T0S

I see Pettit and RX7store have a "stage 1" upgrade package with a cold air intake, cat-back and unorthodox pulleys that claims to add 60 hp. Can anyone with these upgrade attest to this power bump? I'm at 5000ft and am wondering if that'll make a diifferece.

JoeD

im gonna say that at your altitude and stock boost levels, 280 RWHP will be impossible. your gonna have to throw in a new ECU, downpipe, and up the boost to 12 PSI. then, 280 RWHP should come by with ease.

T0S

Thanks.
Has anyone verified the claimed +60HP at sea level, though?

Also, any input on the Apex Power intake/N1 vs. the Pettit racing TKT kit.

Mahjik

iTrader: (1)

I would imagine that Pettit has verified their own claims. They are a pretty reputable shop.

As far as the Apexi Intake verses the Pettit TKT Intake... The Pettit intake is a cold air intake while the Apexi Intake is an open air intake (which means it can bring in hot/warm air from the engine). Colder air is always better given the choice.

JoeD

yeah, but the Apex intakes have been proven to be the best intakes in the world.

potatobbq

... but not necessarily on every car. on an otherwise stock fd, i think the cold air intakes by m2, pettit, cwc, etc. will work better. if you have an upgraded ic, etc., running an open intake like the apexi intake might be better. anyone out there want to make a heatshield for the apexi intake? of all the open intakes tho, i do like the apexi ones best.

the_glass_man

iTrader: (2)

This is going a little overboard, don't you think?

JoeD

there was this one website that tested and compared a K&N filter, Blitz sus, Apex, and GReddy, and the Apex came out on top.

it gave the most flow, most power, and cleaned the best. it won....BY FAR!ill search for the link.

BTW, im talking about the filters alone, not the entire intake setup.

the_glass_man

iTrader: (2)

I know of the link, I was just reffering to the filters themselves. How many guys in F1 or Cart use A'pexi filters?

JoeD

JoeD

here is the link.

http://www.gtrowner.com/induction.html

the_glass_man

iTrader: (2)

I'm not sure if those are the best real life test conditions, also I own a FD not a Skyline (I wish), plus its in pig latin or something (price and such) so it can't be true!
I have a page that proves that no filter is the best way to go! Super clean and more power, plus you never have to replace a filter! Just replace your turbos or your engine.:p

BlackR1

do the guys in CART and F1 even use filters??

JoeD

yeah...thats really smart!

kwikrx7

60 hp seems a little optimistic to me for the intake, pulley and catback. I would say around 15 hp for each but every FD is different. I remember someone doing a test on their FD with the base package (cb, intake, pulley) and having 311 flywheel hp so maybe it is close.

Jason

iTrader: (5)

My car put down 272 RWHP with the intake, exhaust and Pulley. Every car is different so H.P. will vary. It also depends on which products you use. Some yield more H.P. than others.

Jason
www.rx7store.net

kevinmfaust

The Pettit intake is a poor excuse for craftsmanship........I mean POOR. The EGR dog farts every time you let off the gas because there is no box to vent it in to kill the sound. The system looks and fits like some blind one arm guy built it with out any tools. Check out the M2 cold air box set up befor you buy.......I wish I did.
Kevin

altrdego

Ok it's an issue I've wondered about....

Atmospheric pressure

at altitude the air is a little thinner... less atmospheric pressure.

We take the thin air and boost it to 10, 12, 15 or whatever PSI. Maybe it takes a fraction of a second more to gather enough air to boost to pressure.

Why does it matter if it's at altitude or not. Isn't 10 PSI at altitude the same as 10 PSI at sea level?

The good think about altitude and low pressure... It's less the car has to push against. From someone at about 1,000 feet above sea level.

Any experts or anyone else care to express their views?

Merciless

+60hp at the flywheel..not to the rear wheel...

JoeD

becasue that 10 psi is a lot thinner and less dense than 10 psi at seal level.

T0S

Guys, as the original poster - thanks for the responses.

A couple of points about altitude. First, 10 psi is 10 psi regardless of if the air is "thin" or not (remember the trick question - what's heavier 10lb of cotton or 10lb of iron).

Secondly, the real question is does the RX7 control to 10 psi absolute (not delta to atmosphere)? I believe so. So, as long the air is "thick" enough to allow the turbos to deliver 10psi I'm all set. In fact I'm much better off than normally aspirated cars which suffer dramatic power loss, uncompensated by turbo pressure control - my neighbour's Viper feels less strong than my stock FD.

Still, given that at altitude the car does not pull in air as quickly as at sea level is was wondering if the +60 flyHP was still on.

jasonsr1

When one speaks of 10 psi of boost pressure or reads 10 psi on a boost gage, what is actually being read is 10 psig or 10 pounds per square inch gage pressure. The actual pressure or absolute pressure is Pa = Pambient + Pgage. At sea level ambient pressure is about 14.7 psi. For the above scenario Pa = 24.7 psia.
As the altitude increases Pambient decreases reducing the density of the air. The compressor has to do more work to the air to obtain 10 psig and thus takes longer to obtain that pressure.

The key concept to understand is that regardless of atmospheric pressure or temperature, 10 psig (gage pressure) of air has a particular density, so in order to obtain that density it makes sense that if you start out with relatively dense air, it will take that much less energy and time to obtain 10 psig then if you started with low density or low pressure ambient air. In addition to ambient air pressure, the rate of pressure rise is a function of volumetric flow rate which is a function of port size, turbine size and shape, etc...

To summarize, the denser the air entering the turbos the more efficient the compression process and faster pressure rise.

luneytune

Your compression ratio of the engine at sea level is the same as at 10,000ft. 9:1 less dense air means your absolute density after compression is much less and you then are adding your 10PSIG to that = less power at altitude. But less pinging!