Konstantin

you increase thebackpressure if you do this.
either other Turbo or bigger engine is the way to go.

Konstantin

Markus951

Konstantin, are you using the same turbo as I am?
What im saing is that all the piping is originally made for KKK unit what has slightly different desing compaire to ballbearing units. It cant be more restrictive than exhaust housing itself (what is slightly smaller compaire to KKK unit). It is a little less in diameter, but not less than exhaust housing would require.

Markus

Konstantin

check firts your backpresusre. If it is ok to low or to high.
I would go with a bigger engine et least 2.8L This will solve youa lot of problems.
I think your turbo is ok
No I do have a another one

Konstantin

Markus951

Stroking as using 3.0 liter S2 knife edged crank, 1st gen 944 con rods (forged), stock 944 turbo pistons?. I actually have had it in mind, but have not found a decent information how to do it. Some say that you need other rod's than stock forged units, some say that different pistons are required. I could find s2 crank and forged con rods quickly, but is that the way to go for..
How strong is the stock bottom end anyway in 2.5 liter configuration? How many Hp/Tq it can handle. Some say its good at least for 450rwhp, some say even more...


markus

NZ951

Markus, there is a HUGE amount of info in history here is bore and stroking...

Markus951

Ok!

I if I will do it then, by using S2 crank, 944 forged rods from early model. 951 pistons, would it be reliable that way? Comments?

fast951

MArkus951, I appreciate your excitement about a new project, but take a minute first.
Before making a list of what parts are needed, you need to spec out the engine then collect parts.. For a 2.8l stroker, you need 3L crank (S2 or 968), 951 rods (aftermarket forged if you have the $), custom pistons with a "pin height" designed to work with the 2.8L long stroke..
If you use 3L crank, 951 rods, 951 pistons.. The piston will stick out of the block.

Some people cut corners and use shorter rods.. It works, but not a good approach.. You'll endup with a less than ideal crank to rod ratio.

Another way to get a 2.8l is to use a sleeved block (106mm), stock 2.5l crank, 2.5l rods and custom pistons.. This is what you call a big-bore..
You can go to a 2.7l (big bore as well) and have some MID sleeves.

For 944 sleeved blocks contact Chris White, he is very experienced with the 951 sleeving process. As well as the 2.8l stroker.

Markus951

Thanks for advice, I thought that it cant be so simple, otherwise there will be a lot more 2.8 liter drivers around. It keep those advices in mind when Im going to do something with bottom end. I have not actually driven so much with my current setup, so i think there is plenty of room to go on getting it into boost, improving the torque cruve etc. One reason for slow spoolup on 951 is the exhaust system (specially the crossover pipe)is there anyone who has placed the turbo on the other side of the car like here?

Shorter exhaust plenums would help a lot here right?
Or have any of you thought about replacin the crossover pipe with smaller diameter unit, it is not wise when using KKK turbos, but BB units are different, maybe there is a room for me to improve the general behavior of the car.
Im not the specialist, just a thoughts here.

Markus951

Went to the dyno yesterday.Got 402 hp/550nm of torque @5000 rpm.

Stock head
Stock valves
NA cam with 2mm more lift in exhaust/4 degrees more duration.
GT30R turbo
3" exhaust with downpipe
Stock intake manny
Stock intercooler
Stock 2.5 bottom end
1.8 bar of boost.
Will post you the dynograph when i got it scanned.


PS! our dynos here are a bit different then dynos in U.S (like mustang/dynoyet). Our crank HP is what you have on rear wheels. I have also driven my car on 1/4 mile, when it did not have NA cam and ignition and fuel map was far from perfect. I was running BIG RICH on that day, with really bad rear tyres, but I still managed to clock 12.76,

According to Edman951 who has same turbo and approx same quater mile time (12.66), has calculated that he's car should be 400+ on RW to get that kind of result.

If I practice a little bit, and will run on wider tyres Im more than sure that my car is capable of 12.2, even flat 12, becase I was basically first time in my life in quater mile, so there is room to go.

Markus

NZ951

What kind of dyno were you on? Rolling Road or Hub? Know the name of it? I dont get what you mean by US WHP is your Crank.

26 psi is a lot of boost!

Markus951

IT Was BOSCH FLA206 4WD rolling road dynamometer.
http://www.rollingroad.de/dyno_htm_e...03_206_20e.htm

What I mean by comparing the dyno numers is that our HP seems to be a bit stronger than HP on mustang or dynojet. 1/4 mile is also a good to check, and then compaire. 12.76 quater mile must be a proof that on mustang or dynoyet my car would do 400 rwp instead of 330 rwp. Also my 680cc are on 100% duty cycle @ 6500 rpm, and im running 1.8 bar of boost thats 26.1 PSI. that should give us some idea also. Is there anyone with 330 on rear wheel and 12.76 quater mile time?

I really dont care that much of the dyno numbers as far as car performs good. my avarage fuel consumpion on highway is 10 liter per 100km, even if you go 120-130 all the way. It looses grip every time im doing full loads on 3rd gear. It goes from 100-200 with 4th gear approx 10.5 sec. It does 12.76 on quater mile, thats what is important in my opinion

My top end from 5000 rpm is rich at the moment, and I still have surge on 5th gear on full load. I wll put adjustable cam gear, then play with it, raise the boost to 29 psi and lean it out on the top end I shoud gain some extra 60-70hp and some 50nm of torque.

Konstantin

thats why I say post your accelaration number. This is more importand
Dynos in the USA usually read too HIGH numbers.
That why a RUF Porsche with 520 FWHP has over 500 RWHP in the USA etc etc. It is not thedyno it is the operator who either do not knot how to use it or wants to see high numbers.
yes your car sounds like it has real 400 HP

did you have a dyno with only 1.3 bar? My 2.5L car had about 380 HP at this boost
The Bosch FLA and teh MAHA can really read the engine or flywheel HP with 2-3 HP acurancy.
I am wondering why the US dynos do not do that?
A Gt3 cup car with 380 HP has 380 HP on the rear wheels in the USA. how is this posible?
So do not worry about big hp. stop your 100-200 km/h times and you know the power you have . 10,5 sec is very good, as good as a 993 TT but you must know that thespeedo is not accurate.

Konstantin

Skunk Workz

Tested your setup in the EA Pro,Markus,I had all the specs for the parts you listed... it says 400 hp at the flywheel...congratulations,you are one of very few who have a setup that gives the theoretically possible hp... (in other words,claiming RWHP when it is flywheel..or using tons of ice on their IC's)...but,hey,I guess they are hp magicians.... If you get it leaned out over 5000 rpm you should see close to 420 hp.

Konstantin

@ skunk
what do you need from me to calculate my power?
I would like to see what the software says. I calculatet it already by my self the old way with a lot of maths and calculation and would like to see if it is close.
My engine is a 3 L with heavily modified head big Turbo that flows 60 lbs etc etc

Konstantin

Skunk Workz

I would need quite some specs for it to be accurate... Full flow curves,port diameters,valve sizes,valve spring specs,cam type (or atleast lift,duration and lobe center), what kind of turbo,the turbine A/R or Sq.CM,diameter of exhaust system,etc...

But I can get an approximation using some parts I already have specs for: You have:
a 3-litre block?

Ported 951 head (I would need some flow CFM @12mm unless it's a Lindsey head,and if the valve diameters are changed from stock I need that too)

Stock exhaust manifold? 3 inch exhaust system?

Stock Intake manifold and throttle body?

What type of cam? Stock 951 or 944,or a custom one? Stock hyd. lifters?

What kind of turbo? Plane,single ball- or Dual-ball bearing? Boost pressure?

Stock IC?

Maximum Rpm?

Then I can get quite close... Sorry for hijacking the thread,Markus...