Currently I own a M103-12V twin turbo operatiing at only 7PSI.

I post below my meager dyno chart....RWP up about 5% from the below chart after a few intake mods were made. ( Mustang load dyno...90 deg F ambient )

The install dyno tune was done by an individual who probably knows more about turbo charging the I6 Merc then anyone in the USA.

Consider my RWP which is one third of what you may claim you are getting...but under timed acceleration runs it realized 0-100KMH in mid five second and 1/4 mile in high 13's at low 100mph trap.

This is with a car that has a gross weight of around 4000lbs with driver and fuel.

Traction is a serious problem and with drag radials low 13's are probable.
Change the rear gear from 3.07 to 3.67 and I'm low 13's..

My point has always been that there exists more then one path to performance.

I'm more a purist and prefer to create a "period" install and get the most from it by adding minimal new technology.

I'm satisfied with the performance of the KE, the car is extermely reliable and until you push the pedal down you wouldn't know it has a TT.

What kind of recorded acceleration times are you getting from your high boost motors ?
I would think not proportional to my low RWP install?

At some point you challenge the law of diminishing returns.
Drivetrain and chassis can't handle power it wasn't designed for...
Power that can't reach the ground and be controlled is like having no power..
What is the durability of your engines..
Both Turbotechnics and Mosselmann have installs on cars for almost twenty years + with some at 200K miles with no failures of engine internals...

RBYCC · #27 11-26-2008, 10:16 AM

Quote:

Originally Posted by Joreto

Wow Jay, those mixtures are too lean in my book, 12.8-13 is where NA cars run. In my opinion with such lean mixtures you could end up with a blown head gasket (say a prolonged run under full boost when the engine builds up heat). Going leaner than 12.5 (under boost) is like pulling the tiger by the tail. Keep in mind that the performance gain of 12.8 over say 12.5 - 12.0 is not that big to risk the chance of detonation.

P.S. also the additional fuel could have a good cooling effect in the cylinders (give it's no overly rich...which could cause bearings to fail)

12.5 / .85 lambda is what I found optimum on the Turbotechnics setup.
No detonation running 93 octane 10% ethanol ( not RON but USA PON = RON + MON /2 rating )

No overheating, engine in 35C + ambient stays in the normal operating range.

Plugs read a perfect light tan...

No need to enrich beyond a dyno proven and adjusted AFR.

Turbo E320 · #28 11-26-2008, 10:32 AM

On the AFR notes, mercedes makes a lean engine so its natural that even when modified they would run leaner than most. I accidentally did a full 3rd gear pullon the dyno with a AFR of 15:1(yikes) and the motor was completely fine.

Roman- I understand that these twin scroll turbos utilize the exhaust pulses more efficiently and can make big power but I really cant have my torque coming on at 5000 to 6000 rpm. I gotta have a lot of torque eariler like my e320 which is hitting 366 foot pounds of torque(about 470nm) at 3500.

whipplem104- I definately see your point on the supercharger. There is power down low in those and they respond much better if you have to "power clutch" the car to get the revs up. I will have to see what your setup makes this 2nd time around

c280nz- I run the same turbo as you

My automatic lags to 2300 unless I stand on the brakes and get the revs up.

RBYCC- I agree with you, I always thought twins would spool faster for lower rpm. This track has one straight at the front but after that its quite compact.

RBYCC · #29 11-26-2008, 11:06 AM

Roman....

How wrong was BMW in applying such outdated twin turbo theory on a new inline 6 cylinder engine application....?????

Looks like they were spot on......

"Best engine of 2007"....

"BMW wins third International Engine of the Year Award in a row

There is no question that BMW has some serious engine technology in its arsenal, and now those engines have more awards to show just how good they really are. BMW has won its third consecutive International Engine of the Year award, due this time to the incredible twin-turbo 3.0L inline six that resides in the 335i's engine bay. The 300hp (or more) motor combines blistering performance (car magazines report 0-60 times in the 4.8-5.1 range) with very good fuel economy and virtually no turbo lag. It won three awards in all, with the Bavarians also taking the trophy for Best New Engine and best 2.5L to 3.0L engine. "

JayRash · #30 11-26-2008, 11:08 AM

Quote:

Originally Posted by Turbo E320

On the AFR notes, mercedes makes a lean engine so its natural that even when modified they would run leaner than most. I accidentally did a full 3rd gear pullon the dyno with a AFR of 15:1(yikes) and the motor was completely fine.

Ma n i drove my M103 for over a week with no fuel after 4000 rpm, then after that drove it in a lean setup for a month where at top end rpm i was ranning AFR higher than 14, here in the end and after 4 full runs with pinging heard from another car i lost my 100K km HG. man mercs are built like nothing else , at least the M103. any way now am more forgiving on this engine and i do stop when something is off, especiallly that i have my wide band perm installed.