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Time to let the cat out of the bag


Timm

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4 hours ago, brian in buddina said:

tell us more Timm

OK here come the juicy details...

I was gonna do a proper write up last night, but I was just too tired.

 

To make this happen, here are the mods that I've done recently:

- VEMS pnp standalone ECU.

- Custom built turbocharger using k26/8 turbine housing, to4e centre and comp housing and new billet compressor wheel.

- Raceworks 1150cc injectors

-Bosch 044 fuel pump

-Turbosmart 45mm hyper gate wastegate

-Custom turbo intake pipe

-TTV Racing 60-2 lightweight flywheel

-KEP Stage 1 clutch pressure plate

-Sachs sport clutch disc

I should also mention that I rebuild the whole engine two years ago with some extra goodies that has provided a nice reliable base for the extra power.

-Cometic metal head gasket

-ARP headstuds

-Molnar rods

I first ran the VEMS with just the stock turbo and wastegate to see how it was. Overall the install and setup was quite easy. During the first drives I immediately noticed that all of the off boost driving had improved significantly. Unfortunately for me though, I was getting trigger errors and the car was misfiring above 5k rpm. Peep (the guy who makes vems for Porsches) was extremely helpful and we tried a lot of things to fix the issue, but in the end we concluded I needed a new trigger system. I considered going for a crank nose mounted trigger wheel, but finally decided on getting a new flywheel with 60-2 trigger teeth machined onto it. I was able to keep the stock sensor and sensor bracket, but it no longer reads the starter ring teeth, and instead has dedicated trigger teeth similar to what the S and S2 have from factory. Swapping out the flywheel wasn't a fun job...but I figured if I was to reach my power and torque goals I would have to upgrade the clutch anyway, so I did that too while I was in there. Anyway, with the new flywheel it revs cleanly all the way to redline, and the lighter weight makes throttle blips for rev matching a lot crisper and quicker.

Getting the turbocharger made also turned into a bit of an ordeal. I bought an old vitesse stage 2 turbo out of canada which needed a rebuild. It took 3 months to get here...then I sent it to a local turbo guy to rebuild and perform some upgrades, he did an ok job, but he sent it back to me with a broken turbine blade not once, but twice...so that dragged on for months as well. Now it has a random turbine wheel in there, from a tractor of all things, which is not as good as the lighter weight vitesse massaged one that was in there to begin with...oh well.

After I had finished all the mods it was finally time to get it tuned. I had fun tinkering around with vems getting the cold starts working and other small things, but I soon realised I was way out of my depth when it came to tuning. Luckily a good friend of my brother and I was willing to tune it, and boy has he done a great job. The guy has some real talent and I think without him I probably wouldn't have gotten anywhere near as good driveability and power as I do now.

For comparison here is a 'before' dyno from when I had the stock ecu (chipped) and k26/6 turbo, running on 15psi but bleeding off to 12ish psi as the rpm goes up. On a different dyno unfortunately, but you can see how radically different the performance is now.

VvdWg8T.jpg

 

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12 minutes ago, brian in buddina said:

good job Timm.

whats next?

Thanks Brian. Next immediate mod will be a larger, better intercooler. The engine will only make the 370hp at 40 degree or less intake air temps...after that it starts pulling timing thereby reducing power. At 60 degree IAT, power has already dropped to 340hp. The stock intercooler seems to be good enough for normal street driving, but I suspect that on a warm track day the IAT will climb above 40 degrees.

Other than that...E85 is on the cards. The car is ready for it, just needs an ethanol content sensor...and I should probably upgrade my CV joints before then.

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22 minutes ago, Peter M said:

Timm,

So you are you using stock pistons and cam?

Holy cow what a great result!

Thanks for posting the details.

Regards

Peter

 

Thanks!

Yes, I reused the stock (forged) pistons, albeit with new rings. I didn't have the budget for new pistons at the time when I built the engine. The cam is also stock.

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4 hours ago, Coastr said:

How much torque can the transmission handle?   You couldn’t put that through a 915

The Turbo and S2 transaxles can handle quite a lot of torque, but it also depends on other factors such as traction etc

I don't do any launches or 1st gear pulls so I think it will be ok. People have used the stock boxes with much higher power and torque than I have.

3 hours ago, 911B said:

where does one find a wonderful wife like that?

Haha, I was lucky to have a very supportive and understanding girlfriend at the time.

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Wow Timm, she is really coming along! Congrats on the latest round of mods. The power and torque figures are looking very healthy. You might crack 400hp with E85... ;)

How is your transient response below 3500rpm now?

I'm keen to take a gander at the next C&C if you're around.

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16 hours ago, Coastr said:

How much torque can the transmission handle?   You couldn’t put that through a 915

They commonly connect LS Chev engines to 944 Turbo transmissions - see Renegade Hybrids for examples.

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On 8/7/2018 at 9:52 PM, OzJustin said:

Wow Timm, she is really coming along! Congrats on the latest round of mods. The power and torque figures are looking very healthy. You might crack 400hp with E85... ;)

How is your transient response below 3500rpm now?

I'm keen to take a gander at the next C&C if you're around.

Thanks Justin, yep I'm very happy with it for now and yep 400 might be possible with the corn juice, though I mainly want it for cooler engine temps and more ignition timing down low to hopefully help spool the turbo a little earlier.  ?

Throttle response and general off boost driving has improved dramatically despite the turbo itself being a little bit laggier than the stock one. Even when I first put in just the VEMS by itself I noticed that it drove a lot nicer off boost, and now since it's been tuned it drives even better.

 

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