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

RBYCC · #1 11-24-2008, 09:16 AM

I run twin Garrett T2's which are no longer available.
Each compressor is piped to three cylinders using discrete manifolds.

The smaller turbos spool up extremely fast, no lag and are very quiet.
Boost fixed at .48bar and AFR is 12.5:1 under boost.

Two major players with the best experience on M103 and M104 Turbocharging were Mosselmann and Turbotechnics.
Both chose twin small compressores with low boost and required no modification to the engine internals or fuel delivery system.

As far as dyno numbers they are only a tuning tool givng before and after mod comparisions.
High numbers that are thrown around forums are usually for bragging rights and rarely backed up by any timed acceleration runs.

I pulled 230RWP on a Mustang Load dyno an increase of 100RWP over stock.
With stock 3.07 rear gear timed acceleration to 60MPH is around 5.5 seconds and 1/4 mile high 13's around 100mph trap.
Drag radials will bring the time to mid 13's...
This is on a 4000lb vehicle ( car, driver, fuel)

Don't build a high rwp hand greanade...build it fast but also reliable...!

Ortolan · #2 11-24-2008, 01:58 PM

I also run twin T2 units on my M104, however, due to the increased displacement (3.5L) and boost pressure (14psi) the engine is unable to rev past 5000rpm. The turbos just can't pass enough air though.
I was looking at twin GT25 units as a replacement to maintain the same fast spool & torque curve but allow the engine to rev to 8000rpm.

PUMPISH · #3 11-24-2008, 05:47 PM

who sad that twin turbo is better and give faster spooling time???

Each turbocharger getting exhaust from the 3 cyl each.

If you want to fill a tank with 10 liter water from the 2 small cans with a little holes of from the dobble as big can with a dobble as bif hole. It takes exatcly the same time.

BUT with a singel turbocharger you can stil use ignition pulses by using twin entry turbocharger and manifold wich gives you faster spool and much softer curve.

Buy ballbearing??? Total pointless.
We have tryed ball bearing on many different engines and mercedes engines and it does not give any faster spool. Only cost more money and more sensitive.

Our TB60 t3 divided 60mm inducer (600hp) starts spooling at 2000rpm (m103 engine) and pumping up to 6500.

TB70 t3 divided 70mm indiucer (800hp)
starts about 2300 and up to 6500

GT45 (900hp) starts at 3000rpm and all the way up tp 7000.

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

Turbonetics t61 is allmost the same size like our TB60 but much slower spoole becaurse of heavyer shaft

New TB60 is producing now and comes very soon

p.s. Even Supra MK4 makes much better and faster spool with a Singel Turbo convert then stock twin.

Twin turbo is something poeple belived at 80s and 90s was a best before they find out that Truck pulssplitt system and singel turbo is much better

c280nz · #4 11-25-2008, 02:32 AM

im with pumpish,

if your building a high hp road/race car big single is better.

RBYCC · #5 11-25-2008, 09:04 AM

Quote:

Originally Posted by PUMPISH

who sad that twin turbo is better and give faster spooling time???

Twin turbo is something poeple belived at 80s and 90s was a best before they find out that Truck pulssplitt system and singel turbo is much better

Roman...

You need to be a consultant to the auto manufacturers who are stuck in a time warp..

BMW got it wrong with the 335I TT introduced in 2007...
And how foolish was AMG with the SL65 TT...

And then there is APS with the TT installs on LS1 and LS2 small blocks..

Technically a single turbo is more efficient. several things are in it's advantage: less surface area for heat to escape before it enters the turbine, better flow/inertia ratio, less total system weight, higher compression efficiency possible, higher air pressure/flow rates for the backpressure it creates, the entire system can be made shorter and lose less pressure over the whole system.

But there is one big disadvantage: the single big turbo only has all these advantages over a very small operating range.

Where as a multi-turbo system misses a percent or two in overall system efficiency it more than makes up for that by achieving close to peak efficiency over a wider operational range. This is the key to why multi-turbo systems can achieve better drivablity in real world applications.

To state with no doubt that one is better then the other lacks true knowledge of application.

Maybe they wanted to build a more reliable and durable vehicles instead of hand grenades ?

I admire what you have achieved, but to achieve more your mind must always remain open to ideas and concepts other then what you subscribe to !

Ed A.

PUMPISH · #6 11-25-2008, 02:53 PM

Quote:

Originally Posted by RBYCC

Roman...

You need to be a consultant to the auto manufacturers who are stuck in a time warp..

BMW got it wrong with the 335I TT introduced in 2007...
And how foolish was AMG with the SL65 TT...

And then there is APS with the TT installs on LS1 and LS2 small blocks..

Technically a single turbo is more efficient. several things are in it's advantage: less surface area for heat to escape before it enters the turbine, better flow/inertia ratio, less total system weight, higher compression efficiency possible, higher air pressure/flow rates for the backpressure it creates, the entire system can be made shorter and lose less pressure over the whole system.

But there is one big disadvantage: the single big turbo only has all these advantages over a very small operating range.

Where as a multi-turbo system misses a percent or two in overall system efficiency it more than makes up for that by achieving close to peak efficiency over a wider operational range. This is the key to why multi-turbo systems can achieve better drivablity in real world applications.

To state with no doubt that one is better then the other lacks true knowledge of application.

Maybe they wanted to build a more reliable and durable vehicles instead of hand grenades ?

I admire what you have achieved, but to achieve more your mind must always remain open to ideas and concepts other then what you subscribe to !

Ed A.

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.

AustinsCE · #7 11-25-2008, 05:08 PM

The BMW is an I6. And the SL65 is a v12. Just to clear that up.

But I don't know that I'd bring Supras into the fold. Toyota went from a single early on (MKIII), to twin as a result of technological advancement. Not the other way.

PUMPISH · #8 11-25-2008, 06:08 PM

Quote:

Originally Posted by AustinsCE

The BMW is an I6. And the SL65 is a v12. Just to clear that up.

But I don't know that I'd bring Supras into the fold. Toyota went from a single early on (MKIII), to twin as a result of technological advancement. Not the other way.

I know that sl65 is V12. I did not read carefully and asumed that he talk about v8 like he used to do and its seems like he has most expiriense of this.

I dont realy care what others run twin and why other models did twin on 80s and 90s and why supra went to twin. I know that today people in europe prefer pulssplitt single. And it realy make difference.
I talk from my own expiriense and give the guy advise becaurse I allready expirimented by myself with different turbo setup and it was BIG different to use single twin entry urbo instead twin turbo.
Then it is up to him what he want to use.

RBYCC · #9 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...

Joreto · #10 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 · #11 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.

PUMPISH · #12 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