Forced Induction

[Ender2664]

I have no idea about this whole gas milage thing, but if you drive your car on the freeway for 100 mile and use cruise controll and with and without the turbo, that should settle the debate on freeway, i know around the street it is much more complicated than that.
But as for spooling i would have to say that you are way off. I am friends with alot of Turbo people from hondas to eclipses to supras to skylines and based on when there turbos spool and the size of our engines i would have to say that we could spool up a small turbo in the low 2s and high 1s, and a medium turbo at mid 2s and a BIG turbo at 3!

[T-Punk]

the gass mileage is simple, with the turbo you get similar mileage untill you come under boost. this has been proven by everyone who has a turbo, pure and simple they all have lost mileage under boost and have had about the same when not running boost. now as for the spool, there are several reasons your friends with those other cars can probably spool earlier. for one they could have more efficient ball bearing turbos, another thing is that because of how all of the turbos systems with our cars have been made (except shanes system) the exhaust hast to tavle such a long distance and have to fill so much piping before they reach the turbo and also because of this the exhaust gasses also have time to cool (thus becoming less denses, and not moving as quickly), so far the systems made have spooled between the mid 2000 and low 3000rpms (this is from actual people using turbos on OUR cars). now when i get done with my twin vnt setup yes spool will basically be non existant do to being mounted in the optimal location, and the special characteristics of these turbos to be more efficient throughout all rpm ranges.

[Ender2664]

I am fully aware of how the systems are set up, and we took that into account, and i wasn't talking about the turbos that come with the kits, i was talking about good turbos with a good size exhaust housing.

[T-Punk]

Ok, how small of a turbo are you talking about spooling in the low 2 range? to me one that spools that soon will not offer optimal gains and will add a ton of backpressure. if you think a t3/t4 will spool in the mid 2's to 3000rpm then i am in agreance with you. a t4 should be in the low 3's (assuming piping similar to the kits are used). the only ways to use less piping and get optimal efficiency from the turbo(s) is to go twin or make forward swept headers.

[nocutt]

you stay away from boost on the freeway for a 100 miles MPG WILL BE close to and even maybe better than stock because the driving characteristics are consistent and the engine with 9.4:1 CR with a turbo 'doesn't feel' like working for air...that is a given, but we aren't been simplistic here...in the real world with all the scenarios...you WILL LOOSE MPG...period!! we can leave it there!!
As already mention by T-punk, spool characteristic is based on a lot of variables, however the chunk comes from exhaust A/R...primarily, then comp housing...then wheels...then piping...stc, the idea is really complicated when trying to quantify...however staying with the consensus! generally a bigger A/R housing will create the 'subjective lag' or spool characteristics!

[Radcat]

Before turbo
city 18-20mpg highway 24-26mpg
after turbo
city 19-21mpg highway 28mpg

This was when I still had the stock fuel pump with an inline fuel pump and injectors with no tuning. I was also running 10psi but driving like my grandma. I still got on it a few times though.

[CM boyd]

Hey guys, has anybody everthought of eliminating
or offsetting the mechanical loss of the supercharger belt by adding an electric waterpump
to our cars? Merize (how do you spell it) water
pumps are sold by ZZP Performance. Claims up to
7HP gain throughout the RMP range by not having the belt route through the standard setup. I am
curious because I know it works good on NA vehicles. I am unaware of the horsepower requirements to power the supercharger belt. Any
one guess how much it takes?

[GN-T66]

Originally posted by CM boyd:
Hey guys, has anybody everthought of eliminating
or offsetting the mechanical loss of the supercharger belt by adding an electric waterpump
to our cars? Merize (how do you spell it) water
pumps are sold by ZZP Performance. Claims up to
7HP gain throughout the RMP range by not having the belt route through the standard setup. I am
curious because I know it works good on NA vehicles. I am unaware of the horsepower requirements to power the supercharger belt. Any
one guess how much it takes?

depends on boost level. 30-50hp on these motors at common boost levels.

[Mighty Thor]

Originally posted by T-Punk:
FORCED INDUCTION

From what I have found typically if you have a supercharger it takes 100 hp to run but produces 200 hp, so after you take the 100hp from the 200hp the SC added your gain at the wheels is only 100hp (still very impressive).

That is very false. You got that example from our tech page. It was base on a gross exaggeration of what a parasitic lost is.

I could make my SC pulley rotate with my hand and it will make a couple of revolution, it doesn't lose that tremendous amount of HP.

Other than that. That's pretty good. ;)

[nocutt]

Thor,
The loss on the SC is definately not linear...I am sure we can all agree to that...but you are right...it is also exaggerated ans sometimes taken out of context...

Cmboyd...
IMHO I don't think a street car should use an electric water pump...but that is just me, I have not seen one that will outflow a stock unit when you really need it...if one lives his life in the 1/4 mile where you turn the car on, race cooldown and then shut-off by all means...but with cars needing to be in the 200* range...I don't see the benefits...at least not from where I stand...

[Turbo V6 Camaro]

:eek: :eek: holly hell a clean debate :D :D keep is comeing guys
edit: already stickied [img]graemlins/slap.gif[/img] ;p;

[ January 11, 2005, 09:36 AM: Message edited by: viper04af ]

[oil pan 4]

Remember that 35% of the energy from the gas you burn is blown out the exhasut.
It is because of 2 reasons, one the exhasut is real hot. 2 the exhasut valve is opened well before BDC on the power stroke.
That does 2 things it lets the exploding hot gas blow its self out the exhasut for good scavenging and that increases power while droping engines efficiency.
On a real turbo system where heat and exhaust gas scavenging pluses drive the turbo while cruseing down the road the turbo should beable to convert some of that 35% in to mechanical energy (turbine) and push some air into the engine boosting it's efficency.
You can also get better gas milage running high compression a small cam with less timeing. That does some of the same things a turbo does. High compression (with a small cam) scavenging is better, the chamber fills better (there is less chamber vol causes more vacuum that fills the cyl's better) and lets you run less timeing.
On a diesel a turbo boosts fuel efficiency. I have posted the reason before and went some thing like, adding a few psi to the intake charge when putting a load on a turbo diesel raises dynamic C/R and burns stuff that would be truned into black smoke and soot on a N/A diesel.
On a gas engine there are more factors that a diesel just dosen't have.
If you want to run a electric water pump on the street you might need a bigger Radiator and different thermostat with a hole or 2 drilled in it.

[oil pan 4]

I was talking about Cruising going up a slight hill at most, not full power.

[Turbo V6 Camaro]

Originally posted by Radcat:
Before turbo
city 18-20mpg highway 24-26mpg
after turbo
city 19-21mpg highway 28mpg

This was when I still had the stock fuel pump with an inline fuel pump and injectors with no tuning. I was also running 10psi but driving like my grandma. I still got on it a few times though.

i knew you said that long as kept your foot out of it you got better milage....

[CM boyd]

I have not heard too many alternate views concerning the electric waterpump for the 3800SII
engine. But I do like to keep the engine as far
below the 200-210 degree temp that is stock. Is
it a fact that the shorter the belt routes around the engine, the less pulleys it drives, the more
power gets put to the ground? I kinda had a haunch that the supercharger pulley was not that
hard to spin anyway. That claimed HP gain was
said to be gained at the wheels too. I saw a website where some guy with a stock v6 ran in the
14's because he took his serpentine belt off! I
want to try the electric water pump and see how
well it will compliment my turbo setup.