Rotr8

iTrader: (2)

Both are pretty smooth with nice power coming on quicker than the feel in an NA , the TC car Ive been in I would describe as a little bit more raw in that when it hit boost it kicked ya in the but, the SC that we drive in here has that warp drive feel with the power feeling coming higher in the RPM range, I would say the TC gives you a torqier feeling,,,
Sorry I got distacted in your other thread by someone trying to describe the feeling without being in either,,,

mac11

iTrader: (1)

you and your fancy "books". get a clue buddy.

california style

yeah I've been in a couple of Turbo 8s and a couple of Pettit SC ones.

On a track day I was driving a SC car and rode in a Greddy turbo one.

The Greddy install was hell though with heat soak making it like driving in a sauna! I actually felt sick after 2 laps.

The Greddy owner rode in mine and said he felt it was pulling better than his car, but without longer comparisons actually driving the cars, I cant say much more. He said he lost power quickly due to heat issues.

I do love my SC car though, in my opinion it's like a perfect RX8 now!
Unfortunately, someone rear ended me, so its in the garage, and I'm missing it a lot!!!! BOOO!

Rote8

The S/C torque curve is flat, almost a table top.
This means it moves from the low end of the curve to the high end very easily.

And the "SC takes 30 to 40 HP"; two things to remember:
(I think some people already knew them too)
The Lysholm blower is a small twisted screw type, running close to it's sweet spot for efficiency, not the large 8-71 Roots type blower used for your "30 to 40 HP" calculation.
I expect the Pettit blower to draw less than 15 to 20 HP, even when spinning under load at 16,000 RPM.
The bypass valve opens when the engine does not need boost, when fully open, the S/C is free from load uses less than 3/4 HP to turn the screws.

There is no free lunch with boost verses sacrificial power loss, a theoretical Turbonique style "rocket powered" turbo configuration, to completely remove the exhaust restriction caused by the turbo's impeller, would get back more than "6 to 10" HP. (Turbonique was awesome in the early 60s)

As for which is better; S/C or Turbo?
I say, boosted is better than N/A any day.

Rote8

I hope everyone had anti-freeze in any liquid to air inter coolers last night.
I forgot; I had to remove some water, add anti-freeze and recirculate for 20 minutes after dark last night.

morkusyambo

I would like to see where you have documented how it uses 40-50hp at max load. If you have allready posted it somewhere before, would you mind directing me to that particular thread?

morkusyambo

Well said. Regardless of what route you choose, there is allways some sort of compromise. Where do you want your restriction, intake or exhaust? Do you want higher peak #/s, or a torque curve as flat as a table from 0-redline?? Bottom line is both are enjoyable.

Now, rx8thunder, please keep the TC vs. SC conversation in its proper thread. It has been done to death over here.

Thanks. -Yambo.

morkusyambo

Awesome! Not bad for "only" 8lbs of boost. Where will you get the injectors from?

-Yambo

Bastage

iTrader: (1)

It's documented in his colon. You'd need a flashlight, and a full hazmat suit to see it.

Seriously. I want to see Norm's car on a dyno. He did something to it, and it's just sick now.

california style

yeah 369 is mental!

morkusyambo

I think I know what he did.

olddragger

iTrader: (3)

on track the s.c. can get great performance with a adverage lower rpm . i rarely go over 7.5K on the car. less rpm's means less heat which is good for all. Also less strain on drivetrain. It suits me fine--turbo's are great just a little differant animal.
You would have to set the boost properly so the power delivery would be smooth
"power "kicks" on the track is not a good idea.
OD

Brettus

iTrader: (2)

Tend to agree with you about the power "kick" being a bad thing on the track with a turbo. I'll be starting my learning curve on that next week .
As far as heat soak mentioned above goes i think that would come down to how the turbo is set up . I am thinking a lot of early turbo users ran at lower pressures and high rpm which is counter productive for heat soak issues as it puts the turbo well outside its efficiency curve . (yes- i just learned this)

Red Devil

That's it you're fired from being project photographer, and back to being parts monkey.

Rotr8

iTrader: (2)

Idont think I was told what he did ,,, i cant say , but I cant wiat for mine to be able to do that either,,,,

rx8thunder

Thanks for the feedback guys. I do get that there is no perfect option. I am very encouraged about what I hear about the SC in terms of it's unique characteristics. I also found this post on Yahoo! interesting...


"Either choice is good depending on how you want to change the engine characteristics.

Turbo's can give the Renesis more overall HP and torque, but the power will be "peaky". You will gain little in the lower RPM band, have a huge spike of power in the middle band, and then die off around 6500 - 7000 RPM. This is because the turbo won't respond and give any appreciable boost until 3K - 4K RPM...completely normal for a turbo. Then the turbo will be able to create large airflow, but only up to perhaps 6K RPM where it will be producing its maximum flow. Then power drops off as you have the same airmass but the higher RPM's mean less shared air available per combustion cycle.

This is too bad as the motor runs to 9K+ RPM and the tertiary intake ports don't even open until 7200 RPM.

You can get turbo's that can flow enough air to allow proper chamber filling at the higher RPM's, but they'll take longer to respond and boost may not appear until 5-6K RPM.

The superchargers designed for the RX8 have been designed with the extended RPM range of the Renesis in mind. You'll have a better low end as they produce boost all the time, just not as much low down as it's not spinning as fast, and the airflow can keep increasing with RPM right up to 9K. But you won't get as much mid-range power as the turbo as boost & airmass is related to RPM.

So the turbo will give you more total HP, mainly in the middle RPM band and change the way power is delivered. The SC will give a lower overall power increase, but it will be distributed more evenly across the RPM band and the motor's response will feel much the same as now, just with more grunt everywhere."

Kane

iTrader: (1)

That information is actually incorrect - but whatever.

If you are leaning SC; then go with it - I bet you will be perfectly happy.
If you are leaning turbo; get the right size and go with it - I bet you will be perfectly happy.

If you think one is superior to another - great; go with it...

If you want to know more about Forced Induction; then do the legwork. But honestly for a street driven car; within +-30 HP; I bet they feel pretty much the same.

morkusyambo

If he did what i think, you don't think you were told but cant' say, I may have allready done......then he will definately need larger injectors.

morkusyambo

That is what we have been trying to tell him. Again, rx8thunder, we're all glad you will be going FI and will help you if you need it, but there are plenty of other threads dedicated to this topic. Please post your turbo questions there.

-Yambo

MazdaManiac

iTrader: (3)

Does anyone ever actually read the stuff that is already up here about how this stuff actually works?

Just looking at the "Dyno Comparison" should be adequate in dispelling junk like this.

Moon Assad

1.5 HP at idle, hmm, guess you forgot to pull the spring out of the bypass valve. ??? what engine number are you on, was it 5 or correct me if im wrong or was it 6, not bad, thats almost a motor or 2 a year, good thing you can get parts so cheap.

Red Devil

I have documentation on Lysholm units. They typically draw 5hp more than the Autorotor ones. Off the top of my head the RX-8 draw from Lysholm was around 30hp at 8psi.

Brettus

iTrader: (2)

here we go ......................

Kane

iTrader: (1)

Do Until [Tired of BS] = "yes"
Call SC_is_mo_better_science()
If Postcount On Subject < 100 Then [Tired of BS] = "no" Else [Tired of BS] = "yes" End If
Call TC_is_mo_better_science()
If Postcount On Subject < 100 Then [Tired of BS] = "no" Else [Tired of BS] = "yes" End If
Call not_ugh()
If Postcount On Subject < 100 Then [Tired of BS] = "no" Else [Tired of BS] = "yes" End If
Call uhh_huh()
If Postcount On Subject < 100 Then [Tired of BS] = "no" Else [Tired of BS] = "yes" End If
Call various_dyno_proof()
If Postcount On Subject < 100 Then [Tired of BS] = "no" Else [Tired of BS] = "yes" End If
Call various_dyno_rebuttals()
If Postcount On Subject < 100 Then [Tired of BS] = "no" Else [Tired of BS] = "yes" End If
Call circular_logic()
If Postcount On Subject < 100 Then [Tired of BS] = "no" Else [Tired of BS] = "yes" End If
Call other_poster_is_a_poo_poo_head_and_fanboi()
If Postcount On Subject < 100 Then [Tired of BS] = "no" Else [Tired of BS] = "yes" End If
Loop


There - just run this little program to find out what happens.

Brettus

iTrader: (2)

can "poo poo head" really be used in programing terminology ?