Markus951

Well my car is still pretty clean.. but it is far from original.. When I bought it it already had custom pain, sideskirts etc. So I was thinking that I will go with the route of modifing it instead of keeping it stock - it wasn't in that good showroom collector condition, many stock parts where already been replaced etc... It would of took alot of time to bring it back to original condition.

So You think GT30R can push that 3.0 liter engine into 500 hp-s easily? When it was installed to my 2.5 liter 8 valve it spooled up to max boost by 3300 rpm.. and I made 402 hp / 550nm.. in somewhat 5900 rpm.. I had really push that turbo to make power on full stock eninge.. and It surged WOT 5th gear.. I got the surge eliminated when Webcam Race cam was installed.. but then...i broke the enine. turbo was installed into stock location. 3" downpipe etc.. I think I did not make any decent power because non-efficient head cam.

I have seen the same GT30R pushing audi 1.8T 20 valve engine 552hp @ crank..

I am 100% sure that I will install turbo into the right side of engine..with really short intercooler piping and 3.5" downpipe etc..so I quess I as far as compromising the broad powerpand vs top hp I have some benefits instead of the quis mounting turbos into stock location.. i have even considered maybe to keep one turbocharger for daily driving and one for competition use...

GT30R (55in/55out) with 0.82 AR.. would put me into 500hp with high boost.. I doubt it will make any good power with 1.2 -1.3 bar as the compressor midrange starts from that. If it spooled up to max boost by 3300 rpm in 2.5 liter engine.. I am expecting full boost at least by 2800 ropm in 3.0 eninge.. maybe I am too optimistic. Also Id like to keep things safe and boost down for reliability, I dont know can it be done with GT30R what likes high boost...

Also what worries me is the backpressure. I don't know any 3.0 liter 16 valve engines with that turbo.. except Raj I quess..

GT35R with 0,82 AR would put me into 500 hp easily.. I am planning to keep the compress ratio in 8,6:1 range and with variocam it should be pretty sharp and torky in the low end.. I think i would make good power with less boost.. lets say i would reach 500 hp with 1.3-1.4 bar.. But I cannot predict the spoolup. Is there any running similar turbo. With that turbo I would have some reserve for power- but I doubt stock sleeves can handle it without breaking down..

ITS - there are basically 2 options IMO for my application
F2601 will flow 60lbs/min-
http://www.innovativeturbo.com/pages....asp?sku=F2601
or
GT Series Turbo 61mm
http://www.innovativeturbo.com/pages...s.asp?sku=GT61

Both are good for power I am after.. I just havent checked out withc route to go for..

So my questions are..

What is the max power stock (non-sleeved engine can take)?

Do I have to replace valves on the head? - I have done it in my previous motor with SS valves - same ones Ive seen in 20 valve audi race engine taking 800 hp all day long..

What stock 968 head can flow - and how much room there is for improvement? Some say massive 440 cfm can be done after porting..

What kind of tube diameter has to be used when building exhaust manifold? - I will make if from steel instead of SS and have it ceramic coated in and out...

Have any of you used similar turbos on your projects.. and what are the results - i know not too many 3.0 liter 16 valve projects around but still..

Markus

Porschefile

Markus, what you spoke of about "stock" components is a big factor in what turbo you'll need. I know I'm probably going to get flamed for this but, I've noticed that a large amount of people in this 951 group tend to stick more with stock components, even at higher hp levels. That's fine if you are on a budget, though it is far from optimal for higher hp usage. I think too many people are getting confused on some turbo's power capabilities while these stock, restrictive components are in place. At the point that you are making 400+whp, a large amount of these components are just not adequate, and that is nowhere near the most optimal way to go about modifying a motor. True, people have done it, though at what expense of lag due to the necessity to use a larger turbo to compensate for other inefficient components, and at what expense to the top-end power curve? If you are going to keep the stock intake manifold, stock throttle body, stock intercooler, etc etc than you are going to need a larger turbo and you'd probably be better off going with a gt35r. With a properly optimized 2.5l, a gt30r w/ .82 would be more than sufficient to make ~420-440whp ~1.3-1.5bar. Hell, there are people doing it with smaller displacement, albeit more efficient, i4 motors. This is assuming you are talking flywheel hp and not wheel hp, which is what I understood from your posts. The Gt3076r w/ a .82 or larger hotside can support a good ~500-530whp with the proper engine modifications, however I doubt if many 951 guys would like to run those kind of boost levels (30+psi), and at that point a gt35r might be a better option if you want to keep the boost down. At the kind of power level you are looking for, there is a significant amount of power to be gained or lost when it comes to components like intake/exhaust manifolds, throttle body size, intake/intercooler piping diameter, etc. Not to mention, the stock cam will hinder power quite a bit. Unfortunately too many around here ignore these things or just don't think them important enough. They are, and I'll keep saying it until people figure it out.

440cfm? I remember reading that article. That's an unsubstantiated claim. I wouldn't believe numbers like that without seeing a flowchart. From my experience with 4cylinders, those numbers sound completely, utterly and ridiculously way too high. 300cfm at ~.500 to .600 lift @ 28" h20 is a hell of alot of flow. I've heard from multiple sources that the 944/968 16v heads flow around 300-340cfm on the intake side. Of course it's all speculation until we see proof, however I've heard it from enough credible sources that it sounds like a believable ballpark number. If true, It appears like the 16v heads have a huge performance potential that has thus far been relatively untapped.

If you do replace the valves, SS ones will work perfectly fine. I've seen quite a few high hp 951's on stock valves though, so it appears they can withstand the increased power levels just fine, at least for most uses. I wouldn't get any ideas about using titanium, inconnel, or some other exotic alloy valves. The cost/benefit ratio is really low and pretty much non-existant for a street motor. The only effect will be a significantly lighter wallet, and with alloys like Ti, other issues can arise such as increased valve guide or seat wear if proper coatings aren't used. Anyways, don't waste the money with the exotic stuff. Stock or SS will work just fine. If it were a race motor, that could be another issue entirely.

I'd tend to think the stock sleeves should start to become an issue somewhere around the 500-600+whp level. Too few have pushed our motors that high, so there isn't enough evidence or real world results (at least that I know of) to put a definite number on it. For 500fwhp, I wouldn't worry too much unless your block has some issues that may have caused problems with the stock cylinder sleeves.

RajDatta

Markus, my car is an 8 valve turbo. That is the one I run a GT3076R on. The 16 valve conversion I helped a friend with uses my old K27/11 from my previous engine and setup.
When I bought the original 968 turbo RS engine from Chris Cervelli, I also bought the turbo setup with it. Chris had just built this GT3076R for the engine and had not run it at the time. He eventually decided to get out of 951's so I was lucky enough to buy the entire package from him.
I have been very happy with the GT3076R and I can only see it spooling up faster on a 16 valve head.
BTW, I noticed that the yellow car from the picture does not have variocam connected. I guess its 16 valve but no variocam. I spoke in lengths with Jon Milledge because he did the Motec and its tuning on the yellow car and from what he told me, it made around 500-550 on the engine dyno.
Regards.
Raj

RajDatta

Amen to that. I am swapping mine for a 3" inlet to free some space up. I will post pictures of the 2 compressors next to each other. The new 3" inlet should be here early next week.In the past I had to get a 4" to 2 3/4" custom reducer made just to clear the alternator. I have to have AC in my car so deleting AC was not an option.
Regards.
Raj

Markus951

I am not using stock intake manifold but custom one with velocity stacks and dual plenum.

same goes with intercoole and piping everything will be pretty much custom performance oriented parts..

same goes to exhaust with will have 3.5" dowpipe going to 3" catback..

same goest to my 40mm Tial wastegate witch will be vented to atmosphere.

I am not planning to keep my car stock or build it with custom items. What I wanted to explain earlier why I choosed that route of modifing it even more.. it wasnt anything that I bought 951 with 10 000km and 100% originall.. I love modifing.. and..making custom stuff...make it better IMO... thats what petroheads do

Lets say the compromise between the looks and performance is 60% performance and 40% looks...meaning if I have to cut the body to mount exhaust manifold and turbo.. I will do it...

I know people here who are saing that why do you do that.. why do you change that... its been developed by porsche and its engineered by porsche meaning that now doubt it will work etc.... im not one of them..


As far as the 16 valve head goes....I think it will flow enought in stock to make 500 hp. but yeah... no flowcharts..

RolexNJ

I love what you are doing Markus, good for you getting back in the game. I cant wait to see how this new project of yours turns out! Anyway, as for the advice that Porschefile gave you, I think he has some very valid points, but is also trying to save you money too. He's a good guy, isn't he? Regarding the 16V head? While I don't have empirical or quantifiable data, and this is 100 % pure speculation so I am not giving anyone mis-informtion on Rennlist, I would venture to say that the 16V in stock form will hit that 500 HP mark. It flows a lot more than an 8V, but how much, I don't know? But, we shall see in due time. I know there are people who are flowing S2 and 968 heads. So stay tuned...

Raceboy

I'm getting my mildly modified S2 head (full-radius valve-job, little porting, new valves etc) to the flow-bench this winter, then we can get hard data
It's possible that by that time Markus has gotten his 968 from Japan and we could compare S2 and 968 heads (though mine isn't 100% stock one then).
BTW, I have pretty good odds to buy those seats for my car, but we'll see

Markus951

Hey

I went out today And took some garage photos.. everythign seemed as I left her:
Future 3.0 16 valve body:


New location for turbo.

As you can see i am planning to put it with 45 degree angle. 9" air filter will be mounted behind the front bumper From the turbo i will custom make 4" piping with 90 degree bend what will turn down from the turbo to the filter location. Hopefully that 4" piping can be mounted behind the pop-up light.
You can also notice blue cilicon hose dips. This is how long the distance is from turbo to intercooler



Washer reservoir tank powersteering fluid reservoir have to be relocated. to make room for exhaust manifold..


Couple of more shots from today's conditon





By the way

Can someone give me advice by sizing the turbes for custom exhaust manifold, and also the lenght? I know that smaller the tubes faster the gassflow, but..

I am planning to make it from mild steel instaed of SS. and It will be ceramic coated from in and outsied. Reason for that is strickly that steel is stronger and I am not after bling bling but good preforming item!

This example from one BMW turbo forum.. I am most likely go same route. I am not sure can equal lenght manifold be created because of the lag of room under engine bay, but will see

http://i26.photobucket.com/albums/c1...o/P1300004.jpg

http://i26.photobucket.com/albums/c1...bo/grenrr5.jpg

Markus951

More ideas:

Most likely I am going to use COP (coil in plug) ignition instead of single coilpack or distributor. At the moment I know at least one COP what will work with 16 valve head and that should be the COP what is originally used on Porsche Cayenne Turbo. (Porsche part # 948 602 104 03, Beru # ZSE 012)



Have any of the users here done similar conversion?

I know at least one guy who have installed them into 928 S4 and as far as I know heads are pretty similar with 968 when we are talking about spark plug holes (diameter, depth)

Markus

Olli Snellman

Markus,
i think you can find similar cops much cheaper for example from BMW product line. I suppose some Opels use them as well.

Raceboy

Olli, point is that they are similar but with different secondary coil power outputs. I can get brand new VAG coils off the 1.8T for 30€, but those have their limits in app. 75-80hp per cylinder.

Olli Snellman

OK point taken. I suppose you have that black 951 with Vems installed. I sent last summer one S2 headgasket to Markus, i suppose it went into your car... Can you tell more about Vems installation, if not in public, private is also OK Me and a friend of mine have also consired using Vems system, so all tips are most welcome.

Raceboy

Actually the owner of that black 951 is my friend Kert, but I did the VEMS installation
You can post questions to the thread ( https://rennlist.com/forums/944-turbo-and-turbo-s-forum/281818-vems-genboard-v3-3-installed-on-a-8v-951-3-0-a.html) about that car or PM me.
I can say that installing VEMS on 951 is pretty straight forward as it can utilize stock crank trigger arrangement (rpm+crank home) and all the other sensors.

Chris White

If you want to use some nice 16v valve train parts I have had some made up for projects and I have some parts in stock –
The high temp ‘super alloy’ valves (good to 2200f) go for $880 a set (16)
Stiffer (10%) springs (also lighter) - $340 a set (16)
Ti retainers - $350 a set (16).
Locks - $80 a set (16).

I can do half sets if you just want to do the exhaust sides.

Chris White

nick_968

Markus, my Motec guy did some tests with COP versus Wasted Spark and Coilpack and found that COP does not always improve power and sometimes he found power was less and for the extra cost and work it was not necessary to make good power. For that reason we used a Ford coilpack and ignition amplifier rather than go for the extra expense of a COP setup. I do know that two of the UK guys Rick Cannell and Fen both use the COP on their 951 and are very pleased with it but they came from the standard Distributor system so will of course see a big improvement.

I will be watching your project closely and innovation is always good to see! Good luck.