Mikes Extended, Full Frame Goblin - 2009 Cobalt LS with 135k donor

Rauq

Rauq

Goblin Guru
Left turns would be when the pump is starved for fuel with a low fuel level. When you installed your pump, did you modify the bucket in anyway way? I don't know if you ever confirmed whether your bucket has the venturi or the check valve in the bottom, but both serve to keep fuel in the bucket and at the pump even when the inlet is momentarily uncovered from fuel.
 
TravMac

TravMac

Well-Known Member
I had a similar issue in mine with a modified fuel bucket. Feels like the car lost all power? Picks right back up when the car straightens out? That's exactly what I had felt. Instead of pulling fuel from the reservoir, my fuel pump was pulling directly from the tank, and going dry in a hard left with less than 3/4 of a tank (per the gauge which is certainly not the most accurate). Not sure why you're not seeing it in only first and not other gears, but that also may be for really hard accelerations when turning I'd guess.

I'd take your pump out, make sure you are pulling from the reservoir bucket, and not directly from the tank. If you don't have it modified, make sure it isn't cracked and is holding fuel. Trying to reproduce this too much will certainly lead to damage to the engine. If you don't drive hard in those turns, then you should be fine for the short term!
 
M

mike_sno

Goblin Guru
Thanks for all the comments. Have not really had a chance to investigate further, but based on the comments I believe I found the problem. When I installed the new fuel pump I modified the top part of the bucket since the new pump was longer than the old pump. I did not modify anything and even reused the old filter before the pump at the bottom of the bucket. However, the return line did not fit in the same spot anymore and I thought I could just return the line and let it end up somewhere in the fuel tank. Originally the return line ended up at the top of the bucket. Now it seems I know the reason for that :D I am not 100% where the return line ends up right now, maybe its hitting the bucket some time, but not always... Anyway I will secure the return line and see that it always flows back in the bucket.

Other than that I removed the gray mechanical fuel pressure limiter from the standard fuel pump assembly when I switched to the boost reference system. This part was located at the top of the bucket. No changes I remember at the bottom of the bucket.
 
M

mike_sno

Goblin Guru
Hi Forum,

I remeber there was someone saying there is a coolant hose for the LSJ which is from a Ford F150 truck or so? which connects in one part from the top of the engine to the frame connection. Does anyone know the part number for this part? I have puzzelded it together with a couple of individual hoses, but would love to get that area cleaned up.
 
M

mike_sno

Goblin Guru
Ok, might not be ideal but I don´t want to weld anyhting to my frame and try to move my center mounted heat exchanger to the side to get it some fresh air and possibly make a plexiglas between above the rear seats. The wind was always kind of weird and I want to get rid of the fans as well. The goblin sounds like a driving crypt rig :)

I like the tilt back design a lot better, it just looks better. I wonder how much air flor disturbtion comes from the rear wheels? Do I need to protect the heat exchanger from flying rocks from the wheels?

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Chris_WNC

Chris_WNC

Well-Known Member
I have a plexiglass piece behind my seat and it does wonders for heat and noise. My son will ride in it now with it on there. I can send you my drawing if you’d like.

On the side mount, with the soft and sticky tires that we run, if you hit any sand or gravel it’s going to fly up at the wheels. I have r888r’s and a gravel driveway. I have to vacuum the little sand and pebbles out of the Goblin after every ride. It gets everywhere. Top of engine, between body side panels and tube, seats. lol. It’s a mess.
 
Traé

Traé

Goblin Guru
mike_sno said:
Ok, might not be ideal but I don´t want to weld anyhting to my frame and try to move my center mounted heat exchanger to the side to get it some fresh air and possibly make a plexiglas between above the rear seats. The wind was always kind of weird and I want to get rid of the fans as well. The goblin sounds like a driving crypt rig :)

I like the tilt back design a lot better, it just looks better. I wonder how much air flor disturbtion comes from the rear wheels? Do I need to protect the heat exchanger from flying rocks from the wheels?

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I saw someone on Facebook (@Corey) use what look like HVAC radius 90s on each side as a scoop to push air over either a HX or an oil cooler (or one of each). I think it looks good, you may be able to secure it another way so you’re not welding.

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I would say yes to protecting it from rocks!
 
M

mike_sno

Goblin Guru
That's awesome! I was hoping it would help with heat and noise. Glad you could confirm that. Are you running a rear diffuser as well?

Would be great if you could send the that drawing. What material did you use?
 
Chris_WNC

Chris_WNC

Well-Known Member
mike_sno said:
That's awesome! I was hoping it would help with heat and noise. Glad you could confirm that. Are you running a rear diffuser as well?

Would be great if you could send the that drawing. What material did you use?
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I used smoke grey tint polycarb that I got on Amazon. My sheet was 24"x48"x1/8" and it was laser cut on a Kern cutter. Sending you a message.
Edit: I do not have a rear diffuser.
 
M

mike_sno

Goblin Guru
Did the first test drive with the heat exchanger mounted outside (tilted back mounting position). I had a log running and a first quick comparison showed slightly lower intake air 2 temperatures. Around 140F max. However, while driving the heat exchanger is in now way in full airflow. The shadow or disturbance of the front tire and being to close to the frame. Tested reliably with my hand while driving. LOL. Anyway, I felt quite a bit more air flow from the back to the front. Will start with a cardboard template from the drawing of @Chris_WNC to get that under controll.

Next mounting the front wing. Have a first design ready to be machined and tested.
 
M

mike_sno

Goblin Guru
Took the Goblin for a ride this morning. Got the new rear window installed, thanks to @Chris_WNC for the drawing. I can drive now without hearing protection!

The little air tunnel on the heat exchanger made some difference, but I still feel like the fans did a better job. However, I can feel a warm air flow below behind the heat exchanger. Will probably mount the fans again and make another log.

The front wing made the car for sure more stable, when I go off throttle at speeds over 60mph I don't need both hands at the steering wheel again. Still not perfect, but progress in the right direction.
 
M

mike_sno

Goblin Guru
Installed a sheet metal under the engine. For whatever reason I feel like that made the engine more quite as well. Booked myself a dyno session and will advance from street tuning to dyno tuning. Hopefully the weather next weekend is good. Than I need new tires and should be good to go for Autocross in September. Yeah!
 
Desert Sasqwatch

Desert Sasqwatch

Bigfoot Goblin
You only have 5.5 inches under the rear of your Goblin? Your ride height is pretty level then - at least compared to other Goblin builds which typically have 6-7 inches under the rear of the frame. A diffuser can be built to create some downforce, but it all comes down to the design. @Justinreed7 has an effective diffuser under his Goblin, but does mostly track time with his car so the diffuser can extend lower than a strictly street car. @Rttoys (Russell) has a diffuser under his Goblin, but I'm recalling he had moderate success with it for downforce versus ground clearance. I do plan to design up a diffuser for my Goblin, once I get that far. I have another aluminum road sign that has sacrificed it's usefullness (pretty beat up) and I will not lose any sleep over dinging it up if the ground clearance is a little too low. ;):D
 
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