I have been a boost junky for the past couple of since back in 96 when i got a ride in a supra tt, althought I wanted one so badly, the prices skyrocketed after the f*ckin movie F&F came out, anyways i started out with a 94 325i and loved everything about it, the light weight, the handling etc, then i needed more and got the M-car. Now it's time for some F.I.

I don't want to spend over 10k for an F.I. set up including a the F.I. kit, clutch,flywheel, gauges etc.

My first choice would be BL but in all it would total way over 10k EASY. I originally wanted my M to out perform a supra seeing how monsters are coming out of ICS but my budget is tight. I want some crazy power but my wallets are stoppin me.

I want my car to produce around 350-400hp to the wheels. I looked into two good options. The TT turbo kit and the AA superchager kit.

Does AA make a kit with a bigger pulley, bigger injectors, etc.? ( I will be using a track pipe )

TT Turbo: Great Kit but what about turbo upgrades? Exhaust, etc?

Im looking to do this pretty soon and Im anxious to give my car more power, any help will be appreciated.

There's no comparison between a turbo and a CF SC. Anyone who says otherwise has a CF SC. :silly Been there, done that, sold it.

Boris

There's no comparison between a turbo and a CF SC. Anyone who says otherwise has a CF SC. :silly Been there, done that, sold it.

Boris

:( :bash: :(

Turbo. All day long...Its all about the torque....You do NOT want to do this twice. Turbo Turbo Turbo....Did I mention Turbo?

-Fred

PS. Turbo! :buttrock

Boris....besides the 6800 for the kit and the labor, what other necessary expenses did you run into? Considering BL's kit is 8g's shipped w/ great quality parts, im looking deeper into that...

Boris....besides the 6800 for the kit and the labor, what other necessary expenses did you run into? Considering BL's kit is 8g's shipped w/ great quality parts, im looking deeper into that...

No matter which kit you get you're looking at these expenses:

- Installation costs (DIY?)
- New clutch + Install costs (or DIY?)
- Boost controller (optional unless you don't want to vary your boost, but it's almost a must)
- At the very least a boost gauge

Basically all said and done you're close to your total. Figure a full exhaust + M50 manifold to get you to around ~385ish rwhp and you're right at your $10k mark.

Regarding the BL kit, the $8k is an introductory offer.. the normal price is $9k, but regardless... you're going to do your head gasket (more $ for install) so figure just getting the kit (at intro price) and having it installed $2k+ with head gasket you're already past your limit. Add in the clutch a must, boost controller, gauges, etc. I don't know how complete the BL kit is... how well it integrates (i.e. how much it can raise your install costs--exhaust isn't included, but does their basic kit include an exhaust to tie back into your stock exhaust or will your muffler shop be making that? etc.).

All hardware aside.... one of the biggest reasons: SOFTWARE! I'm still waiting for the price of Stage II which should be out pretty soon. It kind of helps because you have an upgrade path in the future, without having to go 'custom' or DIY route.

Boris

Turbo. All day long...Its all about the torque....You do NOT want to do this twice. Turbo Turbo Turbo....Did I mention Turbo?

-Fred

PS. Turbo! :buttrock
^^^^ i dont know whats better other then strapping a rocket to the back of your car

if you are truly a boost junky, then you gotta have turbo.

You gotta love TQ :buttrock

nothing like going sideways @80 right guys. :D

Getting away from my accurate, but neaderthal reply, Here is my rationale based on the science.

1. A centrifugal is basically 1/2 a turbo with a crank driven "turbo" rather than exhaust driven.
2. airflow out of the centrifugal type of compressor builds builds at greater than a 1:1 ratio with RPM. This is why max boost is at max RPM and generally 1/2 max boost at 1/2 max rpm.
3. The turbo compounds this by bolting a turbine section of similar design that causes even more non-linear increase in airflow with RPM. This is why turbos have wastegates to keep the boost from building to the point of blowing up the engine. This works to the advantage of the user as the boost builds faster and the wastegate holds at max boost(constant manifold pressure) until redline. This is why there is more "area under the curve" w.r.t. horsepower. Torque is MUCH higher because max boost is reach at a much lower RPM.
4. The turbo uses excess energy from the engine(in the form of exhaust heat) to power the turbo. The centrifugal is a parasitic drag on the engine's crank. This is why turbos are more efficient.
5. The centrifugal will have a more linear growth in power as it has a more linear application of boost. You won't feel that turbo kick. However, I don't think this is a big deal. The turbo does take a few thousand RPM to kick in in first gear. If you are really on the power and revving to 7K, the upshift will keep in the power and the boost is instantaneous. Thus the fully available torque and max boost make the engine feel Like a bigger and stronger motor. Even at hwy cruise speed, the boost is instantaneous when you stomp the throttle since the car cruises at 3500rpms at 80mph and the load on the engine in 5th gear helps the boost spool even faster. Remember the Centrifugal would be providing 3-4psi at this point, not the 8psi from the turbo.
Where the centrifugal makes sense is on very high torque motors that have trouble getting the power to the ground. ala built motor mustangs. If you have 400lb ft before the boost and expect 600-700hp and you wish to drag race on street tires, the smooth power adder of the centrifugal make more sense. The big pro-5.0 guys still use turbos because the max power is better.
6.
controllability. The turbo is controllable with an electronic boost controller. You can dial it down for day to day and dial it up for stoplight confontations or Racegas. To some degree you can dial in some smoothness of the boost coming on and program per gear boost levels in some controllers. Thus if you are traction limited in 1st gear you can dial less boost and have more in 2nd and even more in 3rd and above. Centrifugal cannot do that because the blower is driven from the crank. Any venting of intake air would throw off the MAF sensor.

Hope that helps

Thanks for all the replies as I will be going turbo anytime soon. It will be a hard decision to make. I do want the most bang for my buck but i'm hungry for power. The last post clarified alot of major thoughts in my head from s/c to turbo. With that being said, I'm looking to get atleast 400whp utilizing either a complete bolt on kit or custom. I do however have a question about software and the utilization of both 93 and race gas, will the software of a complete kit allow use of either 93 or race gas, and maybe a mixture of both? What size/trim turbo will help me push 400-600hp? I had a t-66 in mind but i question the clearance in the engine bay with the motor mounts and shock tower in mind. thanks for all the support so far -Ted

>>2. airflow out of the centrifugal type of compressor builds builds at greater than a 1:1 ratio with RPM. This is why max boost is at max RPM and generally 1/2 max boost at 1/2 max rpm<<

Thats not true. "1/2 max boost at 1/2 max rpm" is NOT what we experience on a CF blower. It is NOT a 1:1 ratio..What I mean is, while your statement about it being GREATER than a 1:1 ratio, so long as by greater you mean Squared IS true, whats NOT true is the second statement, about there being a 1/2 relationship wrt rpms and boost.. That would imply Linnear, whereas what we have with CF blowers is a Squared relationship.

For instance, if what you said were true, my engine which produces 11 psi at 7000 rpms would produce 5.5 psi at 3500 rpms.. Id love that to be true.. but its not... At 3500 rpms, Im making about 3.3 psi, the sq rt of 11psi.

>>
For instance, if what you said were true, my engine which produces 11 psi at 7000 rpms would produce 5.5 psi at 3500 rpms.. Id love that to be true.. but its not... At 3500 rpms, Im making about 3.3 psi, the sq rt of 11psi.

Thanks for the head's up, Paul. I have never had one and only know what I read/see. I thought the squared relationship was brought in because of the use of the turbine in the turbo, but I see that is not the case.

Software should support it as long as the mass air can support the max airflow into the engine. That being said, my guess is that the timing will continue to retard with more airflow. Thus you would want it added back in for more power on race gas, in theory. Others that do the software could answer better. Given your budget, I would recommend going with the head gasket and see which turbos others have used successfully.