Blower bike owners...Has any ever cause engine failure?

[wiggydotcom]

On another site, a Valk owner asked about adding nitrous to a bike. Another owner piped in that nitrous and blowers would be too hard on the engines. I stated that quite a few VRCC'ers run blowers and have put a great deal of miles on them without any lower end failure, which is what he was claiming.

he replied it was on the VRCC that he read about the failures. I've been a member since the old board and I sure don't remember failures.

So what do you say? I know Lamont and Jeff K had rung up a lot of miles on blower bikes.. Anyone else have my back?

Thanks,

[BonS]

I'm the second owner of a blown standard. This bike was modified when it was new, ridden hard and put away wet. 40K miles later everything's still fine. No nitrous though. So far so good. If anything I'd say that the transmission testifies a bit to the engines hard life. It doesn't pop out of gear or anything really bad but it's just not as smooth a shifter as my low mileage Interstate. I would ride it absolutely anywhere without hesitation.

[wiggydotcom]

Thanks, BonS.

[R J]

My blower took out the stock pistons, i fairly short order.

We installed Forged pistons and till I took the blower off I had no more problems.

I'm not saying i had problems later, no that is not what I intended to mean.

I have had no problem with the bad ass MGM till or after I took the Blower off.

I sold the blower and all parts to a guy in Louisiana I believe it was and he sold it to someone in the UK.   I have lost track of the blower & parts.

[Patrick]

There have been several reports over the years of broken original cast pistons.

[BonS]

I would think that the hardest thing to separate out from folks past experience with blowers are those that had issues because of too much timing advance or too lean a mixture. If you're going to change pulleys and add more boost then forged pistons make sense. Forged pistons will also certainly tolerate poor operating conditions such as too much advance and lean running. Terry Klatt of Cycle Tek says that most Valkyrie supercharger performance issues can be traced to poor installations. He put my blower on.

[signart]

NOS will destroy any piston eventually and will destroy all cast pistons in short order.

[Patrick]

Wanna hear a NOS story ? I'll keep it short. I read an article on it back in the 60s. Seemed like the thing to do, so, I got a hold of a bottle of it from the hospital. Since I didn't know what I was doing I installed on an engine I didn't care about [ lucky] which happened to be a SBC. That thing SCREAMED for a very short time before it grenaded itself like I had never seen an engine destroy itself before. And I have blown up my share of engines. Well, I was dumb enough [teenager] to do it again before I found out that you have add some extra gasoline along with the funny gas.

[wiggydotcom]

Wanna hear a NOS story ? I'll keep it short. I read an article on it back in the 60s. Seemed like the thing to do, so, I got a hold of a bottle of it from the hospital. Since I didn't know what I was doing I installed on an engine I didn't care about [ lucky] which happened to be a SBC. That thing SCREAMED for a very short time before it grenaded itself like I had never seen an engine destroy itself before. And I have blown up my share of engines. Well, I was dumb enough [teenager] to do it again before I found out that you have add some extra gasoline along with the funny gas.

Cool story, glad you lived to tell about it. 

[Big Mike]

The key to not blowing up the motor is the setup. If not done correctly, the motor breaks at the weakest point, in our case the cast pistons. However, the compression on our engines is more than enough to handle low amounts of added air from the blower. I know of a few people who blew engines when the blowers first started becoming available. The few that we have set up have been just fine.

[wiggydotcom]

Thanks everybody for responding. I guess from reading your answers, it's a more complicated issue than just a matter of the engines being able to handle it. It depends on who does it and if it was set up properly, how aggressive the driver is, etc.

Maybe it's like the U joint/pinion cup argument. Some say the driveline is the weak link of the Valk. Other's will say, "What problem?"

Onward we trek.

[Patrick]

However, the compression on our engines is more than enough to handle low amounts of added air from the blower.
end quote

I guess I don't quite understand that response. Supercharged engines don't like a lot of compression and our engines are on the edge of compression limits, even being a bit too high. I must say that I have not supercharged a Valk because I could not get answers to my questions. I still have questions about charging these engines that no one has answered. That said, I've been playing with superchargers on other engines since the 60s.
Just to continue. Its my understanding that these engines have broken the original pistons on one side. That leads me to believe there is a baffling issue with the manifold. I've not received any answers to my questions about this and have not been able to look at either style manifold. When I was considering charging on these bikes at least a dozen years ago, no one could answer what I thought were easy questions about these units, not even Bill at Magnacharger. So I went a different route on one bike.

[R J]

Did ya ever talk to JeffK?     He is very knowledgable of these buggers Blown.

[Patrick]

RJ, this was way back before and during the time when Jeff was really 'into' this work. He didn't respond to questions back then either, but, the questions I asked on this board weren't usually directed to any one person. I agree with you that he is now probably the most knowledgable person regarding this.

[R J]

When we installed the Blower on MGM, it was when Lamont and Dragbars were all playing and nobody knew any thing more than what the builder of the Blower would tell us.

Moses, myself, PIBIT, TJ, Dragbars and Lamont well some of the experimental people then.    Me, I just got tired of tinkering all the time.

It was strictly trial and error.

I got tired of always working on the bike before I could ride it.    Took the blower off, put it back to carbs and enjoyed it from there on out.

[Big Mike]

I guess I don't quite understand that response. Supercharged engines don't like a lot of compression and our engines are on the edge of compression limits, even being a bit too high

Rule of thumb for me has been better than 11:1 best results better than 10:1 The valk is 9.7:1. With a proper set up the motor should be fine

[Patrick]

Rule of thumb for me has been better than 11:1 best results better than 10:1 The valk is 9.7:1. With a proper set up the motor should be fine
end quote

Hmm, OK. The engines I've been used to don't like that kind of compression. They don't like anything above 8.5. That last pair of engines I built had 7.5:1 and 45# of boost. The last street engine had 8:1 with 12# boost.

[Big Mike]

You have a Valkyrie engine that is 7.5 and 8 to 1? OK, From the factory they are 9.7 to 1 very good for the amount of boost that gets put into them from the magnacharger and Bills included pulley

[Patrick]

No,no,no,no. I mentioned earlier that I have not supercharged a Valk because I could not get good answers to my questions, not even from Bill. This was about 13 or 14 years ago. So, I went a different route. Today, I'm like RJ. I just want to ride something that I don't have to screw around with. These Hondas are now fast enough for me just the way Honda intended. I'm slowing down with age.
The supercharged engines I'm talking about are a bit bigger.

[Dogg]

I have 8 to 1 forged pistons and carillo H beam rods. 18lb boost. 150 wetshot. I can ride it anywhere you can ride yours. Its all a matter of respect...