I had the pleasure today to watch as Bill Hahn Jr. and his son Adam took their new 2006 Cobalt SS 2.4L turbo car to the track for the first time. They got started right away, doing their first run as soon as they got checked in by tech. Adam was driving the Cobalt, while Bill was driving a brand new, basically stock Solstice GXP with the new LNF engine. They ran side by side, and the first numbers where very promising.



That's a 14.0 for the Cobalts first try ever! And on stock tires!



Back in the pits, I got my first real good look at the Hahn customized Garrett turbo kit. Of course my greatest interest was in the fuel system, and here is what I learned.



The system was converted to a return-style system using little more than a BoostFueler and the necessary plumbing as highlighted above. Air to Fuel ratio was adjusted with a simple turn of the knob.



AFR's where the concern of the night. Data logging was done with each run, and small adjustments made each time. The first recorded run held very steady at a rich 11.2. However, there was near zero variation. The ratio held perfectly steady. And with a small adjustment to the BoostFueler, the ratio leaned up to better numbers as the night went on.

Some other items I looked at was the oil return design. Hahn sends the oil back to the pan via the stock drain plug, which returns the oil below the level in the pan. To avoid air pressure problems that would be associated with that, the drain is vented to the case via a line attached to the water pump access plate as seen below.



There was no mystery to the manifold pressure plumbing. The line was tapped right below the throttle body, and tee'd off to the various systems, including the waste gate, blow off valve, BoostFueler, and boost gauge.



The biggest challenge of the evening was getting the car into the 13's. After that first 14.0 run, it instantly became the goal of the night. But it was proving hard to get. After that first run, Adam kept hitting 14.2's each run after that. It lead to many conversations in the pits.



We discussed the Automatic Launching technique for the Cobalt that I wrote about here. Adam tried both that technique, and simply launching from "Drive". He decided the launching from "L" technique was best. But that alone still didn't make it happen. He dropped his tire pressure a few PSI each time, but that wasn't doing it either. Then on the final run, Bill suggested Adam burnout the tires considerably hard. The track didn't want people with street tires doing burn-outs, but they let it slide. That was the ticket. The car hooked, and it hit 13.7!



I had a blast. It was fun to watch Bill get so excited with the results. Some additional notes about the car itself...

It was completely stock except for the turbo of course, and a Hahn cat-back exhaust. By the way, the whole system, turbo and exhaust, was VERY quiet. You couldn't tell standing next to it that anything was different about it from a stock car. Absolutely zero rasp from the exhaust.

The blow-off valve is plumbed back to the intake, so there is no blow-off noise. The valve appeared to work just fine, however it was a tiny plastic part. If you wanted to do anything with different boost levels or vent the blow off to the atmosphere, you would need an aftermarket valve.

The BoostFueler that Hahn was using was mounted to the plastic ECM cover. That didn't seem like a very good spot, especially since that cover just sits loosely over the ECM. A better mounting location might be a good idea.

The stock fuel pump is retained. However, I forgot to ask if any modification is made to the stock pressure regulator in the tank. With the BoostFueler, I have to believe something was done.

The whole kit was super clean. Looking at it, it looked like it could be installed with a small collection of hand tools and a couple days effort. There was nothing difficult to the eye about it.

Thanks to Bill and Adam for letting me join them! I look forward to seeing them again soon.

 

Wow, cool to finally see a 2.4 with the turbo. Good job guys.

 

rock on about time for 2.4 turbo debut heh cant wait to see full testing results

 

That is awsome congrats to the 2.4 guys

 

Sweet..

 

It seems a return-fuel system is a must for all turbo guys.


06 ss/sc stock

 

HOLY CRAP.... 13.7 and a 101 trap time? **** thats close to a stock trap with almost 1 full second knocked off thats damn...

trap speed even

 

awesome--guy in our club has a 2.4--that's great news!!!

 

Those times are great for the 2.4.......really. I'm just not impressed as much as I thought I was cause I guess I was expecting it to blow Stage 2 SCs away.... but that's still impressive!

 

great times...welcome to the 2.0 stage 2 world. very nice.

 

Remember that this is only a stage 2 turbo system that is running 8 PSI on a relatively small turbo and the only modifications to it are the turbokit and exhaust. Also, this is an automatic not a manual.

 

Awesome!!! Looking forward to seeing some more results!

 

how much more would you be looking at with a manual?

 

Wow , very impressive ....given the small boost level . Basically 8 psi on a stock 2.4 to blow the doors off a stock SS/SC ....I love turbos

 

this is really promising...i was contemplating getting an SRT-4 becuase of the turbo but if thats the stock turbo numbers on the 2.4 i think it easily possible for it to roll with fast ass srt-4's

 

Ohhhhh ****! Ok so now I really can't wait to get my hands on this turbo! Can you imagine what a set of BFG drag TA's on steelies would net you! I wouldn't be surprised to see a 13.5 or maybe a hair better!

This is fan damn tastic!

 

+rep for saying damn tastic. lmao.

 

Thanks man ...... but its FAN-DAMN-TASTIC! You forgot the FAN!

+ rep back bro!

 

+rep for someone who actually reps in return lol

scratch that....apparently youre all repped out from me lol

 

Regardless I still reped you back bro!

 

jackalope i nearly fell out of my chair when i read your comment, are we ready to see possibly the fastest 4 door automatic 4 cyl. ever? you get rep from me. hey pm me about 2.4 emblems, i have six of them, lol

 

very impressive! Just what my car needs--some accleration that doesn't put me to sleep

If I hadn't bought the Formula...

 

sweet!

 

Damn good number's

 

Nice job guys..! Very promising..!

Jackalope- Yu get one rep point from me, just for having so many damn green bar thingys.. Thats insane...! Isnt that legend status...?