said the salesman.... j/k

ive been thinking of a wastegated centrifugal blower for my comet. and id just like to add that PSI is not the way you measure power potential in a blower. its the airflow. some of these blowers can flow the same airflow at 14psi as they can 20, you just need the motor to be able to huff all that air in then you get lower temps and all that wonderful crap along with it.

 

The Eaton M62 and the Lysolm Twin Screw both flow welllllllll enough to raise boost. However the most efficient to raise the boost with the less possible heat will creates more horsepower. The important in this very case is not the volumetric efficiency, but adiabatic efficiency.

 

ok... so lets see if my mind follows..

switch to the twin screw (1.2L) and lose some heat... what can we do to make the motor more efficient? Obviously a good head job would be in order.

what other options abound?

I agree that getting the motor more efficient should be priority #1

 

In fact I've made a few more calculation and you guys won't be disappointed. Let's take a LSJ with ALL the following bolt-ons :

1: Intake
2: Race ported head (33% more flow than stock, or 800 CFM)
3 : Header
4 : 3" downpipe without cat
5 : 3" exhaust
6 : Stock M62 blower with a pulley somewhere around 2,8" giving approx. 15 PSI
7 : Valves springs
8 : Redline around 7800 RPM, max HP around 7500 RPM.
9 : Stock Intercooler without any upgrades, no methanol injection.

I've calculated that the motor + the M62 blower can generate 410 BHP, minus 50 BHP robbed by the blower itself, thus giving 360 BHP or ONLY 310 WHP. You know what, it correspond somewhere at the output we can see in the 300 HP LSJ build book.

I can see 350+ WHP with the Lysolm with the same bolt-ons.

So PLEASE stop talking about 400whp on the stock blower ... unless it's juiced !

 

For real nobody is ever going to see 400hp on a stock blower, its not happening, theres too much heat and too much power loss

 

yah thats just assinine to think that lol

 

Believe it or not it's been done. Riceeater on the redline forums did it, but it was very shortly lived as his crank snapped in half! Neutral Balance shafts would have saved his engine at those high rpms he was running.

 

someone already did that. . .and the same thing that allowed him to see 400HP on a stock blower is going to be the same thing that will allow anyone else to see 400HP on a twinscrew. A good port and polish job on the head.

I dont know how many times its been said, the wall for our cars isnt the blower, its the head. Pure and simple. The twinscrew swap isnt going to stop the wall, its just going to push it up by 40HP or so at best. The twinscrew is doing nothing more than using less HP to make the same PSI. Which is a good thing, but for 3,000 dollars its not.

 

fixed

 

Not really. More flow (CFM) is proportional to psi no matter what the compressor. You have to change the volumetric efficiency of the engine (cams, ported head, etc.) to achieve more airflow at a lower pressure ratio.

 

actually what you fixed doesnt make any sense. 17 PSI from a twinscrew and 17 PSI from a roots are bothing pushing the same amount of air. Only difference is with the twinscrew i might take 10-15 less HP to make that 17 PSI as well as drop the temps 20F or so to make the same PSI.

 

ummm ok if cfm is related to PSI then how come the procharger will push more CFM at much much less PSI??? it's all about CFM... and the T/s SHOULD have the capabilities to push more CFM thus making the same HP at less PSI...


it's not about PSI... it's about CFM... and unless the Ts and the HEATON push the same MAX CFM then things will be different... and yes efficiency is a bit part as well because if it's efficient spinnin at x internal rpms and you're spinning it any faster than that you're just going to create more heat and more chance of failure...

the only way that CFM and PSI have a relation is that the more CFM you push on any given application the PSI goes up.. but depending on blower design and efficiency you can push out more CFM with less psi, what would be the point of doing a turbo or procharger or any swap if increasing the amount of max cfm didnt in turn give you the abillity to make more power with less effort ??

 

You contradicted yourself in the bolded part.

Pressure is simply a result of airflow. The more airflow you force into an engine, the higher the pressure will become in the intake manifold. Compressor swaps don't change the engine's ability to ingest more air. Top end modifications do.

The purpose of changing compressors is to utilize higher adiabatic efficiency at a given airflow and pressure ratio.

Edit: Reading your post again, you're confusing a whole lot of different things here, mainly compressor efficiency and engine volumetric efficiency.

Compressor swaps increase power output because the new compressor can push more airflow at higher pressure ratios unlike the eaton and still maintain high adiabatic and thermal efficiency. The eaton can push more airflow than any of our cars could ever handle, however it cannot do it at high pressure ratios needed to force those large amounts of air into a small displacement engine. This can be solved by increasing engine speed (rpm) allowing large amounts of air to be ingested while maintaining low pressure. However to keep the Eaton in its efficiency range, you would have to spin the engine upwards to 19,000 rpm to utilize the airflow the Eaton is capable of.

Now lets introduce a turbo into the equation. At pressure ratios of 2+ the turbo maintains adiabatic effiency while being able to push large amounts of airflow.

The Eaton will rival a lot of turbos when it comes to being able to push air, but what it cannot do is push airflow against high pressure. This is the reason an M90 swap would actually make less power than keeping the stock M62 because the M90, although capable of higher airflow, is less capable of doing it at a high pressure ratio. These blowers are made for higher displacement engines where low pressure ratios and high airflow is possible.

What you were stating earlier was that "blower X" will push more air into the engine than "blower Y" at lower pressure. That simply isn't true. An engine's volumetric efficiency dictates how much air can be ingested at a given pressure. A blower swap will not change that.

 

i didn't contradict myself at all ... re read it... it's about CFM... not PSI... a different blower can push out more HP on less PSI..

the bolded statement says... that regardless of application... as you're going up in the RPMs and the blower is pushing more air.. yes boost will climb... however that doesn't mean you can't have less boost and still have more HP...

CFM is what gives the engine more power.. and while you might be limited flow wise by certain parts of the engine... that does not change that given a free flowing engine that the T/s will be able to push more air...

ok... here the T/s kit was pushing we'll say about 300 WHP on 20PSI (since it was hitting 280 around 5500 RPMS and had some issues.....)
and... the procharger has the ability to push up to 600+ HP on 24PSI.... t

the T/s has the ability to hit 325WHP but after that the blower will more than likely be maxed out... heat wise ... rpm wise.. and money wise... bottom line for me with the T/s is why spend 3K for something that'll give you 50 or so HP..when there are other options that have more opportunities for around the same price..

 

Reread my post above. Because the procharger has the ability to push 600hp+ of airflow at 24psi doesn't mean thats what it will dyno at on a 2 liter engine. At 24psi, its not possible for a 2 liter engine to ingest that much airflow. 24psi measured in the intake manifold from one compressor will be the same amount of airflow than any other compressor at 24psi.

This is where you are confusing engine VE with compressor efficiency.

 

ohhhhhhh, we're getting into VE. this should be fun.

 

Its a good bolt on for a daily driver in the 12's. If the blower is maxed out, then you still have room to upgrade other parts for additional HP. This is on a basically stock car. Add a rebuilt JBP wild crate engine and unlesh the power simple as that.

 

i wouldnt let them rebuild my cat's litter-box.

 

i laughed a bit.

people are looking at me funny now. thank you

 

Well whoever you choose you can still build the engine.

My JBP 3" exhaust is excellent! Don't know about the rest of their stuff...

 

you dont seem to understand. No one is arguing that the twinscrew or the procharger can push out more CFM with less heat and power draw. What you dont understand is that not matter how much air you force at the engine, its still only going to be able to take in so much air at a time.

PSI is a measure of resistence, its the resistence of air to get into the engine. 10 PSI on a 2.0 ecotec is a different CFM of air than 10 PSI on a 2.2L ecotec. PSI is what causes heat in the superchargers. Heat causes a wall, heat causes loss of HP, heat causes blown engines.

But if you have one LSJ with a procharger, and one LSJ with a twinscrew, and one LSJ with an eaton, all 3 engines are reading 10 PSI, all 3 engines will be taking in the exact same amount of air. While someone engines will produce more HP than others, due to the amount of heat produced and the power draw or efficiency of the blower.

PSI is not a measure of HP potential, CFM is, but its main concern is how much CFM the engine can take in. Lets say you have 2 LSJ motors with M62 blowers. One engine is entirely stock, its make 12.5 PSI. Its making 205WHP. The other engine has a stock pulley, full exhaust, heavily modified head, oversized valves, and a free flowing intake. The second engineis only making 10 PSI, because the free flowing engine is able to take in more air per revolution than the stock one due to the flowing head. Now lets say this modified engine is making 240WHP at 10psi. Now why is it making more HP? Its using the same blower, same amount of CFM. But what has changed is the engine. Its now more efficient. Less heat is produced when compressing the air. The air moves more easily through the engine.

This is the same effect the TVS will have. Less heat is being produced along with less power draw. Thats the only thing increasing HP. The CFM is not creating anymore HP at the same PSI of the m62. So when/if the TVS comes out and makes 22 PSI if you have an m62 making 22 PSI, both blowers will be moving the exact same CFM of air. The only difference is the TVS will take 30-40 less HP to move the same amount of air.

Do you now understand why it doesnt matter what type of FI your using. There will still always be the limits of the stock head as a major wall? And that just because one FI type moves more CFM doesnt mean the engine can ingest the extra CFM?

 

HOw much did you pay for that JBP 3" exhaust?

BTW - Ridemlow03 is absolutley right. Why pay 3K for a maxed out blower when you can pay alittle more and get a non maxed out turbo kit?

 

u can go past 7k in our engines with the proper upgrades, aka neutral balance shafts, and high speed valve springs.

 

HAHA I love the excuse, I'd have to agree though lol, and while your at it might as well get some forged pistons and rings ;P

 

yeah already have a few sets