i want boost...

[DJTricky]

so its settled i think im gonna be going turbo. im gonna be meeting up with 95twintt this weekend so we will be talking some info.

 

[Rollin Thunder]

IM gunna go turbo to. Turbo diesel that is. bow chicha bow wow.

 

[DJTricky]

well i know there is alot of stuff that i start thinking about doing and well so far this is one of the ones im really thinking about so....

i bought this.





me and my buddy are wondering how much the stock internals can handle. cus now he wants to boost also(he wants to beat me) how many psi can stock handle?

 

[bai78]

Size of said turbo?

 

[DJTricky]

its a t3/t4 55 trim A/R .50

 

[tx tahoe z71]

A turbo is going to be a much higher maintenance setup, that's why I went with a blower, bolt it on and forget about it.

And with the boost bypass valve on the Magnachargers, when you're not in boost, there is barely any parasitic loss, my MPG actually went up with the addition of my s/c, I get 15 in the city and 21 on the highway now.

And 1 pound of boost is equal to about 15 (not 50) horsepower, to correct an earlier statement. If that were the case, my 8psi blower would have put my tahoe from 256rwhp to 656rwhp, lol.

My Magnacharger makes boost starting at about 2300rpm, so if you are making a daily driver, a blower will be much more fun. A centrifugal type supercharger will be a fun highway screamer, but won't make much below 3000rpm, so probably not as fun of a daily driver.

And yes, a turbo setup has the potential to make more power, but you have to consider where all of that power is. With a roots type blower, it will be pretty much off idle all the way up to 5500rpm. A turbo might start at 3000rpm, but then take off pretty steep from there. For a heavy a$$ truck or suv, you need low end torque to get you off the line (and make it fun), but put a high stall converter on a turbo setup, and you're good to go, probably lose some mpg in the city and make it somewhat annoying to drive, but it will fly once you get on the gas.

So to answer your question about turbo vs sc, it's all about what you want out of it. Just my 2 cents

---------- Post added at 11:07 AM ---------- Previous post was at 11:03 AM ----------

Actually, just skip my post above and just read this: Link

Pretty much every question answered

 

[95TwinTT]

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.

 

[bai78]

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

How is this achieved? Mine, according to the dyno runs, kicks in around 2500 at WOT.

I have tinkered with the idea of swapping out a smaller pulley. Right now it is a 3.5" and according to the formula ProCharger provides a 3.2" would be the smallest I could go without pushing the limit specs of the P1SC. It is rated up to 30 psi, 62,000 impeller rpm, & max cfm flow of 1200.

Impeller RPM = (N1/N2) * (4.10) * engine RPM

N1 = crankshaft pulley diameter of 8.00"
N2 = supercharger pulley diameter of 3.5"

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

I absolutely agree that about 98% of pt.net is favoring MagnaCharger. They are extremely sceptical of the new Vortech twin screw blower. There are a decent amount of ProCharger guys on there but they are biased as well because the majority of them run D1SC and kinda look down on us P1SC guys.

 

[95TwinTT]

How is this achieved? Mine, according to the dyno runs, kicks in around 2500 at WOT.
QUOTE]



I’m not familiar with the ProCharger. I’ll just explain what I went through with my Vortech. The original kit, came with two injectors that were in a block that went between the TBI and the intake. It was controlled by a black box, looking at intake pressure.

The system came with a 3.33 inch diameter pulley on the blower. Crank pulley I believe was 8”. The 95 Tahoe was a slug from the factory. This kit made it come alive. The gas pedal was all of a sudden extremely sensitive. It just jumped off an idle. I drove it like that for about a year, loving every minute of it. Then I started noticing oil leaks. Turns out the increasing blow-by was causing enough positive crank case pressure that things that would normally not leak, were leaking.

I decided to just pull the engine and fix whatever it needed. I found the stock pistons and rings, were not real happy about having a blower leaning on them. Since I am into the “might as well” syndrome, I dropped the engine off at my favorite engine builder and said, make it tuff.

That’s when the AFR heads and custom pistons and cam came in. When it was back together again, I decided to up the boost. I went down to the 2.75” pulley.

Now I was reaching 15 psi boost. The 3.33 pulley would top out at maybe 10 psi. The blower spec’s say it can do 20 psi boost and 1,000 CFM @ 50,000 rpm max.

I have been pushing it way beyond the 50,000 rpm’s. That worked just fine for a long time, until I discovered the Vortech getting noisy. I sent it to the factory. Next I got a call from the technician working on it. He asked how cold it was where I was? I said, depends, but it was about 10 degrees that day. He said, you can’t run the SQ (super quiet) in cold weather. So he rebuilt it with the straight gears, like the T trim has and no problems after that, but it had that significant whine you get from the straight cut gears.

This is from Vortech’s web site. They list their pulley sizes as 3.33” 3.12” 2.95” and 2.75”. Then they go on to say, “A change in 1 pulley size will usually effect boost 1 – 2 PSIG…… Down in diameter, up in Boost and Vise Versa”.

I certainly found that to be true. I guess I would say, you should see noticeable power coming off idle. The dyno run’s generally start around 3,000 rpm’s, so that doesn’t mean much for the low end. They take a few hundred rpm’s to establish the load against the engine before they are reading right. My dyno sheets are almost horizontal lines after it gets up to speed.

I would not hesitate to go down a size in pulley size, if for no other reason, than, you cannot be getting close to 62,000 rpm,s the way it is. Plus 99% of driving is just normal cruising, so it certainly won’t hurt the S/C at all, even if you were able to get it over 62,000 once in a while.

The only concern to me would be your “tune”. Were there additional injectors included with your system, to compensate for what the blower was adding?

That would definitely get it moving off the idle is you don’t think it is enough now. The other thing is, if you still have the stock piston rings and all, expect a sooner visit to the parts store for new pistons and rings, relative to how much more you up the boost.

You may also be up against octane issues too. I’m running 92 octane all the time with alcohol injection when under boost, starting at 5 psi.

I also want to go back to my original kit for a moment, I noticed a hell of a change in power with the original 3.33” pulley and no alcohol on a stock engine.

The specs on your ProCharger are higher and more impressive, than my S-Trim. It would seem like it would be doing the job and then some

 

[foreverfalcon40]

If any of you mofos selling your S/C kit for a turbo pm me!