V1 Prototype 2: Supercharged Track Goblin - 2009 LT donor

[Adam]

Prototype 2 was a big step toward being ready for production. Fabrication of the chassis took a very long time because as we made each part, we also made each tool so that we could quickly and consistently reproduce the parts for the production runs.

We posted a short build log on the Grassroots Motorsports forums. The first half of the blog details the manufacturing and tooling. The second half covers the actual assembly of P2.

Read the blog: DF Goblin Prototype 2

 

[Adam]

Re: Prototype 2: Track Goblin - 2009 LT donor

The stock Cobalt power makes for a surprisingly quick car (just ask anyone that has ridden in one of our demo cars) but we went and did the next logical step: we installed a power adder... specifically, the ZZP supercharger kit.

ZZP doesn't mention how much horsepower you will get out of the kit. Luckily, we've already dyno tested P2 without the supercharger (151 hp) so we can dyno it again soon to see the difference.

The kit comes with lots of parts (some of which we won't use). Most of the parts are straight from the supercharged Cobalt SS so they bolt right on to the stock 2.2 Ecotec.

The first step to install the supercharger was to get the stock intake and throttle body out of the way. You might see some differences between P2 and other kits (for example, P2 has the fuse box mounted in the wrong place).

The first piece to be installed is the intake manifold with built in intercooler. It is a water to air intercooler system that uses an electric pump to move the coolant from the intercooler to a heat exchanger.

Next you bolt on the supercharger. The ZZP 2.2 liter kit comes with a 3.4 inch pulley. If you go any smaller, you will probably need to replace your rods (preferably before they go through the side of your cylinder block).

We had to mount the supplied idler pulley differently than they instructed. Since the ZZP kit is generally installed on full bodied Cobalts, they assume you will have an AC compressor. We don't have the compressor on P2 so we had to reroute the belt. We made aluminum standoffs to put the idler above the alternator so that we would have a nice wrap around the blower pulley. We were able to buy a belt from the auto parts store to fit our new arrangement.

The last big hurdle was the heat exchanger. The supplied exchanger is meant to go in front of the radiator of a stock Cobalt. It is very big. Instead of using their exchanger, we decided to experiment with using the AC evaporator from the donor Cobalt as an. It is about 60% the size of the ZZP heat exchanger. We routed the hoses between the intake, pump and exchanger and filled it all with coolant. We also bought a 9 inch fan to keep air moving across the exchanger.

We don't know if the evaporator will be sufficient but this is the only car we plan to try it on. For other supercharged and turbocharged builds, we are going to run a heat exchanger at the front of the car with air ducts bringing in air from the control arm area. Water will run in tubes from the front, through the tunnel and up to the intake (supercharged builds) or to a water to air intercooler (turbocharged builds). P2 is a bit different up at the front so we couldn't try out this design.

We got a tune from ZZP and used HP Tuners to flash the ECM. The tune needs some tweaking but we will figure it out on the dyno soon. Even without the tweaking, the car is completely different now. It pulls harder from low RPMs and just keeps getting stronger until red line.

Anyone trying to decide between base model and SS should definitely consider going base model and adding a supercharger later.

 

[smithvmi]

Adam,

Where did you end up putting the IC pump? Im trying to attach it below the intake manifold but holes aren't lining up.

EDIT: They don't line up because I am still waiting on a part (#12586632, for all those interested)

 

[Adam]

We just mounted the intercooler water pump to the Goblin frame above the fuel tank.

One thing we had to change was the lower water fitting of the intake manifold. It points straight out at the fuel tank in the Goblin. We copied Jay's idea and pulled the fitting out to install a 90 degree fitting. We tapped the manifold with a 3/8 pipe tap and screwed in the 90 degree fitting.

 

[smithvmi]

Do you have any pictures of the final product 90 degree fitting?

 

[Gage]

It appears that going with a base model Cobalt will save a lot of money. However, is that a wash when factoring in the cost of the supercharger kit you pictured above? What does that kit cost?
(Yes, I'm going over to look around at ZZP's site.)

 

[Gage]

I found it. I think.

 

[smithvmi]

The zzp kit is a bit more than twice the cost of piecing your kit together from used parts. The 750 starting price doesn't include the TB, intake or blower. And the zzp kit has parts you don't need.

Consider also the type of driver that had a ss cobalt vs a ls or Lt. The ss donors I test drove were ROUGH. Just my two cents and your mileage may vary.

 

[Paperscale]

Reviving this, because I like the idea of adding the SC to an easier to find base model. I was wondering what the Dyno numbers ended up being. Also, like it was mentioned, the kit has extras you don't need, and stuff you need to add as well. It ends up costing something like $1300 to add a supercharger. It's nice to have new parts, but I'm questioning if it really is better bang for your buck than just buying the SC model to begin with.

I'd assume you'd need to add extra parts from DF as well to make it work. So while the donor car and kit price may start cheaper, it sounds like you're about at the cost of just using a more expensive SC model from the start.