Hypothetical engine w/ $30k budget: bottom end

[BoxsterGT]

Steve@Rennsport-

I tried to find your ITB throttles on your Website, but could not.

Can you post some photos of them as for this 3.8 motor being discussed?

Thanks.

Len

[kojo911]

Steve/Bill, All,

Fell down the slope, pulled my arms in, and I'm rapidly tumbling. Bought a 993 twin turbo, we're going through the top end, adding garret bb turbos custom intake, injectors and computer tuning. It'll be mated to a G50 trans (thanks for your input bill/steve) w/ custom gearing top speed about 155mph. My hope is to keep the car under 2500lbs, it currently weights 2400lbs so well see. At any rate it should be fun. I'll post pix when I can. Here's one of the car.

[juicersr]

Kojo, isn't that the 'gumba' car that was in Excellence a few years ago? I thought that had a N/A 3.6 in it?

[kojo911]

yes it is, I'm the third owner since it was built, still only has 10k miles on the build. Sold the 3.6 to a fellow pelicanite, bought a twin turbo. Long story but the 915 tranny always bothered me, got a shortened g50 w/ custom gearing and guard lsd. Then it went into the "boy, wouldn't this car be great w/ a twin turbo" mode. I'll be happy when its' back togeter. btw the first thing to go was the personalized plates, not my style

[juicersr]

Welcome to the 'Slippery Slope Turbo Club'. I always thought that car was really cool, esp with all if it's widebody carbon and kinesis goodness. Also thought i would look really, really cool in black. Come on over to the 930 forum... we would love to follow your fall down the slope...er, i mean build. That's gonna be one fast rocket sled of a mutha at 2400 lbs!

[Steve@Rennsport]

Originally Posted by BoxsterGT

Steve@Rennsport-

I tried to find your ITB throttles on your Website, but could not.

Can you post some photos of them as for this 3.8 motor being discussed?

Thanks.

Len

Len,

Shoot me an e-mail and I'll send you some pictures of our ITB package.

[vreference]

As far as the 4.0L is too large for six cylinders argument goes - Does 5.3L sound radical for a V8? That's what the displacement would be if you tacked on another 2 cylinders. 3.8L works out to 5.0L for a V8 version of the same engine. Very average if you ask me.

As far as 400HP out of a N/A 4.0L Porsche engine; no doubt Steve knows a LOT more about building porsche engines than I do but 100+HP/Liter is being obtained on some very reliable daily drivers. Toyotas 2zz is 105HP/L and only revs to a fairly reasonable 7600RPM. BMW managed the same figure with it's 3.2L s54 at 8000RPM although I'll admit that's a fairly high-strung engine not known for it's low maintenance requirements. Throw in the s2000's 120HP/L and rock solid record in the mix for good measure and these are all factory production cars with a warranty backing them up.

The flat six isn't capable of this? Is it the heads? I realize the factory heads are pretty good but they are far from radical - it seems strange there aren't more aftermarket options considering how much money is floating around in the Porsche market.

[911nut]

Originally Posted by juicersr

Kojo, isn't that the 'gumba' car that was in Excellence a few years ago? I thought that had a N/A 3.6 in it?

Juice, that's Rhumba. I ran across the Excellence article today. With a tt it might be able to keep up with your 934

[boba]

Originally Posted by vreference

The flat six isn't capable of this? Is it the heads? I realize the factory heads are pretty good but they are far from radical - it seems strange there aren't more aftermarket options considering how much money is floating around in the Porsche market.

It's out there, how about pneumatic valve springs ala F1 in a 911 head. See these guys if $$$$$$ are no object.

www.eliteenginesystems.com

But that was not Bill's original budget.

[gtu935]

All good stuff here. Highlighted by Steve fron Rennsport and Tim T. I agree on all aspects. With the mods and Motec (being the best but very pricy) the budget will strain at 30K. Crank work is imperative, Good rods as well either Pauter or Carillo. NASCAR bearings not so much as your RPM limit doesn't warrant them. ITBs are great, very trick and will yield the most power but, a single throttle set up ie: 964 or 993 type will also yield plenty of power and will be more easily tuned. A high CR will be key in extracting a high power output.

Bill Rudtner

[red964]

id talk to Colin Belton at www.ninemeister.com and come away with a 4.0L+ and 450bhp ish.

[petevb]

Originally Posted by red964

id talk to Colin Belton at www.ninemeister.com and come away with a 4.0L+ and 450bhp ish.

I talked to him and looked into the 3.8L and 4.0L versions of that motor. Got quotes- neither is cheap. Also realize that at these power levels the motor will need rebuild/ refreshes at least every 25-30 hours. The cost/ performance curve on a n.a. air cooled 911 motor starts to get very steep beyond about 330-360 hp.

[red964]

sure, his 3.8 level with the ninemeister heads, motec, ITB etc would
probably see you towards 370bhp+ and be good for road use.

[beepbeep]

400hp from N/A 2v aircooled engine? I have no N/A expirience at that level but I bet it's going to cost cubic dollars ... cost/performance gets very steep and nonlinear there.

I assume slide throttles, lightweight valvetrain, biggest valves you can fit into the heads, twin plugs, Ti retainers, 906-like cams and Ti rods would be a good start. 4.0L kits have a reputation to be a bit one the edge?

I'll throw in a joker: I would bump compression to 13:1 and run it on E85.

But in the end, If I was to use that kind a budget, I would spend (healthy) portion of that money on lightening the car. Then I would build fairly reliable engine and hopefully still have same HP/kg ratio and lighter car.

[petevb]

Originally Posted by red964

sure, his 3.8 level with the ninemeister heads, motec, ITB etc would
probably see you towards 370bhp+ and be good for road use.

I have dynos showing ~425 hp at the motor from the 9M 3.8L; compression was on the high side for road use. This is with the 9M head and cam package as well as their cylinders and pistons. It should be noted here that some feel the 9M dyno is on the optimistic side...
The 4.0L adds a bit more power, largely though a different cam, but it really fills in the torque curve.

I agree you'd better have maxed out weight reduction before you consider spending money on this type of power. The knock-on effect of that much power (stronger transmission, more cooling, ie more weight, which then requires bigger brakes and bigger wheels, etc, etc) is not to be underestimated.

In the end the rebuild schedule is what got me, and they were upfront saying that they would see significant wear when pulling the motors apart at 25-30 hours vs some of the other options. There are other ways to get to those power to weight ratios, even normally aspirated...

[Jeff Alton]

I am one that thinks the dyno is optomistic. Nothing to base it on, but I see lots of dyno claims from english tuners that make me wonder.....

Anyone on this side of the pond used their heads? Done any dyno testing?

Cheers

[petevb]

Originally Posted by Jeff Alton

I am one that thinks the dyno is optomistic. Nothing to base it on, but I see lots of dyno claims from english tuners that make me wonder.....

Anyone on this side of the pond used their heads? Done any dyno testing?

Cheers

I know Geoffrey Ring of Racetek has a 3.8l version using mahle p&c with the 9m heads, etc. He flowed the heads and generally supports the 9M claims, though one could argue that he works with them enough that there may be a conflict of interest. He has posted dynos on rennlist that show 340 rwhp (roughly 400 crank by his estimate) with 93 octane gas. This is a bit behind a 3.8 RSR sprint motor on the same dyno by his reckoning.
I do believe the 9m heads are very good. Exactly how good is tough to say- it seems the US numbers might be a bit below the UK numbers when comparing claims.

[911teo]

Originally Posted by Jeff Alton

I am one that thinks the dyno is optomistic. Nothing to base it on, but I see lots of dyno claims from english tuners that make me wonder.....

Anyone on this side of the pond used their heads? Done any dyno testing?

Cheers

I also think their dyno is a little optimistic.

I am having my engine built by them. All 9M components. 3.8L.

I am not that interested in absolute dyno numbers.

Having said that i am planning on comparing my on the same dyno back to back my Ford GT and the 911 with the 9M 3.8L.

The Ford GT makes a conservative 650hp at the crank (couple of mods). We'll see where the 911 will fall.

Extrapolating from their previous build we are expecting between 390 and 410hp from the 911 on their dyno.

[petevb]

Looking forward to seeing how that goes- you're thinking that motor is a few weeks away? I almost went that direction before I was seduced by the dark side. It will be very useful to see numbers from the 9M vs an independent dyno.

-Pete

[911teo]

The engine is in the car and running.

We are waiting for a fuel pressure regulator but I'd say 2 weeks max and we'll have the 9M dyno results...