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GruvenParts.com Corrado SLC Supercharger Build Thread

60K views 272 replies 62 participants last post by  GruvenParts.com 
#1 · (Edited)
Welcome to the www.GruvenParts.com Corrado SLC supercharger build thread. This will be a pretty standard build centrifugal supercharger installation on a 1992 Corrado SLC, but you will get to see some of our crafty billet goods installed on the VR6 in the meantime.

There will also be a twist at the end, this wont be your typical slipping serpentine belt S/C set up. It wont be a mega bucks noisy all cog pulley conversion either. And we wont tension the serp belt so far as to break pulleys (and bearings) in our quest to prevent belt slip on the charger pulley. I promise : It wont slip a bit at whatever pressure we run.

So sit back, enjoy the pictures and write up, and feel free to drop an email or call to us if you have any questions, our contact info is at the bottom of every thread we post.

** Day 1 **
Tear down, and a look back at some track pics to keep us motivated …

Lets start with reminiscing. Here we have the pristine 92 Corrado SLC in full swing at one of the best road courses in the world, Road Atlanta.


Corrado exiting turn 10B, getting lined up for a slight right under the bridge and down into turn 12. You will be FLAT OUT from this point all the way until just before the apex of turn 1 (a half mile away). And it is anything BUT straight, and there are mean walls, gators, and other obstacles which have claimed many expensive vehicles (and lives) along the way. Hang on!


Getting light at the top of the esses. Did I mention there are A LOT of corners here to ball up your ride?


Corrado entering turn 1. Flat out? Hell no. That’s why instructor Reinhardt is telling me “You gotta have BALLS man!”. He is right, look at all the horsepower behind me. To be quick on this track, you have to keep momentum. He later showed me how it was done in his 85 Golf GTI. Lap after lap of full throttle, full brakes, but mostly full throttle. When we passed a 400 hp Corvette in a 105 hp GTI, I started listening more closely. Its obviously NOT about power, it is about driving skill. But power doesn’t hurt either…so lets get on with the build …




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My V9-F trim Supercharger Set Up on 1992 Corrado SLC, dizzy

Charger - Vortech V9-F Trim
Charger max impeller speed : 53,000 rpm
Charger gear ratio (impeller to pulley) = 3.54:1
Vortech tech support : 805-247-0226 (M-F 7-3:30 PST)

Belt : Stock 1360mm
Charger Pulley : GruvenParts.com 2.4” 7 rib
C2 Chip
30# injectors


Charger rebuilt in 2010 by superchargerrebuilds.com. Good price/lead time, but I probably wouldn’t use them again due to poor communication during the process. I would suggest http://www.928superchargers.com/

Air Assist Valve(the small brass valve attached at the oil feed line on the charger):

New valve bought from Vortech. However, you can buy it here for $30 cheaper than our friends at Vortech :

http://www.clippard.com/part/MJCV-1

Clippard MJCV-1 Jumbo Check Valve 1/8 NPT Female to 1/8 NPT.

When you install this, the arrow on the valve MUST BE FACING THE OIL FEED LINE. It should block all flow of oil to air intake side, and allow air to push in from air intake side at 1 psi differential. Don’t install this thing backwards or you will flood your intake with engine oil ! And no, you cannot delete this valve. This helps push oil out of the charger and works very well.

Oil feed/return :
I used the VF supplied oil feed line, tapped into the filter housing. I tapped the oil pan for the return. Some swear by tapping the block for the return, it is not proven which method is better. Tapping the block will ensure proper oil flow and probably the preferred method, however, I just didn’t want to drill into my block so I welded a return onto the pan.

Intake set up :
VF Engineering supplied pipe from charger to t-body. I needed a silicone 2.75-3.00 adapter at the t-body because the pipe VF supplies doesn’t match the diameter of the t-body (nice work, guys). This causes the silicone 3” adapter they do provide to pop off under high boost. This part is the correct part for charge pipe to t-body adapter :

Vibrant
http://www.summitracing.com/parts/vpe-2712

From the charger inlet (3.5”) to the VF supplied Charger Feed Duct (3”) I used this adapter :
http://www.summitracing.com/parts/vpe-2716b

At the exit of the VF supplied charger feed duct, I used 3” to connect to a 2” PVC tee. The bottom leg of the tee has a bushing installed, with a drain valve. This creates a small (1/2 qt) catch can with drain which still sits up slightly higher than bottom of air dam. The middle outlet of the tee goes to this inlet tubing, again using a small piece of 3” silicone tubing to adapt to this :

Spectre
http://www.summitracing.com/parts/spe-8741

Not a big fan of this stuff because it creates turbulent air flow, but I don’t know what else provides the needed flex to connect to rest of system.

The Spectre tubing then connects to a 36” piece of 2” PVC, again using a 3” piece of silicone tube as adapter.

This 2” PVC 36” length runs across front of car behind the air dam. This is attached to the radiator core support using 3” hose clamps, insulated with rubber hose.

I used more Spectre flex tubing on the drivers side end of the 36” PVC tube which goes up to the the MAF and snub cone air filter. The MAF is located where the horns used to be, and is attached via 3” hose clamps to the horn bracket.

I made sure to replace the small plastic air dam cover mounted on the bottom of the drivers side, as this prevents air from swirling near the cone filter.

More Info :

I sanded then painted the PVC flat black, it actually looks pretty stock and you couldn’t possibly knock it loose.

Another route you could take, if you wanted larger diameter intake tubing is to use a 3” aluminum tube across front of car. You can buy that here :

http://www.onlinemetals.com/merchant.cfm?pid=7054&step=4&showunits=inches&id=71&top_cat=60

Get the 36” length.

However, on a Corrado, you would need to hack into the radiator cowl if you wanted that 3” tube to fit up under the air dam and not hang down too low. On a lowered Corrado, you already scrape the air dam, so you cannot have air intake tubing lower than the air dam itself. If you did go this route, you could use a 3” PVC tee rather than 2” PVC tee. You would need to buy 3.5 to 3.0 silicone adapters to install the 3” PVC tee. I really don’t think you would notice a difference, but some may want 3” intake vs 2” intake.

MAF Placement

Is critical. You cannot have any residual air blowing past it, otherwise it will trick the MAF and wreck havoc on the A/F ratio. Once that happens, hold on for the bucking, dying bronco syndrome. ISOLATE the MAF and cone air filter as much as you can. It cannot have any air blowing over it. Also, the MAF usually needs to be at least 24” from the charger inlet. Some have had good luck placing it on the passenger side but not me. Mine was only happy up under the battery tray on drivers side. I like it there also because it’s a relatively dry area.

Checking for Boost Leaks

I was getting some pretty bad boost leaks from the crappy VF engineering charger tube. I connected air tank to my PVC tee on my air intake catch can. Blocked off the air intake over to MAF/cone filter (using a plastic oil filter housing cover and hose clamp). Also removed the recirc line coming off back of head.

I also disconnected the return line off the diverter valve, just to see how much boost was possible before valve opened.

Then, I soaked ALL the presurized connections with soapy water spray and applied 10 psi to into the PVC catch can. You can find the leaks very easily because the soap bubbles expand where the air is leaking. I found my VF charger tube to be leaking at t-body connection and also at the ISV block off. I re-did both connections, now no leaks.

Kind of a neat/quick way to check for boost leaks on simple intake system like this. Just make sure to remove that recirc line from back of head, otherwise your dipstick will hit top of garage ceiling ;) (ask me how I know that...)

Ive also seen some actually blow smoke into the system and then look for the smoke rising out of the leaks. That method is better if you have complicated plumbing where you can physically see all the connections (ie, intercooler set ups). You will find leaks in hidden joints because smoke will rise from engine bay, easier to see. They smoke a cigarette and blow the smoke into the catch can, then pressurize system. Cheap way to do it, you could also get a smoke machine.


I’ll keep posting more as I have more time, hopefully pictures as well…
 
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#5 ·
:popcorn:

1 question though......Where's my damn coolant flange/therm housing made of aluminum?!?!?!?!?!?! :p
 
#9 ·
OK end of day 2.

Took out the subframe to provide access to drill out the block for the s/c return line. Also removed the intake mani to put in the red top injectors, and pulled the charcoal canister out. Hmm where will that be relocated to? The charger intake will be stuffed down that hole.

Bunch of parts on order, might as well replace temp/press sensors and such while we're at all this.

You can finally see the GruvenParts.com 1st gen billet crack pipe from 2004. Still works perfectly, drain has been used at least a dozen times and is still functioning perfectly. If it wasnt connected to that Godforsaken plastic thermo housing on the other end I would feel better. Lots more plastic stuff in there though needs the billet treatment.



Next step will be to clean the engine up, its a mess right now. Tire marbles from track days, dirt, grime, ect...

We'll drop in the red top injectors, put the intake mani back on, then drill baby drill the return line into the block...kinda nervous about that 1. Although if I screw up it really wouldnt take all that much more effort to pull the whole motor/trans out and really go to town. Maybe throw it all in the backyard in favor of a 3.2L R32 set up ... wish me luck ! :beer:
 
#11 ·
I appreciate that suggestion!

I spoke with Vortech directly on it, they tell me the oil will not flow correctly thru the charger if the return line is submerged in the pan.

Im not really sure why that is, being that the supply line should be pressurized enough to push oil thru, but they absolutely insisted that the return line be tapped in ABOVE the oil level ...

But I will think about it some more, yeah I would love to just weld a bung onto the pan ... thanks. :beer:
 
#13 ·
Awesome! Watching:thumbup:
 
#15 ·
Ok so just in time for fall/winter we have a new A/C system going in.
The compressor sounded more like marbles in a blender, and after this
summers 100F+ heat the Corrado ended up on the sidelines most days.

I figure while the whole front end is off why not go in with a new
compressor, condenser, hi/lo switch, new o-rings, receiver dryer, and
expansion valve.



And the red top injectors are now installed with some new injector o-rings.



Time to design the s/c pulley. Stay tuned …
 
#16 ·
Have you thought about drilling the block where VF says to drill it?

I never wanted to drill my block either, but VF insisted that the line had to be above the pan.

Just make sure where your drilling does not interfere with anything else on the inside.

Not really that hard to screw up, just take your time. :thumbup:
 
#17 ·
yeah ive thought about it. i load the drill up with a new carbide bit, then blip the drill motor on and off, on and off, stare at the engine block thinking wtf am i doing ...


a few posts up you can read another savvy individual with s/c installs recommends just welding a fitting onto the pan high up.

Or ... keep it really simple and install a tee fitting on the oil drain plug threads.

The supply line pressure is going to be 40 psi, that should be more than enough to force the return oil back down into the pan, even if it is submerged in 3" oil.

For some reason vortech is quite particular about tapping block though, they must know something I dont.. Usually the case ... :beer: I will think some more. There is still work to be done before we cross that bridge.
 
#19 ·
Or ... keep it really simple and install a tee fitting on the oil drain plug threads.
I would be worried about bottoming out and losing that setup completely. Even if your not low, thats the lowest point on the car.

Honestly, if I were to ever do it again, I would probably tap the block like I did before. Its not so much of a hassle, especially if you some how manage to bust out oil pans left and right.

Plus its what the manufacture recommended, and its tried and tested.

Anyways, I am watching this thread for more to come :thumbup:
 
#23 ·
Not sure how different the various Vortech units are, but for reference I just removed a Eurotech V2 system from my Mk3 GTI-VR6. It used the oil pan drain, and functioned flawlessly for 7+ years and probably ~75K. During that time, I never had any issues with the water pump or other accessories. I think the key for these systems is to not get too greedy in terms of boost. My system was tensioned only until I saw 8-9psi at redline. It was a lot of fun, very driveable, and easy on the drivetrain.

Good luck with the build - looks good so far.
 
#25 ·
I've run turbo systems before with the turbo return line going straight into the oil pan drain as well, no problems whatsoever.
 
#32 ·
I meant he'll need 12psi to keep up. "Sven" is an 05 Saab turbo wagon that inexplicably hauls ass. If this charger puts out 12 psi then I went way too small on the pulley design, not even sure the motor would hold together. Shooting more for 8-10.

Updates ... I need to call in a sick day ...
 
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