Do I need Centri OR Roots !!!

[BeeDamn]

Hi guys there's some information is not really clear to me, so I need your help for that :)

I understand the diff between the tow, and I really liked the Centri one because of the HIGH end, In my country we don't have quarter mile, it's actually not limited in a street race !!!! so my Marauder is donin well in the first, second and third gearing. But in the fourth gear let's say about 120 mph or above the car fell sleeping and can't push it like the first or second gear !! it's not like not moving but really fell slow !! so my doubt is if I go ROOTs well I face the same problem !!? but what if I go Centri ? is it gonna become faster in the high RPM ? do I need to change or modified the Transmission ? please guys any info could be helpful.
The most important thing to me is the HIGH end speed !!!
I really don't understand why it's felt that SLOW !!

BTW my car has AEM filter, custom tune and a 3.73 gears ...

Thank you....



AZIZ

[Zack]

It not wise to go WOT in overdrive in these cars, due to the lack of strength in the trans.

Centri= High end
Roots= Low end

[BeeDamn]

It not wise to go WOT in overdrive in these cars, due to the lack of strength in the trans.

Centri= High end
Roots= Low end

I never went WOT in overdrive !!

I always turn the overdrive ON !! to safe the trans.

[BeeDamn]

Is it because of the gear ratio ? or the trans ?
I hope my question is clear to you guys ! sorry for my bad English...

[RubberCtyRauder]

The overdrive band can not take the the hard downshift from like 4th to 2nd when driving and step on the gas WOT is my understanding.

[Pat]

Replace your driveshaft with a metal matrix, stock not good for high speeds, above 144 kph, also get the transmission tail shaft lube kit. inexpensive and keeps the tail shaft bearings from seizing, a high speed requirement.

[djs2000mgm]

A well done roots setup will not lack high end, but it will also have low end torque. If you look at guys running tvs blowers or twin screws, you'll see that they're still making plenty of torque out to 6000+ rpm.

[BeeDamn]

So I need to change the Driveshaft and put the lube kit for high speed right ?

OK guys thanks, but still i don't get it why the car droped or sleep after the forth shifting !?

which mod is gonna make the HIGH RPM FASTER 100mph to MORE !! Centri S/C !!?

[BeeDamn]

A well done roots setup will not lack high end, but it will also have low end torque. If you look at guys running tvs blowers or twin screws, you'll see that they're still making plenty of torque out to 6000+ rpm.

So the Roots setup will not lack at high RPM !!? cool I really liked the roots type put i heared it's for LOW RPMs that's why I prefer the Centri one.

[Vortech347]

Well, what is your goal? Are you doing standing mile runs? or 1/4 mile runs? Once you get past 1/4 mile you open a whole new world.

[BeeDamn]

Well, what is your goal? Are you doing standing mile runs? or 1/4 mile runs? Once you get past 1/4 mile you open a whole new world.

I don't care about the 1/4 mile !! my goal is to get the Marauder to 140+mph as fast as I can :)

[clmrt]

Aerodynamics.

Drop the car 2". Make sure you have Z, W or Y rated tires.

Do you have a tune on it yet? You may be hitting a limiter.

According to an online calculator, the Marauder requires 245 hp to maintain 150 mph. Acceleration increases this requirement by a factor of 214468 x the speed of light.

[djs2000mgm]

So the Roots setup will not lack at high RPM !!? cool I really liked the roots type put i heared it's for LOW RPMs that's why I prefer the Centri one.

http://www.svtperformance.com/forums/showthread.php?920047-Just-installed-TVS-and-got-it-tuned-dynoed-today

Depends, do you consider 500 lb ft of torque at over 6000 rpm to be lacking?

[lji372]

Then bring a bag of money and buy my car.

BRING A BIG BAG :D

[MOTOWN]

You need a Centri for what you are attempting to achieve which is top end performance!

[Jeronimojc]

Do you have a tune on it yet? You may be hitting a limiter.



^^ You may be hitting a speed limiter at 120 mph.

Besides lowering the car and installing a centri, would changing gears back to 3.55 help him get higher top speeds?


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[99SVT]

OK guys thanks, but still i don't get it why the car droped or sleep after the forth shifting !?


If the car is shifting into fourth gear, that is the main problem. Forth won't handle that for long.
Change the gearing back to 3.55 or even 3.27 and add a supercharger. Then you can run out in 3rd gear.


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[Vortech347]

You'll need to have 3rd gear go up that high. If it requires different gears other than the factory 3.55's then consider a twin screw so that you can get enough torque to get the car moving at the lower speeds and top end power. A centri on a 3.55 or lower rear end is going to suck ass out of the hole.

Making this much metal accelerate quickly to 140 is going to take some serious cash.

[sailsmen]

Horse power wins races.
Torque wins race.

All depends on the type of race.

[justbob]

You need a six speed.

Done.


Self proclaimed Builder Of Badassery.

Buy it, Break it, Build it BETTER.
"Since 2004"

[BeeDamn]

Thank guys for the useful info,

So I need to get a 3.55 gears and a tune for now and then going Centri.

for my understanding if I want to achieve a HIGH RPMs going lower gear and going Centri, But if I want LOW RPMs I have to go higher gears and Roots IS THAT it !?

There is nothing in between !!? like balancing for the High and Low RPMs !!?

Please help me out guys I know I ask too much but It's seems that I don't get it right !! sorry guys.

[clmrt]

Engines have a power band - ours starts at 3000 rpm and maxes at 6500. Typically people will install a "stall converter" which allows the engine to rev higher before the transmission motivates the wheels - power band is reached before the engine bogs down, more acceleration off the line. It can also be made to "lock up" and deliver full engine power.

We are limited to three strong gears and a weak overdrive. Getting this car to live within the power band requires careful selection of gear ratios and transmission tuning.

I'm not sure how this will behave at the top end of a speed run. You'll need 500 hp on tap to break into the 140+ MPH zone, a transmission that can deliver the power without bottlenecking it, and a tune and gearset that will allow you to just enter the bottom 1/3rd of the power band in 4th gear.

[Green96]

First and second are a gear reduction at the transmission giving you the torque at the wheels (torque mahnification) to get the car going. Third gear should be your fastest gear. Fourth gear us actually a power reduction at the rear wheels. Without a supercharger you do not have to power to keep it going. Like I said 3rd should be fastest at least without a supercharger. Like the others said...do not let it shift into 4th at wide open throttle with or without a supercharger.

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[sailsmen]

Just do a top speed search;

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Quote:
Originally Posted by Peter
I'm planning on doing a list of modifications for my marauder, here they are:

Trilogy S/C
4:10 gears
Metal Matrix Driveshaft Dynotech
Addco Rear and fornt sway bar
Stainless steal break lines
PHP control arms
SS Inserts
TCE Breaks(both rear and front powder coated red)
And various stuff from Colex and Carmotorsports

Peter,
Just a couple of suggestions....
4:10s are personal taste, I prefer the 3:55s for top end, but went with a mild upgrade to 3:73s.

Skip the driveshaft, big waste of money. Just find a reputable shop that can high speed the aluminum driveshaft you already has. I have had mine up to over 165mph on a Nascar Oval track with my balanced shaft with no problems, will save a lot of money.

[BeeDamn]

Thats a usefull info I now understand it WELL

the 4th gear is won't handle that for long, i need to make my 3rd gear higher !!

I got confuse because I buy the car with 3.73 or 4.10 I think !!

could some body givin me a full chart of our gear and speeding !!

I need to know in stock gears 3.55 up to how much the 3rd gear can handle then shifting it to 4th gear

one more question do I gonna lose alot of LOW RPMs in the 3.55 gears ?

again and again I don't now how to thank you guys really I appreciated guys :)

[Vortech347]

Not a roots. A TWIN SCREW. There is a difference.

You need to be using online gear calculators to find out what gear you need for your desired RPM/Speed. You don't need a chart.

3rd gear is 1:1. DO NOT USE 4th gear as a power gear. Not only will you blow the bands on the transmission it will have to much load because of the overdrive the engine will create a ton of heat, detonation and BOOM!!!

As someone else mentioned a manual transmission would be much better suited. You're asking questions few can afford $$$ the answers to..

[99SVT]

3.55 at 6000rpm top speed in 3rd is 139.5mph
3.73 is 132.8mph
3.31 is 149.6mph

Another option is to raise the redline to 6500 or 7000 if the engine is built with parts to handle it. I can run my car up to 140mph in 3rd at 7000rpm with 4.10 gears, but the engine is built to handle it.


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[tbone]

You didn't answer the most important question. Do you have a tune with the speed limiter turned off? If not, you're questions and solutions offered won't make any difference.

[BeeDamn]

Thank you guys now I have to change my goal I figured it out that a lot of info that I didn't know or I was miss understand some info, Thank you guys

[BeeDamn]

You didn't answer the most important question. Do you have a tune with the speed limiter turned off? If not, you're questions and solutions offered won't make any difference.

Yes sir I buy the car with a Tune and 3.73 gear as the previous owner said

[tbone]

Did you get a tuner or did he just say it was "tuned". Sounds like you don't have it and don't know if the speed limiter is turned on. Probably is.

[BeeDamn]

you probably right I'm not quiet sure if it's tuned but the gear shifting and the speedo meter error seems like it's already has a tune !! how to figured it out that my car already have a tune or not !!?
and BTW I was mistaken in going WOT with O/D on !! I just now realize avoiding shifting to the 4th gear, that's why i said i fell the car sleepin !!