8v or 16v?

[Ez-Bone]

I've heard a mass of rumors that it is 'oh so bad to turbocharge a 16v head' and would be better off with an 8v head.

I've actually gotten into a few very angry arguments with people about this matter and they hate it when I prove them wrong.

I've been told I can't use 16v and turbocharge them because something about the valves not able to take the added pressure and thus, engine go bye-bye. But I have a mindset that, if I want to turbocharge something. I'm going to properly prepare it to take on such forces. But I'm still told I can not do it, that the engine will blow up no matter what.

On the flipside; there are plenty of people out there that have done this and get staggering results from turbocharging a 16v head, even the variocam head (the 968's powerplant). Some getting as much as nearly mid 500s (which... I want to say numbers don't lie but geeze that is A LOT for such little anorexic cars lol). Which brings the other side of things. What powertrain would be able to handle such power? I've been told that even the 951's powertrain and axles aren't up to spar to handle abusive power like that, or the 968s; but if I've been informed wrong, please let me know. I'm actually curious to trail and error this by myself if I have to but outside input and advice would be greatly appreciated too.


So yeah...

8v or 16v?
I want all the information I can possibly cram into my skull about this dilemma, what it takes to build a successful turbocharged 16v and it's pros and cons over an 8v build and vice-versa.


PS: One video I saw on Youtube really caught my interests, the engine was reving VERY fast compared to others I've seen on the dyno, unless the dyno they used was worn out or something.

[Pete R]

I've heard that the factory made a few 3.0l turbo's for racing but didn't produce them because the car would have been faster than the 911 (...and that would be sacriligious).. I assume that was done on the 16v head. Mighnt want to look into that a bit. There's also a company (herr-kunn) that turbos 32v 928's and those work fine. I imagine those would be similar heads too

[rick13]

all it takes is money.

[Ez-Bone]

Originally Posted by Pete R

I've heard that the factory made a few 3.0l turbo's for racing but didn't produce them because the car would have been faster than the 911 (...and that would be sacriligious).. I assume that was done on the 16v head. Mighnt want to look into that a bit. There's also a company (herr-kunn) that turbos 32v 928's and those work fine. I imagine those would be similar heads too

My thoughts exactly, and I think you are referring to the 968CS/Turbo S. My base point on the argument was 'if man made it, it can be altered to work differently and repaired no matter what.'
Also, this is one of the guys that claim they have turbocharged a 16v head and are easily in the 400hp range
YouTube - Revline Racing RR400 (Porsche 944 Turbo S) - 2005
I love how it revs up so quickly

Originally Posted by rick13

all it takes is money.

Ja, but I would at least like to have an idea what I am up against so I am not mindlessly shoving out money, that stuffs hard to come by these days :P lol

[Catamax944]

Ask the 951 guys over on rennlist ,you will get a lot more answers, many have done it. And for your delight Porsche : 968 - eBay (item 110642369820 end time Feb-05-11 14:34:45 PST)

[962porsche]

as for the trans and axels the motor in one of my 944's is putting out over 600 PH and 500 foot lbs tork . i raced it all last year with only one problem i blow apart a CV coming out of the pits . the axel had over 160k miles on it i did two 24 hour races and three 6 hour events along with six 4 hour events every thing is still fine . i only use new porsche OE CV's . and no its not a porsche 944 motor in that car . when i was an engineer at porsche it was chassis and suspension not motors but the reasion they did not use the 16v heads was because of reliability . what was found was that the 16v heads did give just a little better HP up on top . but the 8v heads gave better tork across the hole power range giving up just a little top end flow . getting out of the american mind set of just looking at the HP numbers look at it as both HP and tork along with driveability from them .

[Ez-Bone]

Originally Posted by Catamax944

Ask the 951 guys over on rennlist ,you will get a lot more answers, many have done it. And for your delight Porsche : 968 - eBay (item 110642369820 end time Feb-05-11 14:34:45 PST)

I'll check that out then and on the ebay auction... uh... yeah, I think my pocketbook just threatened me with a knife if I even thought about looking at that auction again

Originally Posted by 962porsche

as for the trans and axels the motor in one of my 944's is putting out over 600 PH and 500 foot lbs tork . i raced it all last year with only one problem i blow apart a CV coming out of the pits . the axel had over 160k miles on it i did two 24 hour races and three 6 hour events along with six 4 hour events every thing is still fine . i only use new porsche OE CV's . and no its not a porsche 944 motor in that car . when i was an engineer at porsche it was chassis and suspension not motors but the reasion they did not use the 16v heads was because of reliability . what was found was that the 16v heads did give just a little better HP up on top . but the 8v heads gave better tork across the hole power range giving up just a little top end flow . getting out of the american mind set of just looking at the HP numbers look at it as both HP and tork along with driveability from them .

Yeah, that was my main concern about power, how and what parts can handle it. I'm fine with just mid 400s though, there is apparently a 944 out there putting out nearly 700 (and I'm not talking about the Audi powered one) and using 968 powertrain parts to get it moving.
And the explanation about its reliability makes more sense now than someone just simply telling me 'no it can't be done' without reason.

And if you want abit of honesty, I, at first, only wanted the Variocam head because, frankly, cosmetically it looked better when the bonnet was open, in my opinion :P but after I dug deeper and learned its flowrate differences over the 8v, that's when this ambition of wanting to test it's limits came to mind

[Pettybird]

16v headed turbo=more moneys. simple as that.

there are a lot of 8v parts or you can make what's out there work a lot more easily than 16v stuff. all three 16v intakes go right where the turbo sits on a 951, for instance. SFR makes a 16v turbo manifold, headers, etc. it's the way to go if you have the pockets.

the 968 turbo S used the 8v head because Porsche pulls the "if it ain't broke" card more than any other automaker, and they were just about bankrupt and couldn't afford the development. back up to 1982, though, and you'll find the 924GTP running around with a turboed 2.5 with a prototype 16v head, though...

[Pettybird]

and get a Turbo S "AOR" transmission. it's the strongest one.

[Ez-Bone]

Originally Posted by Pettybird

16v headed turbo=more moneys. simple as that.

there are a lot of 8v parts or you can make what's out there work a lot more easily than 16v stuff. all three 16v intakes go right where the turbo sits on a 951, for instance. SFR makes a 16v turbo manifold, headers, etc. it's the way to go if you have the pockets.

the 968 turbo S used the 8v head because Porsche pulls the "if it ain't broke" card more than any other automaker, and they were just about bankrupt and couldn't afford the development. back up to 1982, though, and you'll find the 924GTP running around with a turboed 2.5 with a prototype 16v head, though...

Right, I've heard of SFR, I believe they are the ones who wrote the article about the guy's 951 S and dubbed it Red Dragon. It was proclaimed to have a 16v setup putting out lower 500s, But as for manifolds and headers, I can't fathom that they would that much, ja? I mean, Lindsey has some fairly pricey parts themselves but compared to what I've seen for other junk *coughFerraricough* theirs is very well priced.
And I remember that bankrupt story D: that was when I found out about their halted plans for a 911 saloon (dubbed the 989 I think) was basically a 993 in the front and 996 look-alike in the rear. But that's getting off topic :P

As for this transmission you mentioned. It sounds rare... do I even have a running chance at getting one? :P

[Pettybird]

they come up enough...one was on here or Rennlist last week. moly coated shafts, hardened 1st and second, and it has the strongest LSD of any factory transmission. figure $1400-2000 for a good one.

9ff has the wildest 16v car--twin turbos on the right side.

[Ez-Bone]

Originally Posted by Pettybird

they come up enough...one was on here or Rennlist last week. moly coated shafts, hardened 1st and second, and it has the strongest LSD of any factory transmission. figure $1400-2000 for a good one.

9ff has the wildest 16v car--twin turbos on the right side.

Oh so technically the only thing changed in the hardened transmissions are the first few gears?

and if you are referring to the GT9, 9ff then yes, that thing is wicked!

[Pettybird]

how about this? cleaner than a turbo install...

foto's - 944 racer Rotrex

[HondaDustR]

Somebody here had a 16v with an eaton on it, IIRC. Don't know if it's still running. If I had the money, I'd build what 9ff has, otherwise a SC 16v would be really fun.

The youtube vid up above looks like a standard turbo S, which used the 8v turbo head. The intake manifold gives it away, and in the other vids, it's definitely 8v.

[Endat]

They have used several different engines in that same Revline car from the youtube video... One of their videos says it has a newly built 16v turbo engine (replacing the 8v turbo), but in the videos, they never show the engine.. and the track videos, it revs a lot like a 8v turbo. edit: they added a 16v turbo video about 4 months ago YouTube - 944 Turbo, 3.0l 16v @ 0.6 bar, in-car 46 seconds of joy @ 0.6 bar flying past a 911 Carrera.

I've never ridden in a 16v turbo 944/68, or even seen one in a real action scenario, but I bet it would scream, comparative to how a 16v n/a pulls away from a 8v n/a

8v : RREEEEEEVVvvvvvvvv... shift
16v:rreeevvVVVVVVVVVVVVVVVVVVYYYY.. shift

Ive hunted down and asked some people about this conversion so that all of my noobish questions arent permanently posted online. Basically it all comes down to $$$... The easy part is building the engine itsself.. start off with rods/pistons, then making the turbo manifolds fit (intake/exhaust), you could just get normal 944 Turbo intake/exhaust manifolds and chop the flanges off.. then get some new ones machined and weld them onto the manifolds so they'll mate with the head (or you can try mating the turbo manifolds to the 16v ones you rip off your car). One person I asked thought it would be a neat idea to start off with aftermarket stainless steel turbo headers.. kinda pricey though. The real killer in this conversion is tuning.. The consensus says that you'll spend ~$4k rebuilding the 16v engine/head, ~$3.6k on a motec standalone engine computer, and then another ~$2-3k making the wiring harness and installing it and ~$5k just sitting on the dyno. (parts+labor, unwanted parts, labor, labor+dyno usage) That's a lot of labor...

I think this job can be done a lot less expensively, especially if you get some manifolds made cheaply (its possible for less than $200) and if someone comes up with an EPROM chip thats tuned for a turbo, that would get rid of the standalone ecu problem. I mean, I know that not all turbos are built the same and one chip made for one turbocharged car isnt gonna be the same for another build and all that bs, but if someone just stuck with a K26/7 and all other standard turbo parts (intercooler, bov, etc), it *could* give others a good place to start from.

Basically, the "just a buy a turbo" people think its too complicated and by the time you get it running you'll have spent more than the turbo would've cost without having done the brakes, suspension, etc. Besides, the 8v gets out of the corners better and if you want more real power, you could just bore it or use a 3L block. While on the other end of the scale the "its got a lot of potential and i dont care what its worth afterwards" people think its a neat idea, and wonder why Porsche didnt do it in the first place (same reason i suspect why there isnt a Cayman Turbo). I mean, why would you make a car that doesnt reach its potential? Conservative figures suggest that the 2.5L 16v would make about 325hp at about 0.8 bar if Porsche or anyone else had made a decent effort to produce it, obviously this engine in that form is a threat to Porsche's future models.. as seen in this youtube video YouTube - 968T Chasing Carrera GT (~:30 - ~:50) where a turbocharged 968 chases down and passes a Carrera GT that leaves the camera car for dead on the straights (dunno, but i suspect it was 16v).. Then on the FARRR end of the scale, you've got the "**** it, just cram a corvette v8 in that beast... 400hp WOOOOSH" people, who I think are better off for keeping it simple.. but the Porsche purist in me always thinks the same thing when the hood is open... "thats not a Porsche engine, FRANKENSTEIN!!!".. as if it really matters.

Just my 2c.. I probably still know just as little as when I first had this crazy turbocharging dream. But I have 2 engines now after a bad deal, so maybe i'll turn the paperweight into a firebreathing turbocharged monster (after i get the cylinders fixed)

PS: I talked to someone who worked for a shop that did a turbo conversion to an S2, he said the tensioner was a tuning hassle and a failing point of an application like this and the client opted to remove it altogether (i wonder how, smaller chain? functionless tensioner-shaped piece?). But he also said that if you had a conservative amount of power (upper 300's, lower 400's) and drove it nicely, it would probably be just fine.

Oh yeah, on the powertrain, I would personally go for the 968 6-speed with an LSD and well-suited gear oil.


Endat

[James Chimney]

Here is what I found on the Turbo 968 motor so Porsche did it but didn't push it on the market...wish they had Porsche 968 - Wikipedia, the free encyclopedia "Porsche briefly produced a turbocharged 968 sold as "Turbo S", a fairly odd naming choice for Porsche which usually reserves the added "S" moniker for models that have been tuned for more power over a "lesser" counterpart, such as with the 911 Turbo which has infrequently been available in both "Turbo" and higher-performance "Turbo S" guise. Only 16 were produced in total and only for sale in mainland Europe. Tests conducted in 1993 produced a 0 to 60 miles-per-hour time of 4.7 seconds and a top speed of approximately 180 miles-per-hour, performance comparable to the much newer Type 996 911"
so the engine and drive train can take it....would be my dream engine set up in my 85.5 na 944

[Endat]

Originally Posted by Pettybird

9ff has the wildest 16v car--twin turbos on the right side.

This one?


I like it, but i would like it better if you were able to close the hood without cutting a hole in it... the piping looks like a royal mess too, but it posts some pretty steady torque throughout the entire powerband, peak comes at I think ~1500rpm?

[333pg333]

No disrespect but there isn't a lot of good info going on in here re this question. You would be better off if you're serious to check out the many different threads on Rennlist. Using the Green Hunter pictured in the Revvline videos is a good place to start. Look up Duke's threads and you'll find quite a bit of valuable info in there.
His current 3L 16v 968 motor has over 500 'true' whp on Swedish pump gas at 17 psi and plenty of early torque.

The 16v head is way better than the 8v in both flow and resistance to knock. More work is required to do this properly but if it's merely a question of which one is better then there is no question at all.

Having said that you can make an 8v perform very well indeed. Anyone who has driven a 951 with even 400 true wheel hp will know that this is a very quick car. Having a lot more than that will make 90% of people slower...or worse...

I hope to have this 3.1 8v dry sumped motor on the dyno next week sometime. This will produce over 500hp and torque. I am sure about that. There's very little that hasn't either been totally modified or just custom made on this motor. Can't wait!!

[romad]

"getting out of the american mind set of just looking at the HP numbers look at it as both HP and tork along with driveability from them ."

Like just looking at HP does not mean we are not making improvements in TORQUE? The work done to make the car fast is HP If I improve HP over a select RPM of course I'm making improvements in TORQUE.

As for the American mind set, in regards to the reciporcating powerplants, the rest of the world does not even come close to what the average "hillbilly" is doing in his garage on any given night.

[ernie9944]

Originally Posted by romad

As for the American mind set, in regards to the reciporcating powerplants, the rest of the world does not even come close to what the average "hillbilly" is doing in his garage on any given night.

LOL agree 100% ,but there also some Porsche owners out there that can extract tremendous power out of their old good 928- V8 -16V .Plus he has the dino chart to prove it ,your talking about serious HP & torque here.