which induction piece
this is the volant setup
http://www.lmperformance.com/2386/1.html
The FTRA will get air from underneath the car(away from engine heat) and send it directly to the air box...
<strong> I think that you will see the best gains with the lid/FTRA. It looks like the volant set-up uses the factory SS hood. The ram-air hood on an SS is very inefficient, mainly because there is alot of heatsoak on the hood from the engine heat and the air actually has to back track in the hood before it gets to the airbox.
The FTRA will get air from underneath the car[away from engine heat] and send it directly to the air box... </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Not sure I agree with the heat soak bit.
Maybe if it sits a long time. In normal
around-town cruising I read IAT temps
at 2 degF above outside air (per the time/temp
signs by the Walgreens). On hot starts I
can be seeing up to 20 degrees above outside
and it takes a long while to come down.
Whether this is heat soak in the plenum, or
heat soak on the airbox and IAT sensor, I
couldn't say. I guess maybe leaving the hood
up while waiting for the next pass is a good
measure. The outside of the hood stays pretty
cool even after a long hard drive, the material
does not have much specific heat or thermal
conductivity so I don't think that heat transfer
to the airstream is a very substantial issue.
I think if you didn't get it for "free" the
SS hood isn't worth the money per performance,
compared to the other induction mods. But
I also find that [at least on the highway]
I have 14.2-14.4PSI MAP readings at 6KRPM
WOT, out of 14.8 ambient. So if there's a
restriction, it's like <4% short of ideal over
the whole intake tract. I relooked at this
after doing a FRA-ish mod [cut the airbox
bottom, blocked off the radiator air, extra
air comes up from before the radiator shroud
through an additional ~1/2" x 12" slot].
No improvement in MAP, +/- 0.1PSI. So I
don't think the SS hood is any kind of inlet
restriction, on my ported-TB, 85mm MAF, lid
and SS-hood car, because doubling the airbox
inlet area and bypassing the hood did nothing
measurable.
I came across a good tech article on www.installuniversity.com about SS hood efficiency. The article might demonstrate what I was trying to say about heatsoak into the hood.
"The IATs were around 115 °F when we first started the testing. Once the car had been in motion for a mile or two the IATs dropped into the middle to low 90 °F. Wow! I knew that it just didn't get cooler outside all of a sudden! So what would cause this phenomenon to happen?"
"That gave me the perfect hypothesis that needed to be tested. While your car sits at idle the engine temperature rises. The hood soaks up the heat and can not dissipate the heat quick enough to stay cool. This causes the air that passes through the SS hood to soak up the heat from the hood. By the time the air gets to the air box you have heated air. Once the car goes into motion the hood is able to dissipate the heat to the outside air fast enough to lower the temperature of the hood. This would cause the air that enters the hood scoop not to heat up quite as much which would keep the air cooler"





