Cross roads between a big /4 and a big/6, Share your experience Options

[seanpaulmc]

Seems like the choice is clear - you need a second shell. (IMG:style_emoticons/default/evilgrin.gif) (IMG:style_emoticons/default/biggrin.gif)

[Montreal914]

Yes, this is a good turnout of information. I really appreciate. One thing I need to dig up is what is involved in the 6 conversion, more specifically a 3.2.

My quick list is:
Engine mount
Oil tank
Oil lines
Headers/hex
Muffler
Engine tin
Clutch/flywheel adapter to the 901
High torque starter (maybe?)
Gearbox bell housing modification for some 3.2 sensor??
Shift linkage rod modification
Oil cooler elbow (or is the 3.2 different?)
Oil thermostat
Oil lines/front cooler
Accelerator cable?
Cables heat shielding sleeve
Fuel line size?
3.2 fuel pump
Harness to car
DME installation
3.2 Tachometer
Air filter modification?
Heating blower connection to Hex.

I am sure I am missing a few items but that is what is coming to mind at the moment. I will have questions about all of the above items. I did search 3.2 conversion threads but haven’t found one that was very complete… (IMG:style_emoticons/default/sad.gif)

I am not saying this is the route I am going, just establishing what is involved. Once I have the full picture, then I will be able to make a decision. (IMG:style_emoticons/default/smile.gif)

Yes, the big four is straight forward, especially since I have all the bits for it except that nice plenum Eric is teasing us with. (IMG:style_emoticons/default/poke.gif) From the picture I am recognizing a Subaru STI center and 3D printed adapters to the standard DRLA manifold. I would assume the STI throttle body would be used too. Just wondering why the injectors aren’t lower in the DRLA manifold. (IMG:style_emoticons/default/confused24.gif)

Fun stuff! (IMG:style_emoticons/default/driving.gif)

[Montreal914]

Seems like the choice is clear - you need a second shell. (IMG:style_emoticons/default/evilgrin.gif) (IMG:style_emoticons/default/biggrin.gif)

…and a lawyer (IMG:style_emoticons/default/laugh.gif)

[mepstein]

(IMG:style_emoticons/default/agree.gif) with Bob.

The "Deep Six" and "7R" is "the" wheel fitment for a narrow body super car. the offset on the face is identical so the 7 in the back looks just like the 6 up front. We have the same tires on the above car that I have on my RS pictured below. 205 up front and 215 in the back.



The stroker 2258 builds have amazing hp. All with modern EFI. The new intake is wrapping up. We'll begin testing next week. Sneak Peek here first.




All this coming from a dye-d in the wool flared six guy. I'm looking forward to my 2.3 Narrow Build (IMG:style_emoticons/default/smilie_pokal.gif)

That's really cool.

[gereed75]

Wow. Really cool Eric.

[mepstein]

[quote name='Montreal914' date='Sep 5 2024, 07:32 PM' post='3165770']
Yes, this is a good turnout of information. I really appreciate. One thing I need to dig up is what is involved in the 6 conversion, more specifically a 3.2.

My quick list is:
Engine mount
Oil tank
Oil lines
Headers/hex
Muffler
Engine tin
Clutch/flywheel adapter to the 901-kep or pms kit
High torque starter (maybe?) or regular 911 starter
Gearbox bell housing modification for some 3.2 sensor?? - 10 minutes with some small power tools.
Shift linkage rod modification - straight rod
Oil cooler elbow (or is the 3.2 different?) Ben does this. Use the carrera cooler and have him weld on the fitting
Oil thermostat
Oil lines/front cooler - You can always get the car running and then add in a cooler.
Accelerator cable? - Rich Johnson makes a nice kit
Cables heat shielding sleeve
Fuel line size?
3.2 fuel pump
Harness to car - PMS
DME installation drill a hole through the dimple at back of floor pan.
3.2 Tachometer - You can use any 911 tach or use a 914 tach with a tach adapt.
Air filter modification? 4" tube plastic tube. Flaps sells a kit for $15 and you cut off the bend on a chop saw.
Heating blower connection to Hex. Drill a 1" hole in your flapper boxes to duplicate a 914-6 heat flapper box.

Add in the brass oil line restrictor that's on 911 oil lines.

It's all been done many times. Maybe not a single thread of everything but it's all out there and plenty of people who will answer questions.

[VaccaRabite]

Second year with the EFI 2.3 /4.

I really like it.

You do NEED an oil cooler though. I'm running a setrab cooler behind the drivers side tire, and its not really enough. Oil is on the hot side of aircooled acceptable on those long hot and humid summer drives up the mountains. I'll reinstall the fan pack on the oil cooler after this season and that will solve the heat issue. Front mount would also do it, but I really don't want to loose the trunk space up front.

Zach

[MoveQik]

I think the sweet spot for the 914 is a 3.2L /6 with FI, it just feels like they all should have come with one. It's a perfect fit to the car.
(IMG:style_emoticons/default/driving.gif)


PS: And for a street driven 914, the 3.2L doesn't need a front mounted oil cooler, the stock oil cooler works just fine.

I agree with Andy. I ran my 3.2 with stock fenders, 901 and 16x6's for years and it was excellent. Of course I couldn't leave well enough alone and have gone bigger since but it wasn't necessary.

[IronHillRestorations]

I’m a fan of 3.0’s and 3.2’s with Motronic, but it’s got pricey to do a six conversion. Big fours aren’t cheap either, but much fewer ancillary parts to get.

[Montreal914]

Found some good threads an info in the garage.

I understand the fuel pumps needs to be matched to the engine and will fit in the 75-76 front fuel pump acces cover (IMG:style_emoticons/default/smile.gif) . Does the tunnel lines need to be larger? I have the SS ones already and was hoping to reuse.

Accelerator cable, it looks like patssle (hasen't logged in in two years (IMG:style_emoticons/default/sad.gif) ) figured a way to just loop ~180 degrees is /4 cable and brought it in trough the bell crack rod opening in the tin (picture below). Seems like getting the cable directly to the TB would be the simplest, lightest, cost effective way to do it. (IMG:style_emoticons/default/confused24.gif) That being said, it doesn't look like his setup is a 3.2 but still...

[Shivers]

(IMG:style_emoticons/default/agree.gif) with Bob.

The "Deep Six" and "7R" is "the" wheel fitment for a narrow body super car. the offset on the face is identical so the 7 in the back looks just like the 6 up front. We have the same tires on the above car that I have on my RS pictured below. 205 up front and 215 in the back.



The stroker 2258 builds have amazing hp. All with modern EFI. The new intake is wrapping up. We'll begin testing next week. Sneak Peek here first.




All this coming from a dye-d in the wool flared six guy. I'm looking forward to my 2.3 Narrow Build (IMG:style_emoticons/default/smilie_pokal.gif)

Hmmmm, maybe you can turbocharge a 914

[ClayPerrine]

Found some good threads an info in the garage.

I understand the fuel pumps needs to be matched to the engine and will fit in the 75-76 front fuel pump acces cover (IMG:style_emoticons/default/smile.gif) . Does the tunnel lines need to be larger? I have the SS ones already and was hoping to reuse.

Accelerator cable, it looks like patssle (hasen't logged in in two years (IMG:style_emoticons/default/sad.gif) ) figured a way to just loop ~180 degrees is /4 cable and brought it in trough the bell crack rod opening in the tin (picture below). Seems like getting the cable directly to the TB would be the simplest, lightest, cost effective way to do it. (IMG:style_emoticons/default/confused24.gif) That being said, it doesn't look like his setup is a 3.2 but still...

The factory linkage for a 914-6 works with a 3.2. The 914-6 cable linkage was setup to adapt the 911 linkage to the 914-6 mid engine layout.

Easy enough to do and it uses all factory parts.

[Montreal914]

Found some good threads an info in the garage.

I understand the fuel pumps needs to be matched to the engine and will fit in the 75-76 front fuel pump acces cover (IMG:style_emoticons/default/smile.gif) . Does the tunnel lines need to be larger? I have the SS ones already and was hoping to reuse.

Accelerator cable, it looks like patssle (hasen't logged in in two years (IMG:style_emoticons/default/sad.gif) ) figured a way to just loop ~180 degrees is /4 cable and brought it in trough the bell crack rod opening in the tin (picture below). Seems like getting the cable directly to the TB would be the simplest, lightest, cost effective way to do it. (IMG:style_emoticons/default/confused24.gif) That being said, it doesn't look like his setup is a 3.2 but still...

The factory linkage for a 914-6 works with a 3.2. The 914-6 cable linkage was setup to adapt the 911 linkage to the 914-6 mid engine layout.

Easy enough to do and it uses all factory parts.

I understand that, but it seems like a lot of pivot points for something a properly routed cable to the TB could do. (IMG:style_emoticons/default/confused24.gif)

I see Rich Johnson seels a replica of all this but, starting from nothing, this adds up to ~$500 to route a bycicle cable to a point. (IMG:style_emoticons/default/blink.gif) Seems over engineered to me. I will look at the various options once I cross that bridge. patssle did it with a simple aluminum bracket, maybe others have found other ways too. (IMG:style_emoticons/default/smile.gif)

[Chris914n6]

5/16 - 8mm is sufficient.

Looks like you've decided on the -6.

I run 225 on 7x16 on my 190hp 205tq 3L. Grip is sufficient most of the time and makes for nice right foot oversteer if desired. Though my Nissan swap is 374 lbs all in so it's a bit lighter, but what's 100 lbs on a 2000lb street car.

The -6 acc cable setup is meant for a carb'd car. I thought you were going to keep it FI?

[mb911]

Well I personally have never driven a big 4 so can’t comment on that. My 2.4 s piston, solex cam, mild port, EFI 6 is pretty fricken fast for what it is. It is plenty powerful, light in the corners, easily kick the back end out if you want to. When I added EFI it changed how I use the car and now it easy to drive daily and super fun. Big six is not my thing though what Clay has done would be on my radar if I wasn’t still raising kids that cost a small fortune.

To me the small six is the best bang for the buck

[gereed75]

I have a factory six with the stock accelerator linkage. Never liked it. After much adjustment and fiddling it works barely ok. It is necessary to get all of the lever angles just right or you loose travel. Then there seems to be a lot of friction in the thing even though all my bushings are correct and in good condition

If it weren’t for “keeping it original “ I think I would do the simpler direct cable.

[mepstein]

If you do a simple cable, you just have to make sure you can get full travel. I think the linkage is silly, adds failure points, friction, cost and flex but we usually just go with it on all the 911’s we work on because for whatever reason, that’s what Porsche did. If you decide to use a cable, I would coat it with light grease so water can’t build up in a low spot and corrode the cable and housing.

[Montreal914]

@Chris914n6 thank you for the info on the fuel line, that unknown (at my end) is now solved. No, I haven't decided yet to make the jump, but so far there are many pros in this option. No world is perfect though and both options have compromises. Although the big four basically doesn't add any weight, it becomes a "blown up" engine with all of what that entails, vs the stock reliable 911 engine, which is heavier. It obviously doesn't only boils down to this, it's just one of the pros/cons example.

Without having driven any 6 powerred 914 it is difficult for me to evaluate but my initial thought would be that 160-180 hp in a narrow body would be enough, especially with a lighter /4 engine. I don't think I would need more than that. @mb911 , yes over the years, even if I never though of converting my car to a six, I was always thinking the 3.0 would be the very top limit I would consider and that option would have been based on its known reliability.

Today, I have this oportunity of a 3.2, not neceesarily my first /6 size choice, but it is there. (IMG:style_emoticons/default/smile.gif)

@mepstein are you saying the cable travel produced by the pedal movement is less that the required movement to completely open up the TB? Is there actually a multiplying factor done by all of this elaborate 914-6 linkage? If so, that is a very different situation that requires some engineering consideration. (IMG:style_emoticons/default/idea.gif)

@gereed75 , comment noted, as with all of the shared ones.

Spent my entire day off yesterday reading on this. Again, loving all of the inputs provided (IMG:style_emoticons/default/smilie_pokal.gif)

[mepstein]

I think the linkage affects the ratio of pedal travel to throttle travel. I haven’t measured but on my own cars, I’d like to get rid of the “coat hanger”

Try to get in a 914-6. Like I mentioned previously, you can’t just compare HP between the engines. Just like a 911 drives differently than a 914, the engine impacts the character of the car. I wish the six engine wasn’t heavier but the way you can use the engine to drive the car can mitigate a lot of the issue.

A big four basically bolts in the same way the old engine comes out. A six requires work to every system to get it fitted and running and realistically $10-20k in additional parts to get it done. But it’s a fun journey if you decide to do it. It’s hard to beat the sound of a six.

[echocanyons]

I have a hot 3.2 wide body and my son has a hot 2.4/4 narrow body.
The best description of each:
the 4 cylinder is a ‘lightweight athletic sprinter’ its plenty fast and keeps up well with the 6 in the twisties. You can find the limits of this car, but tough to find them on twisty roads or normal conditions.
The six feels much heavier and probably due to the wider tires, feels like your ‘wrestling a bear’. It’s fast and the limits are really my comfort level in pushing it. It’s definitely a brute.
In conclusion the speed/power in the 4 cyl is surgical precision, while the 3.2 is mass destruction

I definitely wouldn’t swap my 6 for a 4 primarily for the thrills that you get while pushing your own limits and the car still having bogs to dish.