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Long Term Serious Basch Boost Supercharger Problem

1 May 2004
Durham, NC
Hello Fellow NSX Friends:

I do hope that you remember me, as I was at one time a very active member of the NSX Community, but have fallen into inactivity over the past few years, primarily based on the inactivity of the car itself. I am going to explain how this all came about.

I also want to say that I have always felt it a privilege to be among the NSX Club Members as they are by far the most outgoing, helpful, interesting group of any motorsport organization I have been a part of.

I am not going to try to point fingers regarding the problems I have at this point. I simply want to get them resolved. I have endeavored to get these problems resolved with inquiries various times in the past but this time I am going to see it through to the end no matter what the eventuality is. So, please be aware that if you try to help me with this, I am actually going to use your help. While this question may be wordy, it is going to be posted in the technical forum because the majority of the problem, in fact the whole series of problems are all of technical nature and that is the kind of solution I am seeking now.

Brief prehistory of car:

Bought a 92 NSX in 98 with 33,000 miles on it.

Replaced Clutch a couple times.

Found car to be in snap ring range, although never had the problem, but installed Comptech 6 Speed with 4.55 R&P and power grip clutch. I have had very little problem with this installation and single out as the thing that has made the car a lot more fun. You want the snap ring tranny? It’s in my garage.

I was tracking car perhaps 5 times a year at that point, driving it as a daily driver a lot. Going through a lot of tires, but that was all, and expected.

In 2000, attended NSXPO in Atlanta. Clutch started slipping on morning of Road Atlanta so I gingerly drove it home instead. But my clutch problems are pretty much gone now.

Then in 2002 (I believe July) the trouble starts. The Basch Boost Supercharger becomes available. I decide based on its non intrusive nature compared to others to get one added to the car. I believe in July, Mark Basch makes a trip to the Raleigh-Durham area where he works on maybe 10 NSXs from DC to Atlanta that have driven here to get Superchargers installed or adjusted. This was not the first group installed as many West Coast installations have already been done.

Mark installs the Supercharger on my car. The car dyno’s 360 at the rear wheels. Everything seems to be going pretty good. I’m happy for the time being. But then I find that I have a mysterious problem. The car frequently smells like anti-freeze and I have to keep adding coolant to the new coolant tank (it is changed due to the supercharger). I take it to my Acura dealer and they pressure test the system. They can not find a significant leak anywhere, except a little shows up on the bottom lip of the triangular tank. I find that consistently I can feel some wetness there—I don’t think it is enough to account for this much loss but it is all I can find. If the car sits even after a hard run, none ever reaches the ground. Ever. I bring this to Mark’s attention, but he never does anything to assist in this. No offer of a new or replacement reservoir. So, from that point on I have to add water to the car every 100 miles and if I ever dare track the car, between each run group. The flaggers stop me because it smells like antifreeze but they always let me go back out on track because on inspection it can’t be found anywhere on the car. The car rarely shows any signs of overheating. So, as long as I watch it very carefully in the summer and don’t try to track the car much any more, it’s okay. No foam in the oil or anything that would indicate an internal leak.

This problem has never been rectified. Anyone with any ideas let me know. I think I have checked everything anyone has ever thought of by now but will reconfirm results or check again.

Some time after installation of the Supercharger, an unexpected package arrives at my house. It contains a black box with two screw hole mounts and two sets of wires coming out of it and one little hose. The wires are bundled but loose on the ends. There is no explanation with this device, only a note that says, “Call Mark before installing”. NO REASON IS GIVEN WHY I WOULD WANT TO CHANGE THIS DEVICE EVEN IF I KNEW HOW TO INSTALL IT or where it went. As there are no warnings with it, I assume it is some kind of performance enhancement and let it go. I don’t really care if it would give me another 10 horsepower. Getting in touch with Mark is very difficult anyway.

More than a year later I am at NSXPO in Corning, NY in 2004 and talk to some members about this thing. “Oh, yeah, without that change the car will probably experience detonation and ruin the compression of the engine.” I speak to Mark about it directly a couple times. Again, no explanation is ever given as to why I was not informed of the impact and why there are no installation instructions. We exchange a couple emails and a couple phone calls, but still there are no instructions on how or where to install this thing. Here is where I made a bad assumption: That it must be so damn obvious that it must not need instructions. Also, at NSXPO 2004 I make a copy of the complete Basch Boost Supercharger installation instructions. Well, between the 1200 page NSX Shop manual I have and the Basch Boost Supercharger book I am still uncertain where this thing is. A knowledgeable mechanic friend of mine and I take some guesses and go looking for it, but can’t find it. This is 2005 now and I no longer track the car and am afraid to take it much over 5000 RPM for fear of detonation. So the car which I loved to drive and was going to be one of those 100K+ NSXs easily hasn’t had 10,000 miles put on it in the last 3 years. It sits dormant in the winters, which are mild in NC. I finally got it out again this month and this time promised myself to take this to completion this spring and summer.

Oh, detonation? Apparently the Basch Boost Supercharger destroyed several engines and Mark worked to make some reparations, but the only way to tell if this happened is a compression check and I don’t have any way to get the damn thing off to get that done. I did have one mysterious incident on track after installation but before the new box was sent out having to do with a sudden oil loss on track and loss of power, but then being towed to the pits, checking the oil level and finding it not much below normal and the car running fine (I drove it home 60 miles that day). It only happened that once.

So, this week I took the car, the book, the box, to my local Acura dealer who has been servicing the car for 8 years. They did the transmission swap, etc. My question was simple to them, “what is this damn box thing and can you replace it for the one currently installed; there has to be one on the car that looks like it.” They found something that they thought was it in the trunk on the wall between the trunk and the engine on the driver side. However, the wires coming out of it don’t correspond with the number of wires on what appears to be the original one installed with the Basch Boost Supercharger. Maybe that isn’t the thing at all. They are a really good dealership. They won’t screw with anything they are not sure that they know how to do. So, it is here on my couch. The car is still in its original supercharged state, me worrying about detonation, dealing with the water leak and afraid to have any more fun in the car.

I have been looking at all the NSX Prime forum stuff today and find all kinds of issues and problems with fuel mappings and things. It looks like this Basch Boost Supercharger was a very bad idea for me and that it may or may not still be in existence, and Basch Acura has changed to Basch Accurate and moved if they are still around at all. If the latter problems mean that it won’t give you as much boost as originally predicted, I can live with that. I just don’t want to blow the engine up and be able to have fun driving again.

So, I have significant technical questions here:

CAN ANYBODY help me to figure out where this box goes and how to connect it?? Then I may move to question two:

What would any of you do about this water loss problem??

And finally if we can’t get this thing worked out,

IS THERE ANY WAY TO GET THIS CAR BACK TO STOCK?? I still have the original parts that were changed…and would be gladly willing to buy replacements for anything that has gone bad (like the original plastic water jug—that worked just fine). My Acura dealer and the mechanic there who I have a lot of trust in won’t do it. It is not a matter of policy, but he won’t get into anything he has doubts about, and I very much appreciate that. WHAT HAS TO BE DONE?? WHO CAN I GET TO DO IT?

Without putting a dollar amount on anything, a normally aspirated NSX that you can drive anywhere and have fun with any time is worth MUCH MORE than a supercharged NSX that you are afraid to do anything with.

I know that everyone’s time is valuable, and I promise I will follow up on this with anyone willing to give advice. CHEN MOTORSPORTS GANG: There is nothing I would like more than to see you at Roebling Road this year, VIR and NSXPO—Wei Chen, you may no how to direct my problem, Mark in Atlanta, if you think this can be worked out there, I’ll come to Atlanta. Scott in Tampa? Refer me to someone. You would have been seeing me in the past couple years if it weren’t for this. Gang around DC? I can come there too. If anyone knows ANYBODY in NC, let me know.

Mark Bastanza, maybe you can help or find the person I need to talk to.

People someone reading this I don’t know in person yet, I find you very valuable as well. The NSX Ownership group is exceptional, and that is part of something that I can’t take part in with an NSX in the garage either.

Mark Basch? If you are out there, please contact me with a concrete answer. Diagrams. Schematics, explanations.

I am not worrying about disclosing this problem on the lists, because I would never sell this car to anyone without full disclosure.


I am going to post this to the NSX Technical Group, Supercharger group and on the Forum and the NSX Tech list. I apologize if this cross posting is unusual, but I have been out of touch for so long, I am not sure where the most effective post will go.

I want to say thanks to everyone and that I do miss you guys.

Bill Harpe
92 NSX
Basch Boost Supercharger
Comptech 6 Speed with 4.55 R&P
Dali Racing Sways (never had a problem).
Raleigh-Durham-Chapel Hill, NC
IIRC the early BBSC kits had problems with the overflow tanks.
Have you pressure tested just the TANK. Then check the two new longer lines added with the BBSC. This is the only thing the BBSC has changed in your water system so I start there first. As far as the little black box…DON’T GET ME STARTED.<O:p</O:p