3L 16valve turbo - list of ready-made parts?

[Tom]

Well speaking from my experience of owning both larger sized 8v (3.1ltr) and 16v (3.2ltr) race motors and also being a highly impressed passenger in Thom's 3lt 16v street car, I would say that there may be some truth to the concept of the 8v developing tq earlier in the rpms however with modern ECUs, fuel and spark control that disparity is pretty easily overcome these days. I also have dyno charts showing a very healthy tq curve in my 16v motor. There's no doubt that making a 3lt 8v street motor is potentially much more affordable though. As always, it often comes down to desired use of the car (and where it will be driven most often) and budget. The added caveat is how much someone is going to charge you to build/tune it vs how much of the work you can do yourself. Plenty of clever people in this forum have put their own engines together and can advise you accordingly (if the info is not already in here and elsewhere). Oh, and Thom can also speak about the differences based on his previous big bore 8v motor so I'd tap into these people for very relevant information.

Thom's previous 8v motor was very similar to mine, which is a pretty good representation of 8v turbo 3 liter motors. I love the power delivery of my motor -- it's a torque monster for sure. However, if not for some pesky local regulations I would have done the same as Thom and built a 16v motor. I'd be surprised if you couldn't work the parts and tune to create more torque everywhere, or nearly so. Perhaps Thom has dyno charts to make that point...

[Thom]

Pretty sure the extra flow of the 16V head could be exploited better down low with a tiny turbo, but if that means trying to replicate the flat-ish torque delivery of an 8V that basically comes out of its efficiency area above 6000 rpm then that's missing the mark, at the risk of sounding like a broken record. I don't miss the power delivery of my former 8V motor at all. That it was still a compromised design and still not what I was hoping for and ultimately frustrating after so much testing was enough to justify building a 16V without really knowing what to expect. If anything I'd say the drawbacks of the 16v compared with the 8v are exaggerated and not really relevant in the real world. There may also be cultural factor like torque delivery probably always prevail among American enthusiasts.

In my experience the only type of engine that will provide both low down torque and power up top without feeling like a totally computerised, sanitised, electric-like motor would be a naturally-aspirated V12. Not sure how to make one fit in a 944 though.

If we call the Dynamic Threshold (DT) the subjective point above which a car comes alive in the sense that the power delivery balances the handing, the road and a driver's abilities then I think a 16v engine will make the DT far more accessible to any driver than an 8v regardless how much resource we pour into it... and in the end it will still be severely outflown by your run-off-the-mill 968 head using stock cams. Lol.

The most bonkers 3L 8V engine I drove was in ETG's development car. An absolute torque monster with a flat and brutal delivery in every gear, perhaps the ideal engine for the average American dyno freak. It still had that typical 8V slightly lifeless character at low loads and when you'd reach 6000 rpm you'd wonder why you didn't see the parachute opening in the rear mirror, such abrupt was the instant loss of power. A very compromised design that I doubt could be bettered in terms of area under the torque curve (last I heard it made 600 hp) but not anywhere as satisfying to me as an overall drive as my 16v with a lot more colours or character to show depending on the occasion.

Sorry, this sounds like the thread is being derailed again.

[333pg333]

I wonder if there's not a synergy between the 3lt 8v / 5-speed and the 3lt 16v 6-speed transmissions?

[Bergerac]

I wonder if there's not a synergy between the 3lt 8v / 5-speed and the 3lt 16v 6-speed transmissions?

Yes this is definately what makes the difference, shorter final drive gets the revs higher into the 16V sweet spot on the street and closer gear ratios keeps on song. Drivability is not just about a number pulled from a dyno in 4th gear. My car would drive like a pig with the standard turbo box and this is why I refuse to use a O1E out of a diesel even though on paper its the strongest box.

[Thom]

Well, I would always consider a taller gearing better to help a turbo load earlier. Then there is the static compression ratio. Then there are the cams. Then there are the roads the car gets driven on. Then there is throttle response and how sharply the revs fall when the fuel cut kicks in. This all affects driving dynamics (and the DT loosely defined earlier). A very YMMV consideration for sure.

[944m3]

I’ve been thinking of trying a smaller turbo for almost instant torque for daily driving. It seems newer turbos can spool much quicker but still retain top end. Considering that this is my daily that I track maybe once a year, I might actually like a tiny turbo. I really like my Raptor but HPT and Xona have piqued my interest.

[Johns944Turbo]

If you're willing to go with a 951 8v head, Lindsey will modify it for you. Then you can choose from many 951 header, exhaust, crossover, intake, MAF, and turbo options. That's what I did. I hope to have it running soon.

[333pg333]

From my knowledge LR don't do any 'in house' head, cam, crank work. They would farm it out. Probably better going to the source and dealing directly....for a few reasons.

[Tom]

If you're willing to go with a 951 8v head, Lindsey will modify it for you. Then you can choose from many 951 header, exhaust, crossover, intake, MAF, and turbo options. That's what I did. I hope to have it running soon.

If using a 3 liter (104mm bore) bottom end, the ideal 8v head is from the one-year only 1989 2.7 Liter motor. The head fits the block as designed. The 951 head has the ceramic liners that can fail, and more importantly the coolant passage does not mate up to the 3 liter blocks. Lindsay and others have gotten 'creative' with the head by welding up a compatible water passage port and then re-decking the head, but I always worry about the longevity of welding on such a significant chunk to older cast aluminum.