i want boost...

[95TwinTT]

What is needed to run that S/C set-up besides duct work and mounting brackets?

What is needed besides duct work and brackets, is a way to control the fuel. I heard of some guys trying the system called “mega squirt”. It is a kit to make your own controller. They were not successful and ended up replacing it with FAST. Cost them an engine too.


I think it all depends on how far you are going to take the boost. If you are like every other red blooded male, you will not be satisfied for long with six pounds of boost.


Originally I used the Vortech injector block between the TBI and the stock manifold. After I rebuilt the engine, I wanted to have a system that I could control the injectors and advance. I picked up one of these setup’s. I used this with the Supercharger for a while including Nitrous. Now I use it with the Turbos. It can run everything from turning on additional fuel pumps to running the cooling fans.

http://www.electromotive-inc.com/mpi_kits.html

Whenever boost is introduced, the stock OEM is handicapped, because of no provision for going positive on manifold pressure. To do it right, some after market controller is probably needed.

If you have a good relationship with a Tuner and you have OBD-2, they may have found a way to read a 1 or 2 Bar MAP sensor. I just don’t know how far they have gotten, but that might be a way to deal with it.

You can spend money on labor for a “tuner” or hardware and do it yourself.

The good news about going to a aftermarket controller is that they can be moved from vehicle to vehicle.

There is always the “blow through” , carb. Then you only have to figure out the “jetting”. You just need good valves, and timing cotnrol with pressurized fuel air mixture in the intake.

There has to be a variety of manifolds floating around that have port fuel injection. I don’t think it has to be a marine unit. Lots of GM small blocks had them. Once you are set to deal with the stock size injector, then it is simple to acquire the right size injectors for the power range desired.

 

[tx tahoe z71]

Maybe, maybe not.

It is true that the Magnachargers are designed to make less power than the centrifugal superchargers. I believe that is because they are expected to be installed on “stock” engines that cannot take much boost because they are already at 9.5 – 10 to 1 compression.

You are not correct on the centrifugal S/C needing to be at higher RPM’s to make boost. I have 3 psi boost waiting outside the throttle plates at 1700 RPM’s on the highway. That is with the big mouth blow off valve open all the way.

You also mention having power all the way to 5500. Why not 6500 rpm? I have my WOT shift points set to 6500.

A proper installation of a centrifugal S/C has power right off an idle as does your Magnacharger.

As far as figuring how much power you will expect from 1 pound of boost. I was speaking in generalities expecting that you were already at 12 and heading to 15 psi boost. It can be figured by adding 7% to your existing HP. Here is how it goes.

If you have

200 hp + 1 lb = 14 additional hp
300 hp + 1 lb = 21 additional hp
400 hp + 1 lb = 28 additional hp
500 hp + 1 lb = 35 additional hp
600 hp + 1 lb = 42 additional hp
700 hp + 1 lb = 49 additional hp
800 hp + 1 lb = 56 additional hp
900 hp + 1 lb = 63 additional hp
1000 hp + 1 lb = 70 additional hp

As you can see, this is a progressive formula to be accurate.

As you know 15 psi boost is equal to double the atmospheric pressure, so another way to estimate power is to double the cubic inch estimate, so if you have a 350 cubic inch engine at 15psi boost, it should be at least equal to a 700 cubic inch N/A engine. Actually is should be more because is has the friction of the smaller motor and while putting out the power of the large engine.

As far as Turbo’s being high maintenance, you must be talking about a brand other than Banks. I have not touched my turbo’s since installing them almost three years ago now. I guess it makes a difference where you buy your Turbo’s.
And let’s not forget the Semi Trucks that go 500,000 miles on their turbo’s between rebuilds.

That Link you point to, is over 3 years old and seems to favor certain brands. There have been several improvements since then.

Before we get into a back and forth about which FI is better than the other, I am not a weekend racer, so am speaking from the standpoint of what I would want to drive on a daily basis, not at WOT flying down the 1/4 mile or around a track. My opinion is, that for a DD, a positive displacement blower has fulfilled everything I have asked for and more for my daily driven tahoe.

I cannot speak of hours or dyno testing or comparisons between s/c methods, but I can speak to where the power is made with the centrifugal style supercharged cars and trucks that I have driven, true they pull like hell after 3000 rpm, but before that, they felt about like they did before my friends put the s/c's on.

And why not 6500? Because in this case, it's my daily driver and I don't need to be spinning the engine that high to have fun. I barely ever go WOT anyways. I have a conservative shift point to reduce the risk of any failures, like a fuel pump going out or something like that.

When you are calculating your % above atmospheric, I agree with the thought process, however, as you compress air, you create heat. Your formula does not take into consideration the extra heat created by increasing the boost which, as a result, will decrease horsepower. In Radix applications, people going from 8 to 10 psi normally pick up about 40rwhp from the cases I have seen due to the added heat (predicted from above would be 56).

And aftermarket turbo applications, by and large, are more high maintenance than superchargers. A s/c can be put on by someone with limited mechanical experience in an afternoon with hand tools (ask me how I know). But a turbo system is usually going to require some cutting and welding to properly fit, as they rarely fit perfectly out of the box. You mention Banks, but as far as I know, they do diesel applications, not gas.

And if you are going to compare diesel engines (your semi truck and Banks references) and how they make power to gas engines, we might as well throw jet engines in there too, because we would be comparing apples to oranges either way. What works on a diesel will not necessarily give the same result on a gas, as you probably know.

And the link I posted is not the holy grail of FI information, but rather people's opinions who have owned both turbo and s/c vehicles and their experiences with them to help people decide. It is also to prevent the same questions of turbo or s/c, or centrifugal or roots, asked daily on the forum.

---------- Post added at 11:32 PM ---------- Previous post was at 11:26 PM ----------

For your intake pieces, check out this site... http://store.airflo.com/index.html. Look under intake tubing and rubber hoses and clamps.

 

[95TwinTT]

Before we get into a back and forth about which FI is better than the other, I am not a weekend racer, so am speaking from the standpoint of what I would want to drive on a daily basis, not at WOT flying down the 1/4 mile or around a track. My opinion is, that for a DD, a positive displacement blower has fulfilled everything I have asked for and more for my daily driven tahoe.

I cannot speak of hours or dyno testing or comparisons between s/c methods, but I can speak to where the power is made with the centrifugal style supercharged cars and trucks that I have driven, true they pull like hell after 3000 rpm, but before that, they felt about like they did before my friends put the s/c's on.

And why not 6500? Because in this case, it's my daily driver and I don't need to be spinning the engine that high to have fun. I barely ever go WOT anyways. I have a conservative shift point to reduce the risk of any failures, like a fuel pump going out or something like that.

When you are calculating your % above atmospheric, I agree with the thought process, however, as you compress air, you create heat. Your formula does not take into consideration the extra heat created by increasing the boost which, as a result, will decrease horsepower. In Radix applications, people going from 8 to 10 psi normally pick up about 40rwhp from the cases I have seen due to the added heat (predicted from above would be 56).

And aftermarket turbo applications, by and large, are more high maintenance than superchargers. A s/c can be put on by someone with limited mechanical experience in an afternoon with hand tools (ask me how I know). But a turbo system is usually going to require some cutting and welding to properly fit, as they rarely fit perfectly out of the box. You mention Banks, but as far as I know, they do diesel applications, not gas.

And if you are going to compare diesel engines (your semi truck and Banks references) and how they make power to gas engines, we might as well throw jet engines in there too, because we would be comparing apples to oranges either way. What works on a diesel will not necessarily give the same result on a gas, as you probably know.

And the link I posted is not the holy grail of FI information, but rather people's opinions who have owned both turbo and s/c vehicles and their experiences with them to help people decide. It is also to prevent the same questions of turbo or s/c, or centrifugal or roots, asked daily on the forum.

Thanks for the response..

Here is the link if you want to check out the twin turbo set up that Banks makes for GAS engines.

http://bankspower.com/products/show/267/85

By the way, there were no modifications needed to fit the twin turbo’s into the Tahoe, as in cutting holes in the body, etc.

As I have mentioned before, I’m not selling anything here. Just pointing out facts that can be verified easily if you do some checking.

Sounds like you are completely satisfied with your roots type charger. That’s great. I am totally happy with my DD even though it just has twin turbo’s.

My reference to Semi Turbo’s was to point out that turbo’s can go a long way without service. You seem to be under the impression that they are a constant hobby to keep them running. That might be true for a home made system.

Increasing boost obviously causes more heat, but we deal with it as it occurs. That is assumed in any serious boost application. The horsepower increases I mentioned, have been dyno proven. Not my idea, just passing that info along.

As far as you not ever seeing any noticeable power under 3,000 rpm’s on centrifugal blowers, I have never known anyone that had that problem. There has to be something wrong with the tune or something. It should JUMP off an idle. The average centrifugal blower impellor is already close to 10,000 rpm’s coming off an idle, if it’s setup right. I’m going to guess the blow off valve was not adjusted right, like maybe not closing quick enough.

I have two boost gauges in my Z-28, one in front of the throttle plates and one after. That is how I know I have 3 pounds of boost waiting outside the throttle plates when I’m on the highway at 1700 RPM’s. That pushes the air in quickly when the throttle is opened.

The first Vortech I installed was one of those weekend things with basic tools, nothing special. Even installing the twin turbo’s could have been done in one weekend, except for the exhaust.

Most of the people on this forum that want more power, want it for cheap. Anyone that asks me, I tell them it is not feasible to expect big power without spending money.

I personally don’t care what kind of F/I is used, but I think if someone goes to the extent of adding forced induction, they should know enough to not burn up their engine. I do believe that F/I is far easier to make power than nursing a small block to the high power numbers.

I rarely race my Tahoe. Once every two years or so is about normal. So it is a daily driver 99% of the time. My reference to 6500 rpm’s was to say, why go through the trouble of souping up an engine and then not take advantage of the higher rev’s to make it go. GM had the red line at 4600 rpm’s in 1995. That was the result of many years of trying to get mileage out of these heavy trucks. Then in 96, GM got their head out of their duffle bag and came out with the improved heads, that gave them 50 more horsepower for the same cubic inch displacement. Having an engine that makes big power, does not mean it has to get bad mileage.

You can believe what you have experienced, but I would suggest you keep an open mind and check out some of the new technology coming our way. Another source for Forced Induction is Nelson Racing. They make the entire package and set it up with it’s own engine management tuned and ready to go.
The sky is the limit.. Here is the link.


http://www.nelsonracingengines.com/