I have the HSP twins for abt 6 months now , cast wheel, std cover 475/stock , am I the only one that thinks the whistle is quiet in the cab? Maybe I'm being to particular. They run great, there is no doubt they are very strong. ....I don't mean out of the exhaust sound either
Twins quiet?
- Thread starter SmithLBZ
- Start date
The whistle of my twins is way louder than the stock turbo ever was, but not as loud as my 4094vvt. That thing whistled all the time. I kind of like the whistle of the twins. Its ever so faint while driving normal, but when you lay into it and the turbo spools then she makes some noise.
the 475 i had and the batmo reworked stocker whistled like a SOB in my truck pulling a trailer. so much so people would roll their windows up as i would roll by them pulling hills. if i didnt love the sound so much i would have been highly annoyed by it 
my 475 was just a base model and it sang pretty loud though it had a short metal intake on it. the batmowheel added a bunch of whistle to the stock turbo. it was hard to tell what turbo was spooling when you wound them up
i have no idea what will increase or decrease the whistle, its litterally a 6"-8" long peice of metal pipe with the MAF in it and the straight coned filter off the end of it
I have a very short intake. And mine whistle loud enough for people to ask whats that sound.
Sent from my SAMSUNG-SGH-I537 using Tapatalk
Sent from my SAMSUNG-SGH-I537 using Tapatalk
Cast wheel in the 75 stock turbo is cast also. I have bigger piping than most twin kits. Its also all stainless but I dont know if any of that makes a difference.
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Sent from my SAMSUNG-SGH-I537 using Tapatalk
Billet wheels and race covers made no difference in my truck but they have all been pretty loud.
So in a s475 over stock setup it wouldn't do much for performance gains? It just makes it louder right?
No the opposite, you will see a gain from the right billet wheel, but the whistle is not louder, if anything it was quieter when I switched to a billet wheel.
Ok thanks, my mpi kit should be going on soon and I was wondering if it would be beneficial to upgrade the wheel.