Turbo for a 914..., this may work Options

[mattillac]

Granted you can't make a type 4 like a twin turbo supra engine or nissan skyline, that isn't the point and only a fool would even contemplate such a concept.

what about a quad turbo, one for each cylinder (IMG:style_emoticons/default/monkeydance.gif) (IMG:style_emoticons/default/mueba.gif)

[Brett W]

Hmmm, I guess you've been reading different books than I have.
According to Bob Tomlinson in turbomania (a book about turbocharging air cooled flat 4 engines) he states that long duration is a negative because it allows some of the charge to go out the exhaust with no benefit. He says anything over 270 degrees is too much. Corky Bell agrees with that statement in principle. I can't say much more except I've BTDT with good results.

Can you provide some information to what you used to make the statements on the cam? Particularly higher duration and lobe centers as it applies to air cooled flat 4 engines. I'd be interested in reading that.

Have you driven a turbocharged 914 with a type 4 engine?

Others have done it with great sucess, they used the stock cams and had very boost happy motors.
If it works it works.
I'm a little confused at your statement that it takes too much to make a type 4 boost happy. Can you provide more details of what you think it takes?
Granted you can't make a type 4 like a twin turbo supra engine or nissan skyline, that isn't the point and only a fool would even contemplate such a concept.

I have read Tomlinson and Bell. Both are good authorities, too bad Tomlinson beleives heavily in that Draw through crap.

Duration is based on pressure ratio. IF you have a higher pressure in the exhaust than the intake then running long duration can cause intake charge dilution. In most cases the stock T4 engines when run with 4-6 psi will have a much higher exhaust pressure thus to much duration can be a bad thing but "too much" duration is realtive. The stock cam is cut on a 108 centerline, where most turbo cams will run 112-120+. Excessive overlap can result in poor running. The stock cam has something in the neighborhood of .242 lift with 192-210 deg @.020. Not enough duration for a good turbo cam, nor lift. Yes you can boost with the stock cam, that is not what I am saying. I am saying it is far from "optimized" for the boost situation. ON an aircooled motor running wide lobe centers tends to make the exhaust valves run very hot, not good on a motor that already has problems.

Never driven a turbo 914.

A type four is not an engine that is good for boost. The stock cooling system is pretty taxed in stock form, the heads are way to weak, thus the need for 5-6 stud arrangements, in addition to the shitty ports. In order to make it acceptable for boost it would take a major chunk of cash. It can be made into a really good NA motor.

If you want to boost your 914 go ahead. I have yet to see one that was done "right". I mean intercooled, standalone or programmable fuel injection , proper cooling system (not having the turbo up in the engine bay where all of the heat is preheating intake and cooling air), proper oil cooling to cope with the extra heat generated.

Ed's car was the closest but most people won't go to the trouble to do it all out. They want to throw a junkyard turbo kit on there and call it good.

[Jake Raby]

Sammy,
That book was written for the Type I engine...

Totally different animal, than the Type IV....

Very little of it pertains other than some genaral rules of Turbo charging...

The 270 duration rul is dependant upon boost levels and static CR.

I set up one Turbo TIV with 8.8:1 and 14 PSI.. The guy made 230ish HP with it on a chassis dyno!

BTW, Oil temps are just onme portion of engine temp.... A Turbo car without a head temp gauge is being driven very far on the edge...

[airsix]

If you want to boost your 914 go ahead. I have yet to see one that was done "right". I mean intercooled, standalone or programmable fuel injection , proper cooling system (not having the turbo up in the engine bay where all of the heat is preheating intake and cooling air), proper oil cooling to cope with the extra heat generated.

Well, um okay. Intercooled? Working on it. Ask again next spring. Standalone programable injection? Check. You forgot programable ignition for boost retard. Check. Not having the turbo in the cold side of the engine bay? Check. Extra oil cooling? Working on it. Cheap doesn't always mean poorly engineered or executed.

I'm not trying to fool anyone. I did not put together my turbo setup with the idea of it being able to run wide-open for extended periods. I need it to run wide-open exactly long enough to run a 2/3 mile autocross course, pass a semi, or spank a Honda. This fall I data-logged a 0-130mph run @85 degrees ambient and neither the head or oil temps got in the red. Would they if I'd driven another 30 miles at that speed? Sure they would. I doubt I'd have made it 10 miles at that speed before I cooked everything. It doesn't matter. That's not what I made it for. Could I put together a motor with nickies, big oil cooler, DTM or 911 cooling, special heads, & big intercooler? Sure I could. And then it would be a $6,000 project instead of a $675 project.

-Ben M.

[Brad Smith]

Speaking of "special heads..." What exactly IS available out there? The head is the weak link in the cooling system. I know that one of the aviation companies now makes water cooled heads for a Type I.

Which brings up another point- how 'bout a turbo waterboxer? (just a thought) I mean the VW one, not the scooby.

Ok, back to the point. Nickies are getting a good reputation with the aviation guys- but they still don't address head cooling. Yes, they will draw more heat out and dissipate more, but the areas that get hot would be the exhaust valve and exhaust port. Are there aftermarket heads that cool better? Also it seems I've heard of someone using Carrera heads- what's the deal with that? (Pricey, and I'm sure it would require some serious modification as well... but does it COOL better with those heads?) If you want a motor that can put out 150+ hp for an extended period, how do you cool it?

[iamchappy]

Dont get caught up in all the technical hype just turbo the damn thing and have a blast doing it and driving it.
I put a turbo on my 79 sc cis 3.0 engined 914 and got the same hype about this and that way to do it, I have no problems with my install runs cool, no predetonation, rich a/f under boost.
I certainly didnt build my engine to run at full boost all day long. Mine is a daily driver with a few spirted blasts now and then.
Like I said in my earlier posts, keep it simple.
And listen to the guys that have already done it.

[Jake Raby]

Special heads?? Like these?
http://www.aircooledtechnology.com/heads.htm
Those will be available in late 2005. Turbocharging will have a whole new meaning with these puppies, since they use a far superior exhaust port design- from a Type I!

The cooling issues are heavily dependant upon the engine combination as much as the cooling system.

I will tell you now that I have done ALL the R&D work on the Nickies cylinders and used more than anyone on this planet. These engines run super cool for many reasons including the fact that due to drastically reduced friction from the Nikisil that not as much heat is generated. The cylinders also act as huge heat sinks and actually suck the heat right out of the heads!

I have done back to back Nickies/ Cast iron testing on the same engine and saw drastic differences in temperatures, almost 75 degrees at full load for a 40 minute test at 4800 RPM. With the cast iron cylinders that test could not even be completed due to heat soak and what I'm sure would have ended up as a dead engine if I would have kept the throttle pinned.

Porsche knew what the limit was before the cylinders heat soaked and that was around 18HP per cylinder. This is why they went to aluminum, nikisil cylinders themselves. The cylinders make a huge difference after the throtle is held wide open and load is held steady. When testing with cast iron cylinders the head temps and cylinder temps will soar and never really level off with high HP (over the 18HP per cylinder rule) With the Nickies this is a different story, especially after the point where the cast cylinders heat soak. Here is a link from one Type I engine I tested so you can read about some results and some heat soak. This was not the worlds best test because I goofed up the combo and the engine lacked power to really see the nickies do their best. I never really got high enough on the HP chart to max out the cast iron cylinders with my cooling system on this one, but it is interesting. More tests like this have been done, but I have not had time to post the information to the site..

http://www.aircooledtechnology.com/r_d_2332.htm

Here is a link from my site from a customer that has a 201BHP N/A engine of mine. These temps are 50 degrees cooler than that of a STOCK 2.0 engine! Its a 2563 TIV...

http://www.aircooledtechnology.com/custome...llon/index.html

Also here is another from a customer with a 2739cc, 240 BHP N/A engine with Nickies in his beetle. His head temps run in the neighborhood of 25 degrees hotter than the 2563 link above. This engine has 10.3:1 CR and runs on pump gas.

http://www.aircooledtechnology.com/custome...testimonial.doc

Here is a link to my "Super Hero" page for the 914 crowd.... It has some more Nickies information there.
http://www.aircooledtechnology.com/type4/9...uper_heroes.htm

The other thing that both these engines have is my cooling system, which keeps all the cylinders very close in temperature compared to the stock arrangement. The 914 version of the cooling system is being developed as we speak.

5 words pertain here.
ITS ALL IN THE COMBO!

Trial and error is the only way to unlock these doors.

[Sammy]

LOL,
much of the same arguments against turbocharging came up around 4 or 5 years ago when I anounced to the internet world I was going to turbocharge my type 4 engine.
You can't control head temps, the cylinders and inadequate, the cooling system isn't up to it, you can't put the turbo in the engine compartment (insulation works very well in that application) etc. Good thing I and others didn't pay attention to it then, we would have given up on the idea instead of following through and actually making it work (IMG:style_emoticons/default/wink.gif)

That is where the saying came from, "YOU CAN'T TURBOCHARGE A 914".
I still get a kick out of hearing that.

I agree that there are serious design limitations on a type 4 engine. that is why most folks agree that around 6 ot 7 psi is the safe limit unless you can do an efficient intercooler, then you can bump it up a little.
Running around 12 to 1 A/F ratio under boost does wonders to reduce combustion temperatures. Sure that uses extra fuel and costs efficiency and is in a way a band aid, but it works.

If increasing the horsepower and torque of a type 4 engine by 50 or 75% or more isn't worth it, so be it.
It was worth it to me and like others here I did not spend very much money on it at all.
Getting an extra 60 or 80 hp out of a 2 liter for $500 seems pretty attractive to lots of folks here.
I could have spend a fortune, but that was not the plan or intention.
With an unlimited budget of time and money I could build a 400 hp engine that resembles a type 4 and that would last for many, many years.
That isn't the point.
While some 914 owners think that spending 10 times what the car is worth to fix it up makes sense, most don't. Most of us are cost concious and part of the fun of owning a 914 is trying to fix them up without having to get a second mortgage.

If I had $25k to put into a sportscar it would not be a 914, it would be a used Honda S2000.

[Jake Raby]

Most are just cheap asses period, thats why I have't really been developing any new 914 specific stuff for a while. I was very reserved when I started on the design for the 914 DTM because of this and had to get a bulk of interest before I started doing it...

My best customers are VW guys. They spend the most money and want the most performance from what I do..... Isn't that funny as hell??? Alot of them never even ask how much it costs until we do a proposal and they never question the money...

The 914 crowd generally is 100% opposite, they ask about price in the first email and try to cut any corner they can to save a buck!

This just started happening about 3 years ago, the 914 work fell off and the VW work took over.

I'm cheap too. I build all my own engines out of junk from other blown stuff and screw ups on the dyno.. But my labor is free and tools/equipment are a write off and that makes a big difference..

[JmuRiz]

Yep, just like those. I can't wait to see the numbers (HP and flow) on these puppies, I've been waiting over a year for them. I've been saving my pennies and waiting to do any engine work till I see the numbers on these. Did I mention I can't wait.
I think if you did a turbo you'd need heads that flows really well, some nickies to better seal and dissipate heat, and a trick FI setup to make it REALLY work. If you were running a lot of boost an intercooler would be needed but not if you are running low boost. Then again I'm just an armchair QB.

[andys]

Well, I have to say I agree with some of the previous comments regarding "drive a 6psi boosted 914" before you draw any conclusions. It really is a decent power package that transforms the stock 914 quite nicely. Configure to what you have, rather than trying to force more out of it then can be had, IMO. If you think you want more than that kind of performance, then you must be prepared to take it to an entirely different level. That level however, I'm not convinced is a very resonable vision given the foundation from which you will have to work from. If you just have to have more power, then perhaps a modern turbo four, six or V8 is in your future.

I learned about turbo's the hard way. Very little printed matter was available in the late '60's on turbochaging, so we (I) though hard about what we were trying to accomplish. I was fortunate enough to befriend an engineer at Air Research who perhaps took pitty on a young guy with dreams. We designed nearly everything, and did a lot of fabrication and adaption. The wrong decisions were quickly evident, broke some stuff, but learned a hell of a lot. I know all that stuff was old school compared to what has evolved since, and what is available today. (And) I do not profess to be current any most of it, especially the electronic controls. The fundaments however, haven't changed.

Andy

[Jake Raby]

The trick with Turbo is a nice flowing exhaust port. This geats plenty of heat and pressure into the Turbo and that decreases lag and makes more power.

My big heads should be great for Turbo with the right port margins.