Rob_B

Hey Chris, did you ever get a chance to get your car on a dyno? The quick spool-up time and strong mid-range torque you've mentioned are exactly what I'm looking for for my street car. I've talked to Charlie a couple times now and plan on going the same route you have, but figured I'd ask if you have any dyno graphs. Are you still running it at 0.7 bar of boost or did you bump it up to 1.0 bar? If you did, how's the VEMS boost control? And how do you like VEMS overall? I need to contact Peep cause I'm definitely intrigued. Also, have you been experimenting with different intakes or are you still using the stock airbox setup?

Sorry for so many questions!
Thanks, Rob

Sidenote, I'm pretty sure I saw your car in a PCA autocross event at Earl Warren Showgrounds maybe 7-ish years ago? If that was you then you were definitely one of the fastest from what I recall!

Droops83

Hi Rob,

No dice on the dyno nor the intake testing thus far----too many damn car projects, not enough free time! But this will hopefully happen in the next month or two. I'm a bit worried about high EGTs during track use due to the small #6 turbine housing, so EGT vs back pressure will also be data-logged when I get a chance (the VEMS has a couple of spare analog input channels). I was running ~1.3 bar/19 PSI during the first half of the Coastal Range Rally North a few months ago (extremely fun event, should do a belated post about it), but my stock ignition coil was not keeping up and the engine started missing under heavy load. Turned the boost down to 0.75 bar/11 PSI to be safe and it was great for the remainder of the trip, and more than enough for the tight and twisty mountain roads of far northern CA. I have a wasted spark ignition system from Peep on the shelf, to be installed at the same time as some of the other sensors/wiring mentioned above.

I really like the VEMS overall, it is pretty straightforward to set up and tune once you wrap your head around the standalone thing. The electronic boost control works well once configured properly, boost hits hard! Here is a link to the current ongoing thread about VEMS installation and setup:

https://rennlist.com/forums/944-turb...s-install.html

I strongly recommend that anyone looking to go down the standalone path should take at least the basic HP Academy tuning courses. Really good information presented in a logical and understandable manner (this is coming from a professional Porsche technician):

https://www.hpacademy.com

My best advice is to make 100% sure there are no vacuum leaks and/or other underlying sensor/wiring issues before (and after) installing such a system.

And yes, I remember sliding around on the gravelly surface of Earl Warren Showgrounds years ago, it was pretty fun! But we were tearing up the parking lot and they stopped letting us do auto-X events there.

74goldtarga

I have a K27/8 from Evergreen that has been a very good turbo with my 2.5 and now with my 3.0. Charlie is very knowledgable and seems to do good work.

Rob_B

I know how you feel! Too many projects, too little time. You should definitely make a post about that rally; you made me do some Googling and now I'm intrigued!

Interesting, yeah for my usage on the street running around 10-12 lbs. on the #6 hotside sounds perfect, but I can see how for the track the #8 hotside would be better. That will be great to see the EGT vs back pressure plots for the #6.

Thanks for the links! I'm definitely going to take your advice and do as much learning as I can beforehand. And fortunately I helped my brother a little bit with building and tuning his MegaSquirt for his turbo E30, so I'm at least mildly familiar with standalone ECU systems.

When I bought my car it ran well and had just passed smog, but the timing belt gave up the ghost on the drive home, so now I'm in the middle of a full rebuild. It would be nice to put everything back together stock for the first startup and for breaking it in (I don't really want to add any more variables to this equation), but at the same time I'd prefer to upgrade the turbo while the engine's out of the car. Do you think it's unwise to install a K27/6 and VEMS on a fresh engine build? I want to break in the engine/seat the rings properly, but that might be difficult if I initially can't get it to run right. Or am I worrying about it too much? I'm not new to 944's and this type of work in general, but I don't want to make a brash decision.

Hah, I do recall everyone working the cones staying quite busy. I was wondering why you guys stopped, that's a shame!

Sorry, I didn't mean to hijack your thread! I have a few more questions about your car; is it okay to ask them here or is there a better place? Thanks

Droops83

You could start your own build thread here to share your experiences with others, and get feedback from other members. I understand your hesitation to start up and break engine with VEMS and other upgrades installed; the last thing you want to do is wash down your cylinder walls with an excessively rich mixture or damage something due to a lean mixture! If your rebuilt engine will be a near-stock 2.5L, I could send you my VEMS config file, which will likely get you in the ballpark in addition to some auto-tune drives.

For initial engine break-in, you definitely want to put the engine/rings under load, but you also don't want too much boost pressure. If your waste gate has a lightweight spring, configure it to run off spring pressure only (vent upper chamber to atmosphere) to keep the boost down and keep pressure from building too quickly. When we break in engines at my shop, we drive up and down the San Marcos Pass/Highway 154, which provides good, consistent load on the way up and lots of deceleration/engine braking on the way down.

Good luck with your project.

Rob_B

Starting a build thread sounds good. You don't happen to have a build thread yourself by any chance, do you?

That would be great to be able to start with your tune, thank you! In that case I'll plan on matching your intake tract, fuel delivery and exhaust systems as much as possible. What my build will lack in originality will hopefully be made up for by predictability and cross check-ability!

Thanks for the advice on the wastegate and the suggestion of breaking in the engine on the pass. Funnily enough the 154 is where I got stranded when the timing belt stripped so hopefully the next drive up there with this car goes a little better! Thanks again Chris.

dga

Hello, I just sent my 26-6 to Everygreen to become a 27-6. I am excited!

In the first post in this sequence, Droops83 indicated he/she installed a short temp sensor...is this necessary for clearance reasons? Which sensor and where did you get it from? If I need it, I need to order ASAP in order to have it for the weekend when it all comes together!

dga

I called NAPA and the temp switch FS158 will take a while to get here, and costs $50

On Autozone.com I found:

https://www.autozone.com/engine-mana..._173413_0_5835

which costs $20, gets here tomorrow, and thread is M14x1.5, and the thing is quite short...

good?

Droops83

As long as the temperature range is near that of the stock switch (I think 105-110 degrees C) and you are sure that is a SWITCH and not a SENDER, it looks like it should work (I accidentally ordered a sender at first, which always had continuity to ground and ran the auxiliary water pump continuously unless it was unplugged).

dga

I have the temperature switch in hand. The one in the car, presumably stock, has written on it 118C (+/-3C), so I guess that is the switch temperature. For the one I got, I cannot find a temperature setting on it, nor via Google.

However, it is a Duralast TU151, which is also a FAE 31290 (written on the temp switch), and online tells me it is same as BMW 62110788115. It seems the FAE 31290 is used in over 65 cars, most of them BMW. I paid $20. I see prices <$5 elsewhere. Oh well. It is M14x1.15 thread and it matches well with the stock though it is much shorter. Have not put back together yet, but should be good

dga

Help! Got my K27 on Saturday for my 1986 944 Turbo. Took effort but finally got it mostly back together, but I have the following two problems:

1. Water line to the thermostat and then to the banjo bolt to the Turbo is problematic: I can turn it a bit so it can be tightened but then the thermostat, even the super short one I got, hits the manifold. See attached pic.
2. By the air-intake of the manifold, near the throttle position sensor, there is a vacuum line input underneath -- it hits the K27! and thus cannot seat the manifold correctly. What can I do here? I think I see one hole in front of the throttle plate which might be the vacuum line input...can I cut off vacuum mine input and relocate it and make a hole etc. Not sure how to make shorter as is...I think I might need only 0.5 cms less.

Droops83: what did you do!!!???


vacuum line metal connection under air intake hits K27 .... what to do?

how can I extend/change angle of the banjo bolt for water connection?

how can I extend/chang angle of the banjo bolt for water connection
55555555

shortyboy

Very well documented issues. For the water pipe, you can either add a few brass fittings to extend the length or heat up the pipe and bend it slightly ( be careful as it can crack ). For the vacuum nipple, you can either grind a bit off the bottom of the nipple or grind a bit off the turbo housing. using double intake gaskets also works well. Search the forum, lots of info and pics.

dga

Super! Do you know the thread-size for the extension/nipple for the thermostat-to-K27 connection?

Droops83

I bent the coolant pipe and bracket as shown, and added a brass extension to the hose from the expansion tank. I remember that vacuum fitting at the bottom of the throttle body being close, but I did not run into any issues with that. I can take a pic of that later if you want.

968to986