Forced Induction How About A Vortech V3-si Trim On A 94 Cobra?

[Noobz347]

The KB gets much hotter than centrif.

Myth/Legend

Non-intercooled KBs generally have cooler discharge temps than non-intercooled centri's at equal boost levels.

Please post your source for the claim (if you happen to have one handy). I would like to know where that comes from.

The only time a KB runs hotter is when it is by-passed and recirculating discharge back through the super charger. When the bypass valve is closed and air is being forced into the motor (not recirculated) then discharge temps are considerably lower than that of a centri.

The reason is because the twin screw uses such a LARGE surface area to compress the air charge vs. the small housing and blades found within a century. The twin screw also spins at lower speeds (which is one reason why centris tend to make more top end... air velocity).

The article that I recall seeing this in was MM&FF and I'm pretty sure it was in a 2011 issue. I can probably dig it up if you'd like to see it.

 

[revhead347]

Myth/Legend

Non-intercooled KBs generally have cooler discharge temps than non-intercooled centri's at equal boost levels.

Please post your source for the claim (if you happen to have one handy). I would like to know where that comes from.

The only time a KB runs hotter is when it is by-passed and recirculating discharge back through the super charger. When the bypass valve is closed and air is being forced into the motor (not recirculated) then discharge temps are considerably lower than that of a centri.

The reason is because the twin screw uses such a LARGE surface area to compress the air charge vs. the small housing and blades found within a century. The twin screw also spins at lower speeds (which is one reason why centris tend to make more top end... air velocity).

The article that I recall seeing this in was MM&FF and I'm pretty sure it was in a 2011 issue. I can probably dig it up if you'd like to see it.

That's not a myth, legend what ever want to call it, it's a fact. A screw compressor creates more heat a centrifugal compressor. A roots compressor creates even more heat. The only method of compression more efficient that centrifugal compression is axial compression. It has nothing to do with surface area either. The impellar in a centrifugal compressor doesn't compress air, it accelerates it. The high speed air is compressed by the diffuser.

Kurt

 

[Noobz347]

That's not a myth, legend what ever want to call it, it's a fact. A screw compressor creates more heat a centrifugal compressor. A roots compressor creates even more heat. The only method of compression more efficient that centrifugal compression is axial compression. It has nothing to do with surface area either. The impellar in a centrifugal compressor doesn't compress air, it accelerates it. The high speed air is compressed by the diffuser.

Kurt

Source?

Here's mine:

Modified Mustangs Magazine

"The 17 Myths of Supercharging"
'07-'08

December
1. Supercharged engines use more fuel.
2. Supercharged engines must use high octane fuel.
3. Superchargers need an ignition system upgrade.
4. Superchargers must run retarded ignition timing

January
5. Superchargers make the engines run hotter.
6. Superchargers cause engine knock.
7. Superchargers are noisy.
8. Bolt-Ons can make more HP for less money.

Febuary
9. You must run forged pistons and rods with a supercharger.
10. Superchargers need maintainance and rebuilding.
11. Raising compression makes the same HP as supercharging.
12. Both turbos and superchargers have instant no lag boost.
13. Superchargers blow out head gaskets.

March
14.Superchargers are less efficient than turbochargers.
15. Supercharging adds excessive weight.
16. Superchargers "heat soak".
17. Higher compression ratios cost less than supercharging.

Oh... and I can tell you first hand that my V1 S-Trim, non-intercooled, could not even BEGIN to approach the boost levels of a KB without a cooler. Although, it did make more peak HP with less boost.

 

[99FiveOh]

Tell that to all the guys who popped their head gaskets because of the heat made by KB's. Perhaps KB's do run a little cooler than centri's at boost, but you have to remember that the KB is boosting much more often since it reaches full boost much sooner. Therefore more heat and a huge chunk of HOT METAL sitting on top of your motor ever soaking up more heat.

Since a Vortech builds boost up higher in the RPM band it's not exposed to the heat as much. So when you do decide to get on it the housing is much cooler, not to mention it's mounted off to the side instead of RIGHT ON TOP of a super hot motor. At full boost I could imagine the Vortech making more heat due to it's design but that's about it.

Oh, and whoever wrote that list of so called "myths" is full of bologna! I could pick apart almost all of those and I'm sure there are more than enough members of this site that can chime in who have probably experienced a few of those first hand.

Superchargers don't need maintainance and rebuilding? Get real. It's a mechanical device and WILL require service at some point in it's life. That magazine obviously had their supercharger kit advertisers' interests in mind when they made that list, plain and simple.

 

[Noobz347]

Tell that to all the guys who popped their head gaskets because of the heat made by KB's. Perhaps KB's do run a little cooler than centri's at boost, but you have to remember that the KB is boosting much more often since it reaches full boost much sooner. Therefore more heat and a huge chunk of HOT METAL sitting on top of your motor ever soaking up more heat.

Since a Vortech builds boost up higher in the RPM band it's not exposed to the heat as much. So when you do decide to get on it the housing is much cooler, not to mention it's mounted off to the side instead of RIGHT ON TOP of a super hot motor. At full boost I could imagine the Vortech making more heat due to it's design but that's about it.

Oh, and whoever wrote that list of so called "myths" is full of bologna! I could pick apart almost all of those and I'm sure there are more than enough members of this site that can chime in who have probably experienced a few of those first hand.

Superchargers don't need maintainance and rebuilding? Get real. It's a mechanical device and WILL require service at some point in it's life. That magazine obviously had their supercharger kit advertisers' interests in mind when they made that list, plain and simple.

Wow... defensive much?

The magazine article wrote the list of myths. You should read the articles before jumping to conclusions.

At any rate (attempting to resume discussion here)....

Granted, I'm not sure comparing a 2.2L Kenne Bell and a V1 S-Trim is an apples to apples comparison, but those are the two superchargers that I own. At 10 psi, my Vortech was showing discharge temps of a little over 170*. The KB on the other hand, gets to a hair over 160* @ 13/14 psi. Both are at or near an ambient air temp of 70*.

Therefore more heat and a huge chunk of HOT METAL sitting on top of your motor ever soaking up more heat.

It's interesting that you mention that because one of the points that I see mentioned over and over again is about how the engine soaks the supercharger and not the other way around. It's actually mentioned in the article that you're so upset about.

 

[99FiveOh]

Ahh hell, let's pick them apart shall we?

December
1. Supercharged engines use more fuel. ***BS, you are creating parasitic drag on the engine which is causing the engine to work harder, which also caused it to burn a little more fuel
2. Supercharged engines must use high octane fuel. ***They don't have to use higher octane, but if you want to realize the power potential of that expensive investment it's highly recommended. A tune could easily be written to use 87 octane though at the expense of A BUNCH OF POWER!

3. Superchargers need an ignition system upgrade. ***You make 15+ lbs of boost you're gonna start blowing your spark out. I have the dyno graph to prove that at 15 psi my own plugs gapped to .28 were being blown out.
4. Superchargers must run retarded ignition timing ***LOL! Seriously? Do you really want to be running 20* total timing with 200+ degree inlet temps under boost? Didn't think so!!, your head gaskets and pistons wouldn't appreciate it.

January
5. Superchargers make the engines run hotter. *** This is probably really a myth. My engine doesn't make any more heat under boost.
6. Superchargers cause engine knock. *** Well, yes and no. If you boost the crap out of your engine all the time and it's not built for it (ie: stock) I'm sure it'll being knocking before it comes apart! But no, this is for the most part a myth.
7. Superchargers are noisy. *** WTF are these guys smoking? I really want to know so I can get me some of that !! My V1 was loud enough to wake the dead and this V2 that supposed to be quieter, is almost just as loud! But I LOVE IT!! (the people at fast food drive throughs don't like it though)

8. Bolt-Ons can make more HP for less money. *** True I suppose. Dollar for Dollar I'm sure a SC will beat out NA combos to a point. There is a point though were a motor has to be built to realize more HP.

Febuary
9. You must run forged pistons and rods with a supercharger. *** this was actually true back in the old days. Now cars can be tuned to PULL TIMING (myth addressed above) and keep your hypercraptic pistons blissfully turning your crank for years to come.

10. Superchargers need maintainance and rebuilding. *** Of course they do. All mechanical devices need this at some point. Myth confirmed!
11. Raising compression makes the same HP as supercharging. *** This isn't a myth, it's pure ignorance if you think this is true.
12. Both turbos and superchargers have instant no lag boost. *** Actually with the advent of ball bearing turbos they can be sized to make almost instant boost right there with roots and twin screw blowers! So myth confirmed.
13. Superchargers blow out head gaskets. *** YES THEY WILL if your tune isn't right on or if you run low octane fuel (myth addressed above). Point blank, ping under boost and watch your head gaskets pop like popcorn. Oh you have studs and an expensive set of O ringed gaskets? Great, now your motor will spit a rod out of the side of the block, that is unless you kept the fuse in the motor, the hypercraptic pistons!

March
14.Superchargers are less efficient than turbochargers. *** Turbos are more efficient. They are practically free HP. You do have a small amount of parasitic drag on the motor, but nothing compared to a blower of any kind.
15. Supercharging adds excessive weight. *** Define excessive!!
16. Superchargers "heat soak". *** KB's heat soak badly because they are sitting at the top of a fire making machine. And with a hood blanket insulating all that heat, they get even hotter!
17. Higher compression ratios cost less than supercharging. *** They do. I could have bought a brand new set of 58cc heads and new forged pistons for the price I paid for my USED blower. Of course if you're comparing it to say a powerdyne then this may be considered a myth. Too many variables to call it one way or the other.

Anyway, this was fun. I confirmed almost all of these myths. You can't trust what a freakin' magazine tells you. Their only concern is selling more products for their advertisers. I've actually had dyno shops tell me they deliberately altered the numbers of a given product to show more HP/TQ in order to make the magazine happy and sell products.

 

[99FiveOh]

Wow... defensive much?

The magazine article wrote the list of myths. You should read the articles before jumping to conclusions.

At any rate (attempting to resume discussion here)....

Granted, I'm not sure comparing a 2.2L Kenne Bell and a V1 S-Trim is an apples to apples comparison, but those are the two superchargers that I own. At 10 psi, my Vortech was showing discharge temps of a little over 170*. The KB on the other hand, gets to a hair over 160* @ 13/14 psi. Both are at or near an ambient air temp of 70*.



It's interesting that you mention that because one of the points that I see mentioned over and over again is about how the engine soaks the supercharger and not the other way around. It's actually mentioned in the article that you're so upset about.

I do tend to get a little defensive when I'm called out for "misinformation". I've ready countless threads, especially when I was searching for which supercharger to get, where people with KB's were popping their head gaskets.

 

[Noobz347]

14.Superchargers are less efficient than turbochargers. *** Turbos are more efficient. They are practically free HP. You do have a small amount of parasitic drag on the motor, but nothing compared to a blower of any kind.

I won't be drawn into your rant however...

I always love the FREE HORSEPOWER myth. Nobody ever considers the parasitic drag of such a large exhaust restriction.

Actually, the last I checked, the parasitic draw differences between a turbo and a blower making equal boost was about 5% in favor of the turbo. The turbo was still the better but it's not free.

 

[Noobz347]

I do tend to get a little defensive when I'm called out for "misinformation". I've ready countless threads, especially when I was searching for which supercharger to get, where people with KB's were popping their head gaskets.

I did the same when I made the decision to switch. It was over a period of a number years. It's often difficult to separate the internet, 'fan boy' data from real data. All too often I see the same half truth regurgitated from forum to forum.

 

[revhead347]

I love the one about excessive weight. If you are worried about a few lbs of extea weight, then maybe wouldn't have bought a Mustang in the first place. You have to understand that the people who sit down and write those articles are journalists, not specializing in any of the mechanics of an engine. I got my degree in aeronautics and I'm working on my master's in the field. Compressors are a huge part of that. I saw something quite contradictory there. A turbocharger is more efficient than a supercharger, which is true, but you never see an exhaust turbine bolted to a screw compressor to make a turbocharger. I suppose the addition of a transmission might have something to do with that, but it would be worthwhile if it was more efficient.

Kurt

 

[Noobz347]

Oh... and I can tell you that after having run the KB for the last 6 or so years, that I've NEVER popped a head gasket.... never. Blowing head gaskets is a product of poor tuning, not the kind of power adder that you use.

 

[Noobz347]

I love the one about excessive weight. If you are worried about a few lbs of extea weight, then maybe wouldn't have bought a Mustang in the first place. You have to understand that the people who sit down and write those articles are journalists, not specializing in any of the mechanics of an engine. I got my degree in aeronautics and I'm working on my master's in the field. Compressors are a huge part of that. I saw something quite contradictory there. A turbocharger is more efficient than a supercharger, which is true, but you never see an exhaust turbine bolted to a screw compressor to make a turbocharger. I suppose the addition of a transmission might have something to do with that, but it would be worthwhile if it was more efficient.

Kurt

True, but that wouldn't make a whole lot of sense since there's already an 8 stage compressor before the combustion section.

 

[revhead347]

Couple other myths there. Adding a forced induction system generally improves fuel efficiency. The parasitic drag pays for itself. Adding compression is not the same as adding boost. I think those articles were written by a blower hater. He probably drives an old big block ford with a huge cam that is impossible to drive on the street on a hot day and in traffic. He is tired of getting beaten by Srt-4s and turbo Civics so he is trying to convince more people to make the same mistakes he did so that others can be as miserable.

Kurt

 

[99FiveOh]

I won't be drawn into your rant however...

I always love the FREE HORSEPOWER myth. Nobody ever considers the parasitic drag of such a large exhaust restriction.

Actually, the last I checked, the parasitic draw differences between a turbo and a blower making equal boost was about 5% in favor of the turbo. The turbo was still the better but it's not free.

And flowmasters don't present any drag on the motor? You can't tell me a turbo with an open down pipe is creating more of a restriction than a full exhaust system with a chambered muffler. Turbos are as free as it gets. And they don't destroy your front main bearing either, or is that myth too?

 

[Noobz347]

And flowmasters don't present any drag on the motor? You can't tell me a turbo with an open down pipe is creating more of a restriction than a full exhaust system with a chambered muffler. Turbos are as free as it gets. And they don't destroy your front main bearing either, or is that myth too?

What I'm telling you is that the difference is parasitic loss is about 5%.

 

[99FiveOh]

Is that 5% at idle? Low boost? Maximum boost? I know roots and centri's take considerable power to drive at maximum speed.

 

[Noobz347]

Is that 5% at idle? Low boost? Maximum boost? I know roots and centri's take considerable power to drive at maximum speed.

That's an average across the power band for housings of similar size and boost potential. IIRC, that figure came from a talking paper about the adiabatic efficiency.

 

[InMyPrimeSVT]

Holy thread hijack!!! Knock it off! It's about this guys install!

 

[99FiveOh]

Holy thread hijack!!! Knock it off! It's about this guys install!

Actually it's an opinion needed and information thread. I'm sure he'll be giving us that "****" you were talking about earlier in another fresh thread, in which case we'll keep our arguments to ourselves. But this is good info and will help many in the years to come!

 

[99FiveOh]

Myth/Legend

Non-intercooled KBs generally have cooler discharge temps than non-intercooled centri's at equal boost levels.

Please post your source for the claim (if you happen to have one handy). I would like to know where that comes from.

The only time a KB runs hotter is when it is by-passed and recirculating discharge back through the super charger. When the bypass valve is closed and air is being forced into the motor (not recirculated) then discharge temps are considerably lower than that of a centri.

The reason is because the twin screw uses such a LARGE surface area to compress the air charge vs. the small housing and blades found within a century. The twin screw also spins at lower speeds (which is one reason why centris tend to make more top end... air velocity).

The article that I recall seeing this in was MM&FF and I'm pretty sure it was in a 2011 issue. I can probably dig it up if you'd like to see it.

Here is my source, Don Lasota: http://www.lasotaracing.com/techKB.html

He goes on to say on this page that KB's see 230* and above ACT temps when using more than 10#'s of boost. My S trim at 15.5 psi was putting out a hair over 200* and this was after 5 consecutive pulls on the dyno.

I'm just trying to make the OP feel like he made a worth while purchase and don't want him to be thinking that maybe he should have gone with a KB. KB's are awesome superchargers when you can intercool them. There's a guy on Corral that made a sweet looking A2A setup for his KB and his dyno sheet is sick! Dude's making like 600 ft lbs of torque by 2500 rpm! I'll bet that's one of the craziest rides you could take in a street car. If this guy could make a manifold setup like he has there for a 94/95 and sell me one I'd probably switch to a KB myself.

But comparing the 2 different blowers non-incooled the Vortech simply runs cooler.

edit: here's his dyno sheet: