Turbo Versus Roots Net Horsepower

[38flattie]

JH, you bring up very good points-thanks!

I'll be sure to take them into consideration, and plan accordingly!

[wheelrdealer]

JH

Good points, that turbo count on the salt will go up by one more in 2013. Thanks for all the great info. This question has been rolling around in my head for months. I now have a more clear understanding of the differences.

Bill

[jl222]

I'm looking for a little info. I've called several manufactures of 6-71 style blowers, and haven't received a definitive answer.

I know it takes HP to turn the blower-let's call that X. Just for the sake of this discussion, let's say X=100HP

The FlatCad made 570HP at 14.2lbs boost. If I took the blower off, and added a turbo, at 14.2 lbs boost would I then see that 100HP in my net numbers-670HP?

...or am I looking at this wrong?



Yes, I know the turbo isn't legal in Vintage class!

 38 flattie... it would be easier to answer your hp question if the intake charge temp was known but with no intercooling
or cooling from gas my charts show a 75-98 deg differance  over a 45% efficient roots type blower.
  Dyno videos are hard to tell if you had ice water circulating through intercooler.

  A couple reasons why we went with centrifugals over turbos over [20 yrs now] is that the centrifugals don't have instant
boost as the Turbo's did in those days allowing more throttle controll and less instant wheelspin Also keeping the fuel matched to the instant boost was harder to do then than now. New turbo controls and EFI have overcome those problems.

  In 1994 we had a time of 288 mph with a 279 mph exit speed. Overdrive trans clutch slipped, went back to dirrect drive
 engine went to 8500 dropped valve and blew one blower apart.

  We knew the combination was making good hp and despite having problems driving two blowers we have stuck with the centrifugals. Besides we like the sound [ some racers think we run fuel] Manufactures have finally
developed an independed drive for two blowers and in Pro Chargers case made blowers with enough CFM to only use one.

 Their are old Indy and Fuel injector guys [Gene Adams for one] that know what parts to use for the no electronics setup
for turbos and centrifugals.

                    JL222

  p.s. I have a Hillborn boost sensing device I'll contribute, if wanted

   

                           
 

[38flattie]

JL222,

We did have ice water in the cooler, but unfortunately, we didn't think about a port to take intake temps! We will next time, though! I'll run a dual chiller setup on the turbo engine, to get the cooling I need.

I fully understand why you went to centrifugals, and you sure as hell make HP-I should have that problem! Lol!

I really appreciate all the info on this thread, as it really helps me on this!

Oh, and the Hilborn sensor would be much appreciated!

[Jonny Hotnuts]

We did have ice water in the cooler, but unfortunately, we didn't think about a port to take intake temps! We will next time, though! I'll run a dual chiller setup on the turbo engine, to get the cooling I need.

I data log temps pre and post intercooler. In truth only temps out are important but its neat to see in and out. I run 10 gallons of ice water with high flow pump through a liquid to air IC. I could likely run >5 gallons as I have enough ice after a run to fill a chest.


Check out the boost controller made by NLR (AMS-1000). Its an expensive unit but with with a little tweaking allows the boost levels and ramps tailored to the weight and HP of the vehicle allowing you to accelerate as fast as your car will let you without blowing away the tires even with WOT. Plus the unit has an input that once activated goes to any pre determined boost level (almost like hitting a NOS switch!).

And the most important aspect of turbos.....chicks dig 'em.

~JH

[38flattie]

Thanks for all the advice and info! Johhny H, I'll be using that, or something similar.

Corky suggests we use the "Garrett 3582 series  looks like its best efficiency will be between 400 and 500 bhp (each).  The eff of 78/79% is terrific."

He is going to help us, and I'm going to try and enlist Hotrod's help, as he is knowledgeable, and close-'course, I still have to talk to him about it! Lol!

A member here on the board has a turbo and EFI that should work, so we'll explore that option too.I know the engine will make the HP-it's keeping it in one piece that I worry about!

[hotrod]

I will do what I can to help you out.

The Garret Gt35 turbos are very popular in the high performance turbocharged import community feeding displacements around 2 liters (122 cid - 152 CID max engine rpm in the 6000+ range). 500 hp at the crank is easy on that turbo even at this altitude in a serious engine build and a race tune.

That guy I mentioned who has a tuning shop and dyno near Longmont put a GT35R turbo on a subaru STi (2.5 liter) last summer and dynoed it at 510 wheel hp (corrected to sea level) here at this altitude. Using his normal correction factor that was around 433 hp at the wheels at this altitude on a street car tune.

Larry

[38flattie]

Very cool of you, Larry!

I'm sure I'll get to know you're buddy in Longmont well, as that's close!