Viper hot start issue found

[stingray719]

I went out to the garage and tore the hood off my Viper and gave it a once over. Then I saw something that made my jaw drop. The radiator is 3 3/4 inches from the intake opening and the fan when it kicks on blows hot air directly into the air box. WOW!

Let me make a guess as to the hot start issue. I tested and if you are warm enough for the fan to come on, when you shut off the sled the fan runs for a bit pushing more hot air under the hood. Now when you turn the key on the fan blows hot air for a moment right into the air box. At the same time the fuel injection is forcing gas into the engine for the start procedure. This would explain the tricks people have for hot start. And would also explain why some of us do not have the hot start issue and some do, as to where they ride and snow on the radiator.

Lets look at this another way. Go out to your car or truck and if it was made in the last 15 years or so I can guarantee your air intake is out the front for cooler air than is under the hood. Many reasons for this I am not going into here, the point being this set up on the Viper had to have been a last minute mistake as no self respecting engineer would put the air pick up directly behind the radiator. Or maybe a space issue?

Bogging and blown engines, snow on the radiator creates steam and the radiator blows it directly into the intake. Adding water to your fuel mix leans it out and can cause detonation if circumstances are right. I have no proof this is what has caused several boosted engines to go boom but I strongly believe it.



So I am going to try a radiator delete anyways, but I thought about a fix for the girlfriends Viper. The quick fix I came up with was to reverse the wires on the fan causing it to push air out the front. As the fan is only needed when sitting still or idling this should alleviate most of the hot air/steam issue. Will still have hot air from the radiator under the hood but at least the fan will not be forcing steam into the engine.

Do not try this until I have time to test it! A friend back east is till riding his Viper in the local asphalt drags and has agreed to test this, I will post his results when I get them.


Intelligent response or questions welcome, please try to be adult.

 

[christopher]

Yup, no doubt about it, this is going to be an interesting season..


Sent from my iPad using Tapatalk 2 pro.

 

[bholmlate]

Well The only reason i could ever see for doing anything remotely like this is to pre-heat the cold air in extreme cold climates for trail riders and lake runners back east. of course that is the market where Yamaha has all their research and biggest market share. there is a chance that the throttle body could freeze up do the the amount of cold air being sucked into the motor in sub zero temps. But of course this could also cause vapor lock and other problems on extremely warm days as you eluded to when you are trying to keep the intake charge as cool as possible.

I am not sure reversing the fan is a great idea either air like any fluid will take the path of least resistance not that the radiator is any less restrictive then the opening in the air box but when the fan is running there is the potential to disturb the air flow as it is trying to enter the air box

 

[stingray719]

Well The only reason i could ever see for doing anything remotely like this is to pre-heat the cold air in extreme cold climates for trail riders and lake runners back east. of course that is the market where Yamaha has all their research and biggest market share. there is a chance that the throttle body could freeze up do the the amount of cold air being sucked into the motor in sub zero temps. But of course this could also cause vapor lock and other problems on extremely warm days as you eluded to when you are trying to keep the intake charge as cool as possible.

I am not sure reversing the fan is a great idea either air like any fluid will take the path of least resistance not that the radiator is any less restrictive then the opening in the air box but when the fan is running there is the potential to disturb the air flow as it is trying to enter the air box

In this particular case the air enters low and with the fan reversed pulls that air up and blows it out up high on the hood. The only down side I can think of is that it would be like a Honda Goldwing 1800 in that blowing air into the wind means marginal cooling at certain slow speeds. When sledding the only times I have seen the fan on is when idling or going very slow. But your point Is taken...and this may not be a perfect fix but for me blowing steam into my intake is not an option.

 

[tundramonkey]

You may want to wire in a switch that will allow you to reverse polarity only when needed, like a ceiling fan so to speak. This would allow normal operation the majority of the time and the reversal only when needed.

 

[stingray719]

You may want to wire in a switch that will allow you to reverse polarity only when needed, like a ceiling fan so to speak. This would allow normal operation the majority of the time and the reversal only when needed.

Honestly, I never want to blow hot air in under the hood. When the snow flies I will have two Vipers, one with reverse radiator fan and one without a radiator at all. Testing should be interesting.....

 

[kanedog]

Have a look at Aerocharger Turbos and some other turbo setups.
A good number of them just have that dome screen over the under hood turbo intake, sucking hot, under hood heat and fine belt dust particles right into the motor.
I would say your right on par with the others!

I don't know if it came out like I meant, but the above comment was sarcasm.

 

[stingray719]

Have a look at Aerocharger Turbos and some other turbo setups.
A good number of them just have that dome screen over the under hood turbo intake, sucking hot, under hood heat and fine belt dust particles right into the motor.
I would say your right on par with the others!

I don't know if it came out like I meant, but the above comment was sarcasm.

Bought a supercharged Phazer a couple years ago and it had that....just a screen over the super. Didn't take long for me to put an out of the body filter on it.

 

[kanedog]

I hear ya. You kinda say to yourself, " what were they thinking?"