I am sure ths has been discussed before but I couldn't find anything using the search. So, has there been a comparison done between a 911 six and big four, like Jake Raby's engines? Looking at:
1. Overall cost of engine (plus consideration of the cost of the conversion to a six from a four)
2. power hp/tq
3. engine life
4. other issues?

This is a recurring topic. When you did the search, did you select "any date"? The default searches only 30 days back.


Andrew

I went through this a while back and here is what I found. Both the 2.7L four I had and my 2L six have 185 HP at the rear wheels on the dyno. The four would last about two race weekends and need work. The six has been in 1 1/2 years and runs right along as it was made to rev to 9000 RPM and I rarely go over 8K. The four was easier to drive, only had to shift into fourth once at Willow Springs to go over the hill as the four had much lower and flatter torque curve. With the six I shift all the time, even into 4th at turn nine. The cost of five years of engine work on the four was probably much higher than the cost of the six conversion, but I have never added it up. Both engines were dry sumped with front oil coolers so no difference there. Many will say a big four can be made to last but with road racing the high horse power fours will not last as long as a comparible six. If you cut the power back to say 130 at the rear wheels they would last longer and to be competitive really cut weight of the car down to 1800 pounds, you can win against the six's easily.

I have done extensive research on this subject. The 6 is the way to go in my opinion especially if you think you will ever bring the car out to the track. Regardless of the claims you hear the Type 4 is not up to the rigors of extensive track sessions if you want an engine that will last more than a season or two.

If resale value is a consideration regardless the reputation of a given type 4 engine the car wont hold same value as a 6 conversion. 6 conversion can be done very cost effectively when compared to a well bult big Type 4 such as the ones from Jake.

If money doesnt mean anything to you then a big Type 4 is cool and Jake is one of the best around. I just cant justify the expense of a well built big type 4 when I look at the benfits and costs of going with a 6 conversion.

QUOTE (phantom914 @ Aug 16 2005, 10:06 AM)

This is a recurring topic. When you did the search, did you select "any date"? The default searches only 30 days back. Andrew

Yep, found a lot of information on six conversions and a lot on bigger fours, nothing with a comparison of the two.

This is always a fun topic, because some people lose all control and sense of reason and take offense like it's a personal attack on their family or something.

I've had a stock 1.8 and 2.0 FOUR. Very fun car to drive.
Now I have the 2.0 SIX.
To me there is no comparison SIX vs. stock FOUR.
The SIX is free revving, high rpm's with faster acceleration. Then there is the SOUND of the Webers, big fan and chains. Try to take your stock FOUR to 7300 rpms and see what that sounds like...

Built FOURS- that's another story in itself.

Consider this: you can do a budget SIX conversion and buy one, maybe two good running back-up 2.7 motors at $4000 each for the price of a custom built big FOUR. No joke.

My plan is to always have a SIX.


KT

There are many people out there with +200k miles on 3.0/6 street motors, that still pull 200+ hp.

In HiPo /4 motors, you have to have head work done often... hell... in non-hipo /4 motors.. you have to do head work.. often.



tic tic tic tic..


M

while i agree with most of the above, the big /4 has at least 2 advantages ...

- less weight
- better torque curve (much better low end torque)

- for street use, it's a toss-up. both can be a lot of fun for the money and both can be build to be reliable ...
- for the big track, go with a big /6 as you'll like the higher rpm HP ...
- for AX, go with the big /4. less weight and better low end torque will more than make up for less high rpm HP ...

just my 2 cents of course ...
Andy

Generally, I think a stock six will outlast a built 4 (Jake's motors may be the exception, but cost as much as a six conversion). Power can be similar. 4 weighs less. A highly tuned motor can be a PITA for street use. These are all gross generalizations....it's a close call in my opinion.

QUOTE (trekkor @ Aug 16 2005, 07:56 AM)

This is always a fun topic, because some people lose all control and sense of reason and take offense like it's a personal attack on their family or something.

Ah yes... the 914world.com version of the 'scientific method'.

Step 1: Someone asks a very good question.
Setp 2: Side 'A' makes outlandish unsubstantiated claims.
Step 3: Side 'B' makes outlandish unsubstantiated counter-claims.
Step 4: Both sides comence with personal attacks.
Step 5: Third parties request objective data for evaluation.
Step 6: Sides 'A' and 'B' lynch third parties.
Step 7: In the future, new club members read old thread.
Step 8: Some of these new readers accept the unsubstantiated claims as gospel.
Step 9: Rinse and repeat.

-Ben 'gimme unbiassed objective data' M.

I won't even go there this time!!!!!

All I'll say is that there is NOTHING on this earth better than handing the driver of a six cylinder car his ASS on a silver platter with a 4 cylinder pushrod engine......

QUOTE

Ah yes... the 914world.com version of the 'scientific method'

unbiased?...objective?.......no such thing. My dad used to say "I have an open mind...everyone's entitled to their own stupid opinion"

QUOTE (airsix @ Aug 16 2005, 09:37 AM)

'gimme unbiassed objective data'

does my butt count as a "unbiased scientific method"?

if so, i stick to what i have said ...
Andy

QUOTE (Jake Raby @ Aug 16 2005, 09:43 AM)

All I'll say is that there is NOTHING on this earth better than handing the driver of a six cylinder car his ASS on a silver platter with a 4 cylinder pushrod engine......

i don't know ...

i'd rather spend a whole night in bed with 3 cute girls ...
Andy

For purely street use, one consideration against the six is noise. That big fan pointing directly at the firewall is LOUD. I had relatively little intake noise and little exhaust noise on my 2.4 CIS Six, yet you still had to shout at the passenger at freeway speeds because of the fan noise. For a weekend toy, this is tolerable. For a regularly driven car, however, it gets very tiring. With K&N filtered Webers, you have even more noise.

Granted, these are all wonderful noises; few things sound better than a Six wound out. Too much of a good thing, IMHO.

Comparing the costs of a Six conversion v. a big four by saying the four is more expensive, however, is stretching the point a bit. If you get lucky and find a Six that doesn't need to be rebuilt right now, then you could do the swaps for about the same amount of money (assuming a very nice Jake-built four). However, with the four, you'd have a brand-new engine that would likely last you 100K miles before needing attention. With the Six, you'd have an engine that would probably give you no more than 50K miles before requiring a $10K rebuild. It could easily give you only 1K miles before needing that money spent. Roll of the dice.

Comparing like for like, a fresh SC engine with all of the conversion parts is going to run you $15-20K. A new Jake-made 2.3-2.4 four will cost you half that, even with Nickies and ceramic coated everything. Both will live longer than is practical to worry about (how long will it take you to run up 100K miles on either engine?). Granted, the SC will make more power (and certainly more torque), but it's also twice as much.

QUOTE (lapuwali @ Aug 16 2005, 09:00 AM)

For purely street use, one consideration against the six is noise. That big fan pointing directly at the firewall is LOUD. I had relatively little intake noise and little exhaust noise on my 2.4 CIS Six, yet you still had to shout at the passenger at freeway speeds because of the fan noise. For a weekend toy, this is tolerable. For a regularly driven car, however, it gets very tiring. With K&N filtered Webers, you have even more noise.

Well, you can always get those walkie talkie things for motorcycles to communicate to the passenger...

I guess one man's noise is another man's music.... Those webers sucking air and the rattle of the chains are still music to my ears.. Radio? we don't need no stinkin' radio!

QUOTE (maxwelj @ Aug 16 2005, 09:15 AM)

I guess one man's noise is another man's music.... Those webers sucking air and the rattle of the chains are still music to my ears.. Radio? we don't need no stinkin' radio!

Agreed! no radio! set off a car alarm last night with my exhaust .
Ferg

As a strict cost comparison, the next time you are in San Diego you are welcome to stop buy and you can total up the reciepts for the four cylinder and for the six cylinder engines over the years. I am guessing that the four cost 3 times in maintenance over the same period of time that the six does? Besides, it is NOT the engine, it is the driver that wins the races!

QUOTE (airsix @ Aug 16 2005, 12:37 PM)

-Ben 'gimme unbiassed objective data'  M.

There is a Birdite that will back up claims of sub 300k/m 3.0 motors still pulling cars around. I won't mention names, because only the worst kind of troublemaker, would force Dxxx Dxxxxxxx to get into this conversation.

ooops...

Given a budget of $10k, a /6 will get you a -bunch more performance- that you can count on being there... in 30k miles, when the HiPo/4 needs head work, to get the boom-boom back, and at 60k, when the HiPo/4 needs head work, to get the boom-boom back... and at 90k, when you are freshening the heads in the HiPo/4 to get the boom-boom back, that won't come back, because you need a new bottom end...

A normally functioning 3.0/6 puts out more power than you can get out of a HiPo /4.

It's unfair, really. We are talking about built motors, against stock here.. stock vs stock leans even more to the /6.

It's ok to love something different than everyone else, remember before you blast me, I went out of my way, to buy a /4, when I could have had a /6 for about $10.00 more. I like the sound of a fresh /4, when it isn't grenading.



My opinion has been paid for, many times over.

And James, I think you are a little high on what a /6 costs, and apparently quite low on what a real performace /4 costs... 3.0/6, is a core + around 7500, vs about 3/4ths the HP from a $15k /4.

M

I believe you need to look the entire scope of the conversion which I think is over looked. Don't just compare engines, compare the work involved. You can do a Big-4 change out in a weekend by yourself. You better call some friends if you want a -6 in a weekend.

Look at it this way: Take a Big-4 to a shop and ask for a price to install it. Take a -6 to a shop and ask for a price. Do they still cost the same?

You also need to think about the other associated parts and pieces that go into the -6 upgrade for track use. -6=more weight=bigger brakes and five bolt wheels and an upgrade here and there and everywhere. $$$

But once again it all come back to what you're going to be doing with the car.

Paul

A couple of years after buying a new '73 2.0L, I roomed with a guy that owned a '70 six. Both cars at the time were stock (His six actually had fewer miles), and both were black. I tried driving one, then hop into the other, and back again. Near as I can recall (some 30 years later), the six was by far the stronger car. I was always amazed at how much stronger the six ran, given they were both the same displacement. Seat of the pants side-by-side test. I would have prefered the six any way you cut it. FWIW.

Andy

QUOTE (john rogers @ Aug 16 2005, 09:19 AM)

As a strict cost comparison, the next time you are in San Diego you are welcome to stop buy and you can total up the reciepts for the four cylinder and for the six cylinder engines over the years. I am guessing that the four cost 3 times in maintenance over the same period of time that the six does? Besides, it is NOT the engine, it is the driver that wins the races!

John, you're talking about race engines, and I'm not. Jake has claimed that one of his engines will go 100K miles in "normal" use, which seems to mean street and some AX, with maybe a track day here and there. I have no reason to doubt this figure. This is an expensive ($8K) engine with Nickies and ceramic stuff in it. I have no doubt an iron-barrelled highly-stressed engine will have a much shorter lifespan, esp if road-raced. That a Six will hold together for 2-3x longer than a Four under racing conditions is good info, but not necessarily relevant unless the original question was only about track-only engines. Even if that's directly applicable to the street, if Jake's numbers are reasonable you'd see 200-300K miles out of a Six in street use. For some Sixes (like the SC), I'd believe that number.

However, if I can spend $8K on engine A and get 100K miles, or $20K on engine B and get 300K miles, I'd still opt for engine A, since that 100K miles would likely last me 10-15 years in a 914. I'd be dead (or just too old to care) by the time engine B needed a rebuild.

QUOTE (redshift @ Aug 16 2005, 09:19 AM)

QUOTE (airsix @ Aug 16 2005, 12:37 PM) -Ben 'gimme unbiassed objective data'  M. There is a Birdite that will back up claims of sub 300k/m 3.0 motors still pulling cars around. I won't mention names, because only the worst kind of troublemaker, would force Dxxx Dxxxxxxx to get into this conversation. ooops... Given a budget of $10k, a /6 will get you a -bunch more performance- that you can count on being there... in 30k miles, when the HiPo/4 needs head work, to get the boom-boom back, and at 60k, when the HiPo/4 needs head work, to get the boom-boom back... and at 90k, when you are freshening the heads in the HiPo/4 to get the boom-boom back, that won't come back, because you need a new bottom end... A normally functioning 3.0/6 puts out more power than you can get out of a HiPo /4. It's unfair, really. We are talking about built motors, against stock here.. stock vs stock leans even more to the /6. It's ok to love something different than everyone else, remember before you blast me, I went out of my way, to buy a /4, when I could have had a /6 for about $10.00 more. I like the sound of a fresh /4, when it isn't grenading. My opinion has been paid for, many times over. And James, I think you are a little high on what a /6 costs, and apparently quite low on what a real performace /4 costs... 3.0/6, is a core + around 7500, vs about 3/4ths the HP from a $15k /4. M

I can drop a "HiPo" /4 directly into the engine bay with no more money than the cost of the engine. A 3.0SC would require a lot more money for a lot more parts to do the swap. KEP kit, engine mount, exhaust, oil tank, plumbing, etc. The number bandied about here often is $10K to do a Six swap "properly", at a minimum, and I KNOW rebuilding an SC properly would be $10K minimum. Hence, $15-20K.

I SAID you'd get more power out of the 3.0/6 than the $8K /4. At twice the price. 140hp v. 180hp, more or less. More power costs more money. No surprise there.

$8K for a 100Kmile, 140hp four are basically Jake's numbers. Argue with him if you think that's not so. I'm sure a 180hp four would be a lot more. More power costs more money...

James, again, you aren't even in the same ball park.

An $8k /4 won't get you anything like the preformance of a $10k /6.

As far as I can tell, it costs about $15k for a /4, that even approcaches the performance of the /6, and it won't last. (the performance)

So, around 200hp, that needs alot of service in 100k miles, to stay that way, or 200+ hp, that requires less service, and lasts in situ, 3x as long.

We need to make a points system, and itemize.

In your above post, DIY /4, vs pay somebody /6. Time is worth something.


M

ok here's my take...

if you have unlimited resources and max hp is your goal, then a /6 may be the smartest money... more reliable and gobs of power


if you have a more realistic budget and plans, then it's a sliding scale...

I think the higher your budget is, the more a /6 is feasible, if you are saying "what can I get for 6k? then you would want a /4... because at that $$ a 4 is all you can afford... I think at 8-10k it's almost a wash, because the conversion costs associated with a /6 + the engine will get you about the same hp as a 10k /4... (I really don't think the weight difference is NEARLY as much of a consideration unless it's a full-time racer, not a street car)

in other words, it's all about the dolla,dolla bills... the more you have, the more engine you can get.

now, what do I want? one of each... a Raby 4 and a 3.2 six warmed up in my garage.

I have no idea what Jake's engines cost, but I'm sure they are worth every penny.

unfortunately, I don't see when I'll be able to afford that many pennies...

a Raby Kit is feasible and a good buy for the 6k range... try putting a /6 in a car for 6k... if you do, you are either lucky or did it a piss-poor way.

This is a big problem here, because when anyone says /4, the topic always goes to Jake, and it's UNFAIR to Jake. Jake isn't the designer of either engine, and has no control over physics.

It's not personal, and I think we all respect him for his overt enthusiasm, and his quest to wring out everything that he can.

Just an aside.

Jake.



M

You guys are all thinkin too small. Let's see, 400 horses, $8k, hmmmm, how could that be done?

hahahaha

You need a $12k transaxle.


M

I had to do it. This clusterfuch was developing much too slowly, and I just don't have much patience today.

What works better in that one; tap water, or Perrier?




M

I've got a solution, just buy a 911 to go along with your 914...there, you got a 6 and a 4

QUOTE (redshift @ Aug 16 2005, 01:00 PM)

What works better in that one; tap water, or Perrier? M

20 year old Jack Daniels, actually. Know where I could find any?










Sorry John. I have shamelessly polluted your thread for my own enjoyment. I promise to try very hard to stop now.

FYI- The cost between a 180HP/4 and a 140 HP/4 isn't but about 2K and thats the difference in head work primarily since 90% of the other components will handle 180HP just as well as 140.

Now, going over 180 HP RELIABLY almost dubles the cost of the 140HP engine because we have to use exotic materials to attain the goal and retain RELIABILITY AND LONGEVITY...

I have built many 911 engines in my time, but none newer than a 2.7..... I chose long ago to stick with the /4 because I totally understand the engine and all its parts- Of course I'm biased to a /4 engine because I love them.

I will say that a /4 thats not properly designed or well built is a nightmare waiting to happen- those nightmares keep my doors open because I repair those mistakes all the time.

QUOTE (aircooledboy @ Aug 16 2005, 09:57 AM)

You guys are all thinkin too small. Let's see, 400 horses, $8k, hmmmm, how could that be done?

Well if you are going to pull that genie out of the bottle, I can build and install a 400hp Subaru engine in my car for half that price!

But back on topic...
I am really glad to see this 4 vs 6 topic being discussed, as this is what I am currently going back and forth about. I fall into the portion of people here that want good solid power for the street with an occasional foray onto the track or auto-x on the weekends.

With those needs, I am not going to put $10k into either engine. I am comparing a mild big bore build out of the 2.0l 4 to a 2.4l E conversion. Obviously the 4 is going to be cheaper, but I am left wondering if it will be enough power for me. In my world it goes back to the horsepower per $$$ comparison coupled with the lifespan of the motor. These days I am leaning towards the 6. It will cost me $4-5000 more to convert and get running, but once it is done, I think I will be happier...

I've done the SIX conversion for around $4k including the motor.

What can you build for that?
I won't spend $10k to rebuild any SIX.
I'll just buy a used $4k 2.7 with a 90 day warranty from Parts Heaven...In 90 days, believe me, we'll know if it will last.

Can a 2.7 FOUR be built for $6500? Someone will tell me.

KT

QUOTE (redshift @ Aug 16 2005, 12:56 PM)

This is a big problem here, because when anyone says /4, the topic always goes to Jake, and it's UNFAIR to Jake. Jake isn't the designer of either engine, and has no control over physics. It's not personal, and I think we all respect him for his overt enthusiasm, and his quest to wring out everything that he can. Just an aside. Jake. M

In my orginal post I put Jake's name in there because I think he is generally reguarded at the person that is making the biggest improvements with type 4 engines. I did NOT do it to put him on the spot or anything like that. That being said maybe we should look at this in another way.

What are the options for engines under 200hp and what are the options for over 200hp? Can a /4 equal the power of a six? I am pretty sure it can to a point, but what is that point? I just threw out 200hp but is there a limit?

Excluding turbo charging and all that V8 stuff. Of course.

Oh,
and one thing to add. I don't know what shops people are using for their 6 rebuilds, but those $10-15k number seem a bit high, unless you are talknig full blown race build. We have a rebuilt 1976 2.7S engine here for $6500, no core, and a rebuilt 3.0l for $9000. I am not trying to push product here, but just am wondering where those higher numbers are coming from???

QUOTE (aircooledboy @ Aug 16 2005, 01:14 PM)

QUOTE (redshift @ Aug 16 2005, 01:00 PM) What works better in that one; tap water, or Perrier? M 20 year old Jack Daniels, actually. Know where I could find any? Sorry John. I have shamelessly polluted your thread for my own enjoyment. I promise to try very hard to stop now.

I would prefer Grey Goose Vodka myself, let's just say I had a bad experience at my fraternity house with a bottle of Jack.

LA Dismantlers... (disclaimer) if you go over there, and see the motor you want, in the car, to verify milage, and...

You can get a 3.2 with real low miles for around $6.5k with all the goodies. Make sure it runs, because alot of the wrecks they get are a flat 911 shaped thing, with an engine lid, and internals can do bad things, on impact.


M

QUOTE (Matt Monson @ Aug 16 2005, 02:20 PM)

We have a rebuilt 1976 2.7S engine here for $6500, no core, and a rebuilt 3.0l for $9000. I am not trying to push product here, but just am wondering where those higher numbers are coming from???

And there is the 3.0 I am talking about.


M

Regarding six prices.....I just bought a very low mileage 3.0 for $3500. An exceptional deal maybe, and a bit of a gamble, but they're out there.

I switched from a 2 liter 4, to a 3 liter 6 turbocharged engine and just installed a blow away stereo with 2-5.25", 2-6.5" Alpine type r speakers and 2- 8" Quart subs.

There is no way I would rather have a 4 now. And I do not wish to not have a stereo. If I want to listen
to the engine all i have to do is turn the stereo off.

I would still enjoy driving a 4, but prefer the 6.

QUOTE (redshift @ Aug 16 2005, 01:24 PM)

LA Dismantlers... (disclaimer) if you go over there, and see the motor you want, in the car, to verify milage, and... You can get a 3.2 with real low miles for around $6.5k with all the goodies. Make sure it runs, because alot of the wrecks they get are a flat 911 shaped thing, with an engine lid, and internals can do bad things, on impact. M

Over here on the right coast you can get a 3.2 with all the goodies for $6800. So given that and then then you have the engine mount, oil tank, additional oil cooler, and ????

Yeah, you need an oil tank, all the fittings, a cooler, and mounting, and a mount, and.. yeah, the Pelican conversion guide has the list.

I thought this thread was a comparison of motors.




M

QUOTE (redshift @ Aug 16 2005, 01:59 PM)

Yeah, you need an oil tank, all the fittings, a cooler, and mounting, and a mount, and.. yeah, the Pelican conversion guide has the list. I thought this thread was a comparison of motors. M

here I thought it was a comparison of the costs... hp vs cost has to include the cost to convert...

if a /6 was just a "drop in" it would be a much easier decision.

QUOTE (tat2dphreak @ Aug 16 2005, 12:04 PM)

QUOTE (redshift @ Aug 16 2005, 01:59 PM) Yeah, you need an oil tank, all the fittings, a cooler, and mounting, and a mount, and.. yeah, the Pelican conversion guide has the list. I thought this thread was a comparison of motors. M here I thought it was a comparison of the costs... hp vs cost has to include the cost to convert...

IMHO,

the cost to convert should not be included..the oil tank, the engine mount and other related items are a 1 time purchase...the only thing that should be compared is the cost of the motor and related costs to keeping the motor alive

I wonder how many of those hi-po type 4s can be dropped in the engine bay without the use of an external oil cooler.


On the other hand you could put in a Subaru 2.5 and get 170 HP out of the box for only marginally more effort than a 6 conversion and a fraction of the cost. Not to mention a fraction of the cost of a type 4 that can put out that power. There's no valves to adjust, just a belt to replace every 100k miles. Not to mention a modern electronic fuel injection and ignition system. No more caps and rotors, no distributors, no timing adjustment, no points (or pertronix), etc. etc. And 100k miles. Easy.

Oh and don't forget the weight savings. I haven't measured myself but apparently, lighter than a type IV....

Then there's the whole thing about new cams for around $500 and getting just north of 200 HP.

Sure its not a Porsche motor, and yes it is water cooled. If you can live with those issues then it makes for a very tempting substitute.

Even better is a WRX motor, but they are a bit more expensive, and probably need a front mounted radiator. With a 2.5 NA you can get away with the radiator right smack in front of the engine.

-Tony

QUOTE

I wonder how many of those hi-po type 4s can be dropped in the engine bay without the use of an external oil cooler.

He must have never experienced a DTM on a TIV engine....

Here is a testament to a DTM on a 2270 160HP TIV running NO EXTERNAL cooler in 100 degree heat at 75+ MPH for extended amounts of time..
http://www.shoptalkforums.com/viewtopic.php?t=90197

QUOTE (redshift @ Aug 16 2005, 01:59 PM)

Yeah, you need an oil tank, all the fittings, a cooler, and mounting, and a mount, and.. yeah, the Pelican conversion guide has the list. I thought this thread was a comparison of motors. M

It is, but the inital cost of those items has got to be factored into the decision, IMHO. I know some would disagree but total cost of ownership is what I was thinking of.

If a typical 6 coversion goes for about $10k (from what I have read here) and that is for a 3.0l engine which in stock form put out 188hp according to Porsche what would the cost of a 180 hp 4 be? How long will the 180 hp 4 last? Will the tq curve and hp in the 180 hp 4 be "streetable"? If the answer is much cheaper, just as long, and just as good then the 4 is the best bet.