I had a race today and decided to go even with the car less than 100%. Down on power is how I'd describe how it felt and some strangeness during the shifts. Anyhow, during the second heat some strange bucking occurred and the sound coming from the supercharger changed. After the checked flag while slowing the car was surging or bucking a bit. When I came to a stop in gear it was revving and almost dying. Got to the pits, put it in neutral and it revved to somewhere over 4500 rpm then I shut it off.
After letting the engine cool down and collecting my trophy (1st place) I did some trackside checking. Couldn't find anything obviously wrong. A Y pipe clamp a bit loose, nothing more. Put it together, started it up, put a hand over the throttle body and no change. 4500 rpms. Home is 100 miles from the track, can I make it? After the original POP I put all the emergency towing numbers in the cell so I got on the highway trying to find symptoms that might indicate what went wrong. Well at cruise the IAT's were running about 60º over ambient. Going into boost, dropped 40º in seconds. This seems to indicate to me the supercharger to intercooler seal is broken. But that's just my guess. Anyone have a clue?

Les

 

I had an intake sensor come loose and cause a lot of rough running until I limped it home... Some sort of leak for sure...

 

Les, have you ever checked the plastic vacuum line under the battery? I have had problems with my car every so often, for over a year. I would check/tighten the plenums, replaced the throttle body rubber gasket, replaced clamps on Y-pipe, checked all known vacuum leaks. Replacing parts may have solved some of my problems at the time but I would still get hicups intermittenly, mostly after I had the AC/heater on. I saw the thread about that line under the battery and decided to check it. It was cracked a couple of places so I repaired/replaced it and have not had a proble since.

Now your problem sounds like a bigger leak than just some pressure from a small line but it may worth checking if you haven't yet.

 

I found an hour and took her apart. The manifolds were perfectly sealed, no signs of leaks. The manifold to Y hoses were perfect, no signs of leaks. The hose from the intercooler outlet to the Y pipe was fine, no signs of leaks. The Y pipe to intercooler hose popped off real easy so I suspect it. The hose isn't broken. Throttle body gasket is perfect. Brake booster hose was correctly installed with the cap. IAT sensor is new and isn't damaged. I pulled the black injectors and have the blues on the fuel rail. The only question now is wether or not to pull the supercharger and intercooler. It looks really simple. I see an electrical plug in the back, the air injection hose, 2 air injectors, coolant hoses, belt, clutch plug, 6 bolts and up and out she comes.

Les

I'll check the hose under the battery. I fixed it 2 years ago with a section of rubber hose, darned mice got to it.

 

Pulling the supercharger and IC is very easy, specially since you already have the intake manifolds and fuel rails off... just a little messy with the coolant in the IC.

 

If you have an engine hoist, it's a cake walk as you can use it to lift the supercharger up and off the block, leaving your hands free to move hoses, wires, etc.. If you don't have one, it's still easy, just more work due to holding it in an awkward position over the bumper and fenders but regardless, what are you waiting for? You're that far in, you have to do it!

 

Rudy speaks and Les obeys. Tomorrow it is then.

Les

 

Here she is, for better or worse. The bolts holding the assembly to the heads were real loose. Should they be re installed with locktite blue? Do I need new secondary air pump gaskets? Just curious, tomorrow I'll be making an order at the MB dealer.

Les

 

I'd use the blue locktite on every bolt. It's not going to hurt anything and it's peace of mind that they aren't going to back themselves out. When I'm doing these, I get every gasket and all the injector seals. The AIR valve gaskets would probably be fine to reuse if they weren't damaged during disassemble but sometimes the coating flakes off them and they are cheap so if you making a list of parts to order, best to do it right and just get them as well. Also, see if Rob has any rubber couplers and if he does, pick those and the 6 clamps up as well. The new ones for the upper plenums have a constant tension spring in them so they tighten up better than the old ones and are less prone to get loose over time. The larger ones don't have this but its good to replace them as well so you're not cussing them when they break during install. Oh and hand tighten them with a nut driver, NOT a ratchet.

Good luck and take care

 

OK, all new gaskets, locktite blue, new clamps ......... do you put a little vaseline on the hoses to slip them on easier? On the injector O rings? I've got the important surfaces almost ready for reassembly. Is the intercooler to s/c gasket in 2 pieces? (pic) How large of a bead of Ultra black is correct. I want to do this once and correctly.

Les

 

Vaseline will help but use only a very small coating on the upper plenums, y-pipe and intercooler outlet, not on the couplings. It's easier to apply a nice thin coat that way.

As for the o-rings, put them on the injectors dry first and then run your finger around them with the Vaseline. Be careful not to get any on the pintle. When you put them in the rail, attach the metal retainer clips before inserting them into the rail and when installing the rail onto the supercharger, start with one corner and work one side in to make sure the next one back is lined up in the injector port and keep going side to side until all 6 are lined up an in the ports, then push the rail all the way down to where it bolts to the SC.

The intercooler gasket is an MLS gasket like a head gasket. When you are laying down the bead of SuperBlack, best way is to cut the tip off right at the narrow end so the bead is only about an 1/16" (2mm) wide and make a bead on the inside of the edge of the gasket as well as the outside and around the four bolt holes. Only put sealant on the two sides that come into contact with the intercooler and supercharger. Do not try to put sealant between them though.

When you're installing everything, do it on the bench before doing it in the car as you can get the Y-pipe aligned with the upper plenums and tighten the Y-pipe clamps where it's easy to get at them.

Good luck and take care

 

Thanks Rudy! Today I assembled the intercooler to the supercharger and did the baked potato mod. I test fitted it several times beforehand so I was aware of all the possible hang ups and set down it down perfectly. Tomorrow I hope to set the supercharger on the engine and start buttoning it up. I did a little porting where the manifolds sit on the runners. I bolted the manifolds on and felt around the mating surfaces and had a ridge all around. I left the supercharger side alone as the gasket was going to protrude in that area if I removed material anyway. For anyone that's thinking of gasket matching the Needswings manifolds, they're perfectly matched to the stock gaskets. All you need to touch up are the runners. We need to talk about the aluminum shavings. When finished I washed everything with soap and water. Still had shavings. Wiped everything down with WD-40. Big improvement. Next I Gunked them heavily and washed once more with soap and water. Nice and clean. As a final cleaning I used brake cleaner. Now that's great stuff. The shavings are so fine you can't even feel or see them but you can see some color when you wipe with a rag. Until you see nothing at all, keep cleaning.
I doubt I'll see anymore power but this could be the last time I have the supercharger off for a long time and seemed a worthy project.

Les

 

think hard about your baked potatoe mod. this takes longer to heat up but also longer to cool down. in your preferred racing it may cost you some power during the 20 min sessions

 

I thought about it a long time after seeing how air flows under the supercharger/intercooler and considered the possible adverse affects. Air will still be flowing underneath while moving so I'm not too concerned. After all, this is a test, only a test, if it were a real emergency we'd tell you to kiss you butt goodbye. But you may be on the money. There's nothing keeping me from yanking it off again if you are. If things proceed as planned, I'll be torture testing my work on the track the 29th of june.

Les

 

I've been a bit remiss in taking pictures. No pics, didn't happen, I know that. Here's my version of the potato. Work's been getting in the way of life so it's still sitting on the desk but tomorrow I should be able to assemble to my hearts content. I improved the wrapping on the entrance hose to the intercooler and a few other details. My I/C to Y pipe hose was "questionable" and for that reason the Aero blue hose is on the Y pipe.

Les

 

I'm on a frustration break so I'm taking advantage to ask advice. I've had the supercharger on and off 4 times today and I can't route the hose underneath in a manner that it reaches the connection at the back top of the supercharger. I looks like it won't reach even without going underneath. I'm assuming it has to pass in front of the intercooler along the coolant hoses but I've gotta tell you, I don't know how to get it there and have it stay while fudging with the stupid I/C hoses. Those who've had it off and put it back know what I'm talking about. They must be situated first with the nose diagonally down and then drop the rear. I've got the schematic of what connects where in my hand but why in the world is the hose to the firewall 2 feet too long and the one underneath a foot too short? Bah! ANYONE OUT IN CROSSFIRE LAND know a trick to help me out with the hose?

Les

 

les im not sure why you would think theres airflow under the s/c. there are many pics of mouse nests and debris under the s/c that remain for yrs. theres little to no flow under the s/c.

get with grip grip. he has pics of the routing under the s/c

 

Supercharger is on. I'm a magician! I pulled the rubber hoses off the nylon ones and switched them. Now it's perfect. All original parts, what else could you want?

Les

 

Regardless of the amount it's more than I thought before taking it apart. There's a nice 1/2 slit under the pulley where air can enter and flow around and down under and lots of space in the rear. Tomorrow I should be firing it up. I packed it in after torquing the supercharger down.

Les

 

Cooling system reconnected, belt back on, fuel rail in, throttle body on, Y pipe on, IAT sensor in and connected, coil packs on, header bolts I can reach tight, secondary air injection connected, electrical connections made, hoses routed correctly. Just manifolds, dual CAI and refilling the cooling system left to go.

Les