SIX VS. FOUR, when does the six win? Options

[Trekkor]

Some say go six, some say stay four or go BIG four.

At what point does the SIX take over?

I run a 90 hp four and have been told that my 'lil SIX will make me slower with my 130+ hp. PO says 245hp. Won't truly know 'til dyno day. Which may sway me.

What kind of weight increase are we talking about?

Will I enjoy the car more on the street with the SIX?
Because let's face it I run 1-2 a/x a month compared to my 200 miles street driving.

a/x season is coming to an end soon. I'll finish with the four.
My project will be during winter. If the SIX is bogus I'll put the four back in. (IMG:style_emoticons/default/confused24.gif) Only my time with my car hobby has been spent. ( A few bucks, too. ) (IMG:style_emoticons/default/idea.gif)

KT

[Brad Roberts]

HP to weight ratio....

90hp@ 2100lbs

130hp@ 2300lbs

It will always be easier to accelerate and stop less weight.

The biggest mistake made by newbie drivers... adding power before they can drive. It is much easier to add power than it is to add driver.


B

[VegasRacer]

You say 130 hp. PO says 245 hp. That's a BIG difference.

[Trekkor]

I understand the driver part, as I still am just a punk. (IMG:style_emoticons/default/wink.gif)

When I had Instructors on both my afternoon runs on Sat at Alameda I only lost 1 second compared to my runs without 200 plus pounds of Randal or Rob Ways ( sorry ).

With the added ponies why am I slower?

When does HP win out?

KT

[anthony]

I've been totally enjoying blasting around in the 911SC I just picked up. Unlike a stock 914, it effortlessly accelerates and moves through traffic. From 3000rpms to redline it's a damn rocket ship. It could only be better with about 250hp on tap. :-)

stock 914 2L (2100lbs) = 23 pounds per hp
stock 911SC (2600lbs) = 14 pounds per hp

To me if you are going to go with a six conversion you should go for at least a 3L or 3.2L engine but using the engine you have could be good for the initial shakedown.

It seems like it comes down to a coin toss. It costs $10-12K to install a used 3.2L engine. It costs about the same for a 200hp big four with nickies except you get a new engine and it only takes a few hours to install. The type IV is also a lot cheaper to repair/refurbish. Pick your poison.

[Trekkor]

You say 130 hp. PO says 245 hp. That's a BIG difference.

Yes it is. (IMG:style_emoticons/default/confused24.gif)
PO is no longer with us, so all info on build is lost.
245 is the surviving family rumor.

Trekkor

[anthony]

245hp is a big number. What engine configuration are you supposed to have?

[SirAndy]

At what point does the SIX take over?

it'll take over your WALLET when it's time to do a rebuild ...

(IMG:style_emoticons/default/rolleyes.gif) Andy

[Walter]

When does HP win out?

KT

Up to 2,7 ltr both engines can be made equally strong. The six will however always be heavier and therefore needs some extra hp to be equally quick.

The difference will eventually be reliability. The six will always have more reserve with that aspect. The four needs way more tricks to be reliable at the same hp rating. A big four will be high strung, whereas a six is just mildly tuned with about the same power.

Strangly (or logically) enough, thats where budget comes in: With Nikasils (standard on most sixes), dry sump (standard on sixes), mods to make the outdated underhead valvetrain lighter (well, you know what Porsche did for that one), a big 4 can be made very reliable and then probably costs about the same if you let others do the engine building for you.

Although this reaction may lead you to beilieve otherwise, personally I like the type 4 better. A lighter car (especially a type 4 with Nikasils) is always more fun to drive fast (IMG:style_emoticons/default/smile.gif) and as stated before, a type 4 can be build more easily by oneself than the six IMHO...

Good luck,
Walter

[ArtechnikA]

At what point does the SIX take over?

at the point on the dyno curve when the six starts producing more power...

stroke and compression being equal (which they mostly are on the 1,7/1,8) a big piston will produce more torque than a little piston. a 2,0 4 will produce more low torque than a 2,0 6. the 6 is starting to get into the meat of its power curve about where a D-Jet cam is falling off the top.

on the road - plus or minus a little - the crossover point is around 70-ish -- this is why 4's tend to be quicker at AX - where the speeds rarely exceed 70 and the 6 carries more weight.

no matter what you do - there will always be SOME engine that makes more power and goes faster than yours. enjoy what you've got and learn to drive it - this includes keeping it in a rev range that's appropriate for the task at hand.

[914Timo]

I have to say that the six is a lot more difficult engine to maintaina. Think about valve adjusting ..... (IMG:style_emoticons/default/mad.gif)

And there is tons of more places where it can drop oil (IMG:style_emoticons/default/wacko.gif)

But, I love my six. I dont even need a radio. I love the song of six (IMG:style_emoticons/default/wub.gif)

[cnavarro]

Hey Walter, glad to see you here!

I'm going to stay out of the /4 vs /6 debate. I can truely say I can be neutral now that I made cylinders for both :-)

Charles Navarro
LN Engineering
http://www.LNengineering.com
Aircooled Precision Performance

[Tom Perso]

HP to weight ratio....

90hp@ 2100lbs

130hp@ 2300lbs

It will always be easier to accelerate and stop less weight.

The biggest mistake made by newbie drivers... adding power before they can drive. It is much easier to add power than it is to add driver.


B

I am a perfect example of too much power and not enough driver...

A 2270 in the 914 on R compound tires and it was only my second auto-x. The car was a handful and it literally shot from corner to corner... I couldn't keep up with it!

Tom

[brant]

I think the -6 really starts to take over when you factor in the higher redline and gearing advantages of a big track.
b

[Mark Henry]

All I have is a stock /4 engine with a bit of a cam and the SDS EFI and the power rocks. They have dyno days at the local rolling road and I want to try it out to see what Hp I now have, my guess is 110-120. It was enough to keep up with a Ferrari 328 over the weekend, I'm pretty sure he would have cried if he knew my 914 is only a 4 banger. (IMG:style_emoticons/default/biggrin.gif)

I almost jumped on the six bandwagon when I first got my teen, but the costs were a bit too much for me. I might have been able to do a low budget /6 for the cost of my new 2.6 nickies engine, still it would be a lot more work fitting it in.

One thing about a /4 though, it will always sound like a VW at idle. The sixes do sound cool.

[Jake Raby]

Keep it a 4, or slap in a V8... The six conversion doesn't even get a wink from me..... atleast the V8 makes enough power to afford the weight and you can build one dirt cheap...

"The only replacement for displacement is weight reduction" Keep that in mind and the 4 is very promising IF IT IS DONE RIGHT! Not many people hold the keys to unlocking the -4 in power and reliability. I have a full set in my pocket 24 hours a day.

[mack914]

Doing a 6 conversion. Putting the drive train in today. May not be doing all the right things. But, one thing I do know is the sweet sound of that 6 is worth the price. (IMG:style_emoticons/default/wub.gif)

[Jake Raby]

Must have never heard a big four done right.. It'll drown the six in carbs alone.

[scotty]

At what point does the SIX take over?

...sound (IMG:style_emoticons/default/wink.gif)

I drove a '75 1.8 for 15 years. I loved that car. The only time I wished for more power was at high altitude and/or climbing steep hills "in pursuit."

I now have a '74 with a 2.7 six. It's more fun/money/tinkering. It also makes me pay more attention when I'm driving. Stupid moves that a stock 1.8 -4 would let me get away with become much more "interesting" with the -6 (not driving a 914 for 10+ years doesn't help one remember skills).

Gas mileage is down with the -6, but the grins per mile index is waaay up.

I can imagine the grins to be had with an 8.

[anthony]

It was enough to keep up with a Ferrari 328 over the weekend

The ferrari must have not been trying. A 120hp 914 can't keep up with a 250hp Ferrari unless it's on an autoX course.