Project Turbo 914 begins..., (yes, I know you can't turbo a 914) Options

[ottox914]

Posting a little update- surge was really not what I thought- had a leak at the gasket between the intake and head. The car is/was LOUD, so much so that at our last autocross, (and keep in mind I'm on the board...) I was kicked off the grid for sound violations!!!!! In the 1st session I was at 95.5db at WOT in 2nd gear. 95 is the limit. In the 2nd session I took it easy runs 1 and 2, and I let'r buck for run 3. oooops, 97db on that one, and I'm done for the day.

So here is the solution:

OLD: http://www.youtube.com/watch?v=rGoTFrCu97k
(Car was just started and not warmed up yet.)

NEW: http://www.youtube.com/watch?v=1qV436Ydm_U
(Car was well warmed up...)

No surprise, the new system is more restrictive than the old, and the boost comes on slower and is a psi or 2 less than before. But. I have 12 more discs and an endcap with a 2" hole in it to try on event days, to see how close to 95db I'll end up with a freer flowing system. I can always pull some discs or put the solid end cap back on for the ride home.

[Root_Werks]

Sounds good!

This would be a 914 I'd love to see in action.

(IMG:style_emoticons/default/driving.gif)

[Andyrew]

I personally dont like supertraps... But with that turbo location your kinda SOL...

[Woody]

So how did this turn out? I am very intrigued.

[ottox914]

I suspect it will never be "done". Was chasing boost leaks last fall when winter came to WI. As the snow is going and garage temps raising, I should be back at it with a winters worth of ideas to try.

Updates will be posted as progress would warrant.

[Walter]

I suspect it will never be "done". Was chasing boost leaks last fall when winter came to WI. As the snow is going and garage temps raising, I should be back at it with a winters worth of ideas to try.

Updates will be posted as progress would warrant.

Any warrents for updates yet? (IMG:style_emoticons/default/biggrin.gif)

[rick 918-S]

(IMG:style_emoticons/default/popcorn[1].gif)

[r_towle]

couple of questions.

How did you address potential head/cylinder leaks?
Did you do anything special to the heads or the tops of the cylinders?
I did not see anything unique there.

Also,
What HP are you predicting at this point?

Rich

[ottox914]

Got a few PM's lately on project status, and holy cow- its been awhile! Sorry guys.

First of all, overview of 2012. I got a tough hand of cards in 2012.

Started in 12-2011. Lost my job of 8 yrs, after 20+ in the industry. Oddly enough I was the most tenured and highest paid of myself and my co-workers. Hmmmm... In March scored a position in a related field. This co. stated out front they had no real training program but they thought I'd do just fine. After exactly 90 days I was let go, and the blond at the desk next to me, with no more experience than I had, got my desk. Hmmmm... Was on UE till the end of the year, looking hard to replace a 60K job in my little town of 8000 people. Didn't find it. Thankfully my wife and I were smart with our $$$ when we had some, and the bottom didn't drop out of our world. UE ran out 12-12, and i took a job managing a small auto shop. That pays exactly the same as UE did- except that there are health benefits that are affordable. The COBRA we spent most of the year on was just under 1k/mo for health insurance. OUCH.

SO- bottom line, there wasn't much motivation or money to take the 914T up another level.

Time spent: Spent 2012 trying to get the small turbo to work. On paper, the 9B turbo should have been a perfect match to the 1.8 turbo motor. I have learned that "on paper" and "real world" are 2 very different things. I pulled the 9B and put the wrx turbo back on. Better results. Rebuilt the 9B and put it back on. Less better results. Seems something is up with how that turbo works with my overall system. I don't know if it is the turbo location, the 2 valve heads vs the 4 valve heads of more modern engines, volume of the intake system, or what. But. For whatever reason, the 9B wouldn't build much more than 5-6 psi, and all this would be from 5-7k rpm. So not much low end, which is what I was going for with the smaller turbo. So the 9B is out. So much of 2012 was turbo swapping, which costs zero dollars, since I already had both turbos. End of the driving season I was taking the car out for a little October beat'n run, and the boost went away and the car ran but poorly. Got it back home and checked things out. The old, dirty air cleaner had collapsed in on itself, and was stopping the turbo from spinning. So more $$$ to spend on a cheep air filter, so I could get it running and into storage. The air cleaner I found was about 2x as big as the one that failed.

WINNER!!!!!!! With 2x as much air getting in, the turbo woke up. With the engine spinning to 7k, I'll see 13psi at the top of 2nd and 3rd gears. Fun. The car revs much more freely, boost and speed build much faster. Where before the car just felt like a bigger NA motor, with smooth power building across the rpm band, it now had a noticeable p u s h back into the seat from 4k to redline. Over and over again. Sadly all this fun happened on the drive to storage.

Money spent: Spent a small amount of real money to have an exhaust shop modify the supertrap to have it fit much better with the wrx turbo, since that is the one we're going with. It looks much better, and is much quieter at an autox. Most I blew was an 86db, which is well under the 90db limit at most of our sites. There was also a set of new/never used star spec tires I picked up over the winter from a chump car team that had moved onto a different car. They were only 195's, but $300 for a basically new set 4 tires was a deal I couldn't pass up, as the existing tires were 5+ yrs old and hard as rocks. The big cost was the elephant bushings for the rear trailing arms. I had an odd "click" in the rt rear for a yr or so, and the handling was getting odder and more weird at the autocross. I was thinking it was a bad shock, but traced it to the trailing arm bushing. So this spring I have a big project, to remove the trailing arms, power coat, replace bushings and bearings, and get it back on the road.

Autocross: Made enough events in 2 separate series to win my class in both. Even with goofy handling of the "variable random toe" provided by the trailing arm bushing wear. So with a more buttoned down suspension and more boost, the car should be even more potent next season. And if I can find better work and some Rcomp budget...

Things I love about this project. Off the line it feels like any strong type IV. And then. The torque when the turbo starts pulling is amazing. I'd love the tq to come on sooner, but we'll see how things develop. The engine and turbo pull like crazy right to the fuel cut at 7k. Having the tq come on in the mid-upper end is probably thermally less taxing on the motor. It looks basically stock but for the panasports. AND, I CAN"T say enough about Len Hoffman's heads. I'm sure the cam from Jake has plenty to do with this as well, but the new motor runs SO cool. Engine temps are right where they were expected and rock solid. EGT, CHT, oil temps and pressures, I couldn't be happier with how stable and steady these have been. If I were track lapping the car it might be a different story, but for back road zipping around and the weekend of autox, perfect.

2013: I'd like to try another turbo. Really? Really. I've been thinking of a Ko3 as would be found on our Audi TT. Thats a smaller turbo, seems to perform well on the 1.8L TT motor. They were out there on all manner of 1.8T motor from Audi and VW, so there may be some used options cheep. Get those trailing arms re-done. If I choose not to try yet another turbo, some dyno time for sure. I'm as curious as the rest of the world to know what it puts out. I'd like to pull the OEM mufffler heat shield and re-do the air cleaner to pull it up and away from so much road grit. And find a better paying job so I can afford more goodies for the 914T.

I should be out to the farm this weekend, I'll try to snap a couple pics of the new muffler and air cleaner set ups.

[ottox914]

couple of questions.

How did you address potential head/cylinder leaks?
Did you do anything special to the heads or the tops of the cylinders?
I did not see anything unique there.

Also,
What HP are you predicting at this point?

Rich

Bad on me for taking so long, but the prior post is the story of 2012.

Nothing special on the heads/cylinder junction. Other than the wisdom of Len Hoffman. His suggestion was that he isn't really in favor of turbo type IV motors for just this reason. That junction is a potential problem area. His thoughts were that as I was building a budget motor here, lets use the 1.7 cyls as they have thicker walls, and therefore a thicker/wider sealing surface to the head. I got the cyls and heads to Len so he could check and be sure all the mating surfaces were going to be happy together. On my little motor, shooting for no more than 1bar boost, he thought this would be fine enough. If you were going for some larger cyl size, or crazy higher boost, there maybe other steps to take. And if you were paying to play at that level, you probably can and should take greater steps to preserve your investment.

As for HP. Anyones guess. I've only driven stock cars of all 3 engine sizes, and a 1600lb 200+hp autocross beast. My street car is somewhere in the middle. I'd like to guess 150+ or so at the wheels, but who knows how accurate the owners butt dyno really is. I really need to stop messing around here, tune the SDS to the turbo thats working, and see where we're at.

[Andyrew]

2013: I'd like to try another turbo. Really? Really. I've been thinking of a Ko3 as would be found on our Audi TT. Thats a smaller turbo, seems to perform well on the 1.8L TT motor. They were out there on all manner of 1.8T motor from Audi and VW, so there may be some used options cheep.

What turbo do you have now? Where do you see full boost and how much PSI do you run?

I am a turbo guy, my Audi 1.8T's KO3 I replaced with a GT28R, which I replaced with a Comp Turbo CTB5356.
The KO3 is to small of a turbo for even just the 1.8t, Full boost under 2k, Boost starts to taper off after 5k, Shift at 5.5k Max power ~ 160AWHP (20psi).
The GT28R was a perfect sized turbo for the 1.8T as an autox'er or daily, Full boost under 2500, boost doesnt taper off even at 7200rpms shift at 7200 rpm's every time, max power 275AWHP(20psi)(This turbo gave INSTANT full boost above 4krpm's, aka any situation in an autox.).
The CTB5356 is a bit large, but with the increase in turbo technology its a very good sized turbo for daily driving, however a tad laggy for instant boost at autox. I would consider this an awesome track turbo. This turbo is designed to run extremely high boost pressures (35PSI) and still be efficient, which was the reason why I chose it. I run only 10psi at the moment and it makes the same power as the GT28R when I ran 20psi. Full (Low) boost ~4krpm, probably 4500 at high boost, boost probably wont taper off till 8500 rpms but my tune doesnt go past 7200 currently. I anticipate well over 400AWHP(25psi) when I crank the boost up. If I ran C16 and spent some time on the head I might see 500AWHP(35psi), but I dont think I'll get to that point any time soon.


I am a big fan of the right sized turbo for the job. You might want to look at the SR20DET turbo's that come stock. Some of them are ball bearing, but most are journal bearing and can be had CHEAP.

Small turbo's make excess heat. Excess heat means detonation. Get yourself a nicely sized turbo. I wouldnt throw a KO3 on anything more than a 1L Geo engine.

Also Audi TT's (225hp model) used a KO4, the 180hp model used a KO3. The KO3 has stopped being used in most engines due to its small size, the KO4 is almost the exact same size but is more efficient, however more desirable. Consider that if you REALLY need to go with a small turbo.

[ottox914]

http://www.914world.com/bbs2/index.php?sho...lutch&st=20

In my review of 2012 I don't know how I forgot the crazy clutch adventure.

Andyrew- thanks for your input on turbos. Yes, I agree, the right tool/turbo for the job, and I agree, smaller can = more heat. The intercooler set up I have, while unconventional, shows no more than 25-30 degrees above ambient temps for IAT, and for the short duration of an autox, I'm fine with that. I could always add water injection if needed, or go to an air-water set up. I've had experience with both.

The thing that is most vexing here for me is the airflow thru the engine. Even with Lens great heads and Jakes much upgraded cam, there just doesn't seem to be alot of flow to work with. I think its a combo of the 2 valve heads vs the 4 and 5 valve heads of more modern cars, along with the length of the exhaust system. STS with their rear mount turbos makes it work with a much smaller turbo than conventional wisdom would suggest. So what works better on your 1.8 5 valve TT head may likely be all wrong for my 1.8 2 valve rear mount turbo system.

For me a bunch of the fun is in the tinkering. So I may be looking for a good K03 or K04 to play with some more.

[tscrihfield]

The K03 and k04 are great little turbos! The only issue is their hot to cold side sizing. This would be my only disagreement with Andy. The K03 was optimized for the 1.8 due to the unsquare engine design. Reason being they needed torque out of a smaller displacement. You have an 80mm bore and 86mm stroke. This means you need a little volume of air really fast without huge boost numbers. Granted, this turbo will not last long when ran hard, but the way it was designed it will be reliable. This turbo will produce 12-18 lbs paired with similar volume (meaning exhaust gas CFM to intake volume). The way you Would ultimately pair a turbo would be based not only on efficiency of displacement to turbo but also volume needed (volume of cylinders/intake) to volume produced (cold side) to volume created (after engine firing headed to hot side). There are better ways of wording it but this gets my point across.

My graduation project for my high performance class was building two NA engines (2.0zetec, 2.4ecotec) with turbos. I ran a number of tests to optimize stock (junkyard) engines & parts. I was very lucky to have a teacher who was very well versed in the forced induction world and willing to teach a punk a$$ kid like me.

To sum up, all of the type 4s are that the opposite of what a normal turbo engine "would" be. We are dealing with large bores and short strokes. So with this said you would ultimately want to find a turbo that matches this "backward" design just the same. The volume of air coming out of the type 4 in exhaust gas is low pressure and in short spurts in comparison to a typical turbo engine by design. So increase the size of the hot side by trim not by housing volume. This will allow more movement of the turbo earlier to maximiize the low end, but the waste gate will be working OT in the upper rpm to bleed off the unwanted pressure. But let's be honest, we aren't revving these little guys to 7-8 rpm under boost.

I know it is a lot of information, but I have been through this and I agree that tinkering is an absolute blast!

Ottox I have a 13b turbo that has been rebuilt with a little shaft play but very usable if you'd like to try it, I think it would be a great match for you. I have really enjoyed your thread and I admire your work. Hope to see this car one day!

[ottox914]

Better late than never? I finally got out to my father in laws farm for a few pics of the current supertrap muffler set up. I know its not as free flowing as the straight pipe was, but it seems to flow pretty well just the same, as it is basically a straight thru system. And the small reduction in sound is appreciated. At WOT in 2nd gear I've blown high 80's db at an autocross, and with some of our sites at a 94 or 96 db limit, I'm right where I need to be.

Andyrew: Good to know about your positive experience with the GT28r on the TT. If/when the turbo on my TT pops I know which direction to go now.

tscrihfield: I've wondered about something just like this, as I have been puzzling thru the project. In all the books I read researching this, and later internet surfing, I don't recall running into a discussion of the bore/stroke being a consideration in turbo sizing. Maybe I just missed it, but what you said is just about exactly what has been nagging at the back of my mind for a couple yrs now. So accepting your position that the b/s configuration of the motor will have a direct effect on the onset of boost for a given turbo, all other things considered equal, what would your opinion be of a correct turbo for my engine, a 1.85L 4 cyl with a b/s of: 90/71, and why. And if you would, get into more of the specs of the turbo you have on hand, what cars it was on, and why its a better choice for my engine. Oh, and would the K03/4 be a decent choice according to your thoughts. Funny, I always thought of the 1.7/1.8 motors with the 66 crank as the "short stroke" motors, and now it seems my "stroker 2.0" 71 crank really isn't all that long... My "small" turbo was a 9b, one of the 2 turbos on a mitzu 3000GT. The turbo that is on the car now is from a subi 2.0L wrx. It seems to make good power from mid to high rpms, once there is some airflow, but I wouldn't mind the onset to be a little sooner.

Fun stuff! Thanks for adding your info to the thread.

[McMark]

Haven't run it yet... (IMG:style_emoticons/default/dry.gif)

But mine is a K03. There is a K04 that I should be able to jump to if this thing is too small, but I think we had the same thought process, "If it's on the small side for a modern 1.8 with modern CAD optimized flow, it might just work great for an old design Type 4." Mine is a tired, stock 1.7 though, so where your engine may slightly overwhelm the K03, I'm hoping my low flow engine will be perfect.

Who knows! One way to find out...

[Andyrew]

Mark is that an OEM ko3 or a Chinese version?

If its chinese, just realize spool with not be as quick as it should be. Be sure to run oil though it without firing the engine (aka remove the plugs and keep cranking, let starter cool and do it again...)

[Mike Bellis]

Mark is that an OEM ko3 or a Chinese version?

If its chinese, just realize spool with not be as quick as it should be. Be sure to run oil though it without firing the engine (aka remove the plugs and keep cranking, let starter cool and do it again...)

He has a real KKK K03... Ask me how I know... The one pictured is not it...

[mittelmotor]

Fun thread, ottox! I noticed your Direzza Star Specs in the photo...one of my favorite tires. (IMG:style_emoticons/default/piratenanner.gif)

[Justinp71]

couple of questions.

How did you address potential head/cylinder leaks?
Did you do anything special to the heads or the tops of the cylinders?
I did not see anything unique there.

Also,
What HP are you predicting at this point?

Rich

Is the T4 much different than the T1 at the cyl/head mating? I did a turbo on my T1 and put some of the soft copper shims to lower the compression and figured it would get a better seal. No problems and those engines get turbo'd alot.

[tscrihfield]

tscrihfield: I've wondered about something just like this, as I have been puzzling thru the project. In all the books I read researching this, and later internet surfing, I don't recall running into a discussion of the bore/stroke being a consideration in turbo sizing. Maybe I just missed it, but what you said is just about exactly what has been nagging at the back of my mind for a couple yrs now. So accepting your position that the b/s configuration of the motor will have a direct effect on the onset of boost for a given turbo, all other things considered equal, what would your opinion be of a correct turbo for my engine, a 1.85L 4 cyl with a b/s of: 90/71, and why. And if you would, get into more of the specs of the turbo you have on hand, what cars it was on, and why its a better choice for my engine. Oh, and would the K03/4 be a decent choice according to your thoughts. Funny, I always thought of the 1.7/1.8 motors with the 66 crank as the "short stroke" motors, and now it seems my "stroker 2.0" 71 crank really isn't all that long... My "small" turbo was a 9b, one of the 2 turbos on a mitzu 3000GT. The turbo that is on the car now is from a subi 2.0L wrx. It seems to make good power from mid to high rpms, once there is some airflow, but I wouldn't mind the onset to be a little sooner.

Hey Mark,
I have a question before I delve too deep into opinions. Have you ever had the heads flowed? Knowing the CFM on the exhaust runners helps but not necessary.

I have played with a few Numbers to calculate what I think might help. That engine is capable of moving somewhere in the neighborhood of 430 CFM max. This is assuming your heads flow at 1:1 rate with ability of volume able to move and have no restrictions in your intake/exhaust. The one big issue with this assumption is pressure will have to go somewhere if it does not exit through the exhaust. if it cannot go out the exhaust smoothly it will escape during the valve overlap period therefore pressurizing the intake while the turbo is trying to feed pressure in. This will cause what is known as compressor bind. If it is not audible it is a bear to hunt down and a lot of folks never know they have this issue when they have it.

I want to also state that the cam plays a part as well. But I will leave this out for lack of more overload.

Now we are still playing with a vacuum pump but the information I have gathered is this (and this is my theory behind the B/S difference). When I refer to this difference it is in leiu of the typical person trying to size the turbo. The only time you have a greater amount of CFM ability loss is when your bore exceeds stroke and this is what throws off so many folks CFM predictions (your simply dealing with a different beast). I don't have all of the answers behind it but my guess is that it has to do with common physics. Larger volumes of air are trying to exit the cylinder at the same time whereas a smaller bores with larger stroke has smaller volumes of air exiting the cylinder at that moment in time. If I was hosting a webinar this would be easier to demonstrate because I lack at conveying messages by form of writing. Non-the-less I hope you get it.

I would stick with a turbo that moves less CFM through the housing than your engine produces, remember you can always bleed of anything you don't need. This will allow the spool to happen quicker and peak faster. The one downside is heat. Now the good thing about this is you can go with a smaller housing with the same trim and see huge improvements with your current setup. The current turbo you are running is known as the TD04-13T. The turbo I have is the TD04-13G the biggest difference is Volute size which directly changes CFM flow. The 13T is rated at 385-400CFM and the 13G is rated at 345-360 CFM. it is originally off of 1G eclipses. My advice in any application with these cars is to run an external waste gate so you can get proper boost and bleed off the heat. But for both of these turbos you can get away with the stock waste gate built in the turbo and be fine, just don't crank them too high.

On the K03 it will actually flow less than the 13G and the 9b would be about the same. the K04 will flow about the same as your current turbo. I do agree with Andy on the SR20 turbos. Stay away from the base T25 turbos they are looking for too much volume and their journal bearings suck. The later 90's T28 had ball bearing but still a .80AR and 60 trim. This would spool a little later than the 13G and sooner than your current turbo but peak quicker than any above mentioned.

Please feel free to ask me anything on this. Most will be dialing in to find what the engine likes. I love this thread and it looks like you are on the right track!

Thomas