Decision to make - "4" or "6" Options

[sww914]

Cute, I wonder which one is more reliable at 400 hp. (IMG:style_emoticons/default/biggrin.gif)

That one saw 27 hours in the lab under boost the whole time and didn't even have more tha 2% leak down hot... The highest oil temp it was was 217 and the highest head temp was 320 which is about 30 degrees cooler than a stock 2.0 makeing 1/3 the power..

It has dry sump oiling, billet rods, billet cam, Nickies cylinders, CNC heads and basically all the typical failure points for the TIV removed..

The main fault that the TIV has had that leads to failure has been misconfiguration and corners being cut in design and application. We haven't had a catastrophic engine failure in almost 4 years on the street, on the track or in the lab.. It might happen tomorrow, but it's been 60 engines since it happened last.

Wow! that's about 1500 miles at 60 MPH! No 6 Cyl could last 1500 miles.

[Jake Raby]

Wow! that's about 1500 miles at 60 MPH! No 6 Cyl could last 1500 miles.

Hell, according to the common thoughts displayed by most members here the /4 couldn't last 5 minutes at 300+HP.... No way it could last 27 hours under boost!

My point was that after that amount of time under boost none of the symptoms of a failure or wear existed.

[effutuo101]

There are + and - to both sides. Figure out the cost and the maintenance and what you can afford and go with that. Which ever way you go, you will have fun.
Do the brakes and suspension to what you want first. It is great to go fast, but you have to turn and stop.

[DNHunt]

I've been there when Jake has a motor on the dyno. He Flogs the sh*t out of em. No way I could emulate it on the road. I can guarantee you, you would wear out first unless you were in incredible shape. He's on em all the time, finishes a pull and then, blips the throttle about 3 times to bring down the head temps and then he's all over it again.

There are breaks to change things like jets or stuff, but when it's running it is abused.

I would say that would be more like 700 miles of hot lapped 1/4 miles. 20 passes at a time with 1/2 an hour or less in between.

Mine saw pulls to 7500 rpms, blips the throttle and then it started over with loads at 3500 and on up again. I tell you I was proud my engine held together for a day on Jake's dyno.

[iamchappy]

Jake thats amazing, and i do appreciate what your doing, please keep taking it to the limit. But there are limitations to the type 4 and you and i well know that your not gone to be able to build one that will match a big turbo six engine. 930 engines can support over 700hp you show me a type 4 thats not built like a grenade with the pin pulled that can do that.

My engine at around 420 hp will be a dependable daily driver and should hold up for many years and as many miles as a stock type 4.

[Twise]

Six - Six - Six

[Jake Raby]

(IMG:http://rdtlabs.com/Pictures/4camcarrera/4%20cam%20Carrera%20pics%20028.jpg)

700HP is possible with these on a 2.8L engine and moderate boost.... It should be running by this time next year IF things continue to go well.

You forget that the TIV has the same metallurgy as the 911 aluminum crankcases and that it has a shorter crankshaft.

With the same parts that are used in the six making 700HP the same longevity should be a capability with a roller cammed, billet headed, Nickies equipped TIV.

Of course at this level it's not a Type 4 engine any longer- it's just plain MassIVe.

I do know of a 2366cc TIV from Europe that has been drag racing for 7 years making over 500HP and it survives..

So what do you feel is so weak about the engine that makes it unable to support the power it can generate?

Longevity is something we have never had a problem with, the only time things break is when the wrong jackass with a wrench in his hand become a catalyst. That jackass is the biggest enemy that the TIV has.

[PeeGreen 914]

(IMG:style_emoticons/default/drooley.gif) ooooooo...car porn.

[iamchappy]

It's time you sponsor a 24 Lemans car. WOW!, If you can get a 2.8- 4 to crank out 700 hp with mild boost and run full boost all day long, you have my vote for the Nobel.

[911quest]

I helped build and prep a 2.0 type 4 that was racing at Rennsport III it is cool car but we are at the point to be more competive we need more grunt do you spend 5-8000.00 on a type 4 or do you go with 2.0-2.5 Six it's a no brainer.

[Jake Raby]

You could keep the prize.. If i could do that I'd be plenty satisfied with the ability to make the six following frown at the accomplishment ;-)

Hell, maybe we should start playing with sixes.

[PeeGreen 914]

You could keep the prize.. If i could do that I'd be plenty satisfied with the ability to make the six following frown at the accomplishment ;-)

Hell, maybe we should start playing with sixes.

Yes please (IMG:style_emoticons/default/biggrin.gif) .

[degreeoff]

So what do you feel is so weak about the engine that makes it unable to support the power it can generate?

OK so here is my question.....You say these type IV motors are as strong as the sixes Jake. What about (my idea of a failure point) the fact that there are only 3 main bearings in the 4 as opposed to the 7 in the six? I would think this to be the main failure point or area of 'twist' which leads to other 'misalignments' (IMG:style_emoticons/default/confused24.gif)

[ConeDodger]

I have about 700 miles on my newly built Raby Kit 2270. The motor actually exhibits better numbers as far as temps and such so I can honestly say it isn't working as hard to make 170+ HP as the stock motor was to make 90 HP. It has amazing torque. I can be on the freeway in 5th gear at 70 and just accelerate without downshifting to pass. When you go through the gears it pulls like a raped ape. I am so pleased with this motor that I have my eye on his turbo project. Of course that would be a Jake built motor as I don't think he will make kits for it.
I have no concerns about longevity at all. As I said, it seems to be less stressed than the stock 2.0 liter.
I would actually have to disagree with those who think the 6 is an obvious choice. The application of modern testing and technology makes that choice less obvious every day. It is a good choice, certainly but not the only one.

[Jake Raby]

OK so here is my question.....You say these type IV motors are as strong as the sixes Jake. What about (my idea of a failure point) the fact that there are only 3 main bearings in the 4 as opposed to the 7 in the six? I would think this to be the main failure point or area of 'twist' which leads to other 'misalignments'

I counter this with;

The reason the six needs more mains is because it is LONGER to support two extra cylinders, the longer span creates MORE flex over the span of the crank. This means that more support is needed to keep flex down.

We keep flex down by using stiffer cranks and also by using the largest rod bearing journals possible, this reduces "overlap" between the crank throws and makes for a stronger crank as well. This is why my rod journal of choice is .100 larger in diameter than the stock 2.0 journal size.

With our 4340 chromoly billet cranks flex is also greatly reduced, but not even the stock German cranks had flex issues, we turn these to 9,000 RPM with up to FOUR POUNDS removed from them, one of these has four seasons of peoduction racing under it's belt and still passes magnaflux every time.
Here is a picture of that particular crank


Here are the rod bearings out of that engine after 12 45 minute races, one season of use @ near 180HP from 1832cc


And here are the main bearings


I don't see any signs of wear, do you???? Want a few hundred more examples of reality? I have them because I keep logs on EVERYTHING, nothing like data and proof.

BTW- The TIV actually has 4 main bearings.

The 547 4 Cam Carrera engine also used "only 3" main bearings as illustrated in this pic I took while working on one last month(This is actually a 592 from a 904). The 547 engine could sustain 8,000 RPM at Le Man for 24 hours without failure and that was with metallurgy from 1955.
(IMG:http://rdtlabs.com/Pictures/4camcarrera/4%20cam%20Carrera%20pics%20305.jpg)

That being said I have seen TWO broken TIV cranks in my life, both came from 5,000 pound VW buses after being driven across mountains... I have never personally experienced one of these failures and lord knows I have broken at least one of everything else over the years.

The key is proper dynamic balance and combustuion balance, all 4 cylinders firing evenly with little variance in CR and mixture quality is key to eliminating failures.

This post has been edited by Jake Raby: Nov 28 2007, 06:19 PM

[Chuck]

My .02 and it is worth precisely that . . . .

I REALLY struggled with this as I had to make the decision what to put into my '73 restoration project. I bought the car with the intent of doing a turbo Subie swap. I then decided to keep the car stock. That decision led me to look at Jake's offerings. With the 4, especially one of Jake's 4s, you've got a very nimble, reliable package. With the 6, especially a larger 6 (3.0 plus), you gain some weight, you gain some complexity, you gain some additional maintenance expenses due to the price of Porsche parts and you gain horsepower and torque. I found a really nice 3.2 6 and that will be going into my car. With the MSDS headers and a Steve Wong chip, I should be making ~250hp in my teener with the stock injection.

My 1.7 TIV will be crated and stored. When the 914 is complete and my bank account recovers, I will begin a 550 Spyder kit (another wanted car). When the time comes, I will call Jake again, order one of his engine kits, rebuild my 1.7, and put a lightweight, reliable, fire-breathing TIV making ~200 or so hp into my lightweight, tube-framed Spyder.

[Racer]

(IMG:style_emoticons/default/icon_bump.gif)

I've decided to go with a 2.0L 4!

Picking it up this weekend (IMG:style_emoticons/default/smile.gif)

[Gint]

Excellent choice.

I've had, what... 7 914's over the years. I have had both and currently own a 74 2056/4 and my /6 is still in resto state with a proposed 2.7.

With that experience, I think what I would really like to have is a very nice 914 with a Raby 2270. I'll have to drive Rob's one day if I ever get the chance.

[Jake Raby]

Great choice..
I am working on the finalities of the 2008-2009 engine kit program as we speak..
You'll like what we have cooked up! More power and less cost with some kits as much as 600 bucks LESS than last year!

[LarryR]

Great choice..
I am working on the finalities of the 2008-2009 engine kit program as we speak..
You'll like what we have cooked up! More power and less cost with some kits as much as 600 bucks LESS than last year!

WOHOO!!! sounds good. I will have to go back to your site to check out the new prices.