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Author Topic:   Supercharger Question
SteveLaRiviere
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Posts: 45869
From: Saco, Maine
Registered: May 99

posted 03-29-2002 01:13 PM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
A friend of mine asked me an interesting question and I thought I ask it here:

On a centrifical supercharger that claims a 30% gain in horsepower, would that apply across the board? {i.e. a 300 hp to 390 hp, 400 hp to 520 hp, etc}

I say no, because the supercharger overcomes flow inefficienties with lower powered engines, so the gain is lessened with more efficient engines. What do you guys think? Has anybody seen dyno comparisons at different level base horsepower engines?

------------------

'70 Mustang Mach 1 M code 351C 4V/FMX/3.25 open
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Lok
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip

MCA Member # 47773

[This message has been edited by SteveLaRiviere (edited 03-29-2002).]

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Moneymaker
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From: Lyons, IL, USA
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posted 03-29-2002 01:32 PM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
15% TOPS! We have been there and done that! Shelby and Paxton used to claim a 46% increase on the 66 GT-350S cars. That would equate to 446 HP on the 306 HP Shelby 289. I DON'T THINK SO! That's only about 50 HP less than MM makes!
The Shelbys only went about .70 quicker with the blowers according to the road test reports of the period.

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Alex Denysenko
Co-Administrator and Moderator/ non 65-66 Mustang owner sensitivity co-ordinator

NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Part time secret agent license #0089
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SteveLaRiviere
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Posts: 45869
From: Saco, Maine
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posted 03-29-2002 01:41 PM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
But do you think the increases vary with different base horsepowers on the same engines?

------------------

'70 Mustang Mach 1 M code 351C 4V/FMX/3.25 open
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Lok
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip

MCA Member # 47773

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Moneymaker
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From: Lyons, IL, USA
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posted 03-29-2002 02:05 PM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
The lower the initial output, the greater the gain from a supercharger. I can see a 75 to 80 HP increase on a stock LT-1 or 5.0 and a 1000 HP increase on a 5000 HP top fuel motor. But, on a good say 400 to 450 HP S&S engine, the addition of a centrifical blower might only see a 30-50 HP gain. It is already pretty efficiant and drawing air in.

------------------
Alex Denysenko
Co-Administrator and Moderator/ non 65-66 Mustang owner sensitivity co-ordinator

NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Part time secret agent license #0089
US Class Nationals link

[This message has been edited by Moneymaker (edited 03-29-2002).]

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SteveLaRiviere
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From: Saco, Maine
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posted 03-29-2002 02:08 PM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
That's what I thought. My friend's car is almost put together, and we're looking forward to seeing what kind of a difference the Paxton makes.

------------------

'70 Mustang Mach 1 M code 351C 4V/FMX/3.25 open
'72 Mustang Sprint Coupe 351C 4V/FMX/4.30 Trac Lok
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip

MCA Member # 47773

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67Coupster
Gearhead

Posts: 189
From: Fortson, GA, USA
Registered: Oct 2001

posted 03-29-2002 03:16 PM     Click Here to See the Profile for 67Coupster   Click Here to Email 67Coupster     Edit/Delete Message   Reply w/Quote
I went from 14 flat at around 97 mph on my modified '95 Lightning to 12.20's at about 113 mph with the installation of a Vortech S-trim in the same conditions. It was just not installed as Vortech intended. I installed the 8-rib pulley setup to reduce belt slippage along with 30lb injectors and had Chris Johnson of Johnson Motorsports tune it with a wide-band O2 sensor on some back roads near his house in Mobile. This was using the software that Mike Wesley came up with. I think that was a little more than 15%

Here is a link to some of Chris Johnson' comments on the truck:

http://www.jmschip.com/oldnews.html

He is probably one of the best chip burners in the business.

------------------
James
67 Coupe
393W, AFR 185, 4 Speed, 4.11 9 inch
7.09 @ 97MPH 1/8
1.55 60'

[This message has been edited by 67Coupster (edited 03-29-2002).]

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Moneymaker
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Posts: 27499
From: Lyons, IL, USA
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posted 03-29-2002 05:37 PM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
You all know that you can optimize anything!

Let's see now, the article says a previous best of 13.18 and you say 14.00. Which one is it? That's about a second disparity there.
I love blowers and used to race them. I still do many installations, but I am a realist and fact is fact. No blower on it's own will give you a 30 to 50% increase in horse power.

------------------
Alex Denysenko
Co-Administrator and Moderator/ non 65-66 Mustang owner sensitivity co-ordinator

NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Part time secret agent license #0089
US Class Nationals link

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mvierow
Gearhead

Posts: 209
From: Bay Area, Ca
Registered: Apr 2001

posted 03-29-2002 06:14 PM     Click Here to See the Profile for mvierow   Click Here to Email mvierow     Edit/Delete Message   Reply w/Quote
It makes sense that a stock engine would see greater gains than a modified one when the same blower was added to each one, but the modified engine would also be able to handle higher boost than the stock motor. So all in all, the blower is capable of delivering 30% increases, or more for that matter, but not without tuning it to your application. Of course this is all specific to the blower, the maximum boost capable, and the motor its going on.

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Daniel Jones
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Posts: 898
From: St. Louis, MO
Registered: Aug 99

posted 03-29-2002 07:17 PM     Click Here to See the Profile for Daniel Jones   Click Here to Email Daniel Jones     Edit/Delete Message   Reply w/Quote
>On a centrifical supercharger that claims a 30% gain in horsepower, would
>that apply across the board? {i.e. a 300 hp to 390 hp, 400 hp to 520 hp, etc}

Not if you're keeping the drive speed constant. However, to a first
approximation, you might expect the total horsepower increase to be the
same (300 to 390 HP, 400 to 490, 500 to 590, etc.).

The gain a supercharger provides is dependent upon its flow rate, as limited
by the compression ratio of the engine. A supercharger is basically a pump,
with a given flow rate versus impellor RPM curve. If one engine inhales
twice the flow of another (for instance, a 250 HP 5.0 versus a 500 HP 460),
it will require twice the flow out of the supercharger to provide the same
boost (all other things equal, to a first approximation). This disparity
in supercharger flow rate versus engine boost level is why boost is not a
good measure of a supercharger. A lower boost level can mean either the
engine is efficiently passing it's flow through the engine or it can mean
it's uselessly blowing the boost out the tailpipe (due to excessive cam
overlap). A higher boost level can either mean the supercharger is producing
a lot of flow or the engine is restricting the superchargers output. Boost
can be useful but you must know the context.

There are various types of superchargers, some are positive displacement
(Roots and Lysholm intermeshing screw) and some are not (axial and
centrifugal flow). Both types of blowers produce flow as a function of
impellor speed. The primary difference is how the boost varies with RPM.
A positive displacement supercharger sweeps out a fixed amount of flow
with each revolution of the impellor so flow varies linearly with impellor
RPM. Double the speed and you get double the flow. Axial (Latham) and
centrifugal (turbos, Vortech, Paxton, etc.) superchargers produce flow
that is proportional to the square of the impellor speed. Double the
sped and you'll quadrouple the flow. That may seem like a good thing
(more flow = more boost) but it's not. The nonlinear flow curve limits
the working range of a centrifugal supercharger. Pulley one to produce
meaningful boost at 2000 RPM and you'll over-boost the engine at 6000 RPM.
The linear output of positive displacement blowers allows them to operate
over a wider RPM range without overboosting. Turbos get around this by
installing wastegates which bleed off boost above a certain level.

A direct by-product of supercharging is an increase in the (dynamic)
compression ratio, with an attendant increase in temperature (pressure
times volume is proportional to temperature for an "ideal" gas... PV=nRT).
This is why it's a good idea to reduce the static compression ratio when
adding a supercharger.

Dan Jones

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67Coupster
Gearhead

Posts: 189
From: Fortson, GA, USA
Registered: Oct 2001

posted 03-29-2002 07:19 PM     Click Here to See the Profile for 67Coupster   Click Here to Email 67Coupster     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Moneymaker:
Let's see now, the article says a previous best of 13.18 and you say 14.00. Which one is it? That's about a second disparity there.


That was with the blower installed as delivered from Vortech 6-rib pulley, stock 19lb injectors. Dropped from 14 flat to 13.18. Took it down to him installed the injecters and then tuned it in with the proper A/F ratio and it dropped ET to the 12.20's in 90 degree heat. Ran 3 11.90 passed later that fall in some 50 degree temps. It was pig rich(safe) the way Vortech has them tuned. There's no way a early Lightning with the limited mods I had and still speed density would run low 13's. Don't worry your not the first person to doubt how well that truck ran for the limited amount of mods I had on it. It had them where it counted. Heavly ported exhaust ports, cleaned up intake and lower intake ports also a full off-road Bassini exhaust and 12 psi of boost will do wonders. At the track with race gas and the boost timing retard turned off it picked up about 50hp over the street tune.

All I was trying to say was I went from somewhere over 300hp to over 500hp just from the addition of a supercharger which is a little more than 15%. 95 mph naturally aspirated to 112 to 114 mph supercharged at 4200lbs, plently of on line calculators to figure the HP. Anyway no big deal I joined this site to learn how to make a early model Fords with leaf springs haul butt and I came to the right place.
------------------
James
67 Coupe
393W, AFR 185, 4 Speed, 4.11 9 inch
7.09 @ 97MPH 1/8
1.55 60'

[This message has been edited by 67Coupster (edited 03-29-2002).]

[This message has been edited by 67Coupster (edited 03-29-2002).]

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kid vishus
Gearhead

Posts: 6590
From: middle of NC
Registered: Oct 2000

posted 03-29-2002 07:34 PM     Click Here to See the Profile for kid vishus   Click Here to Email kid vishus     Edit/Delete Message   Reply w/Quote
Wow Dan

The knowledge you possess is amazing.

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Moneymaker
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From: Lyons, IL, USA
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posted 03-29-2002 08:37 PM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
Dan, I could not have said it better myself!
James,I congratulate you on the outstanding performance of your highly modified Lightning. It really runs well and I love those early models.
But...... do you know what I think of on line HP calculators?
I have the exact same regard for them as I do magazine mechanics!
ZERO!
Every on line calculator I have ever tried is approximatly 4 to 5% high.
Makes for great bench and forum racing though!

------------------
Alex Denysenko
Co-Administrator and Moderator/ non 65-66 Mustang owner sensitivity co-ordinator

NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Part time secret agent license #0089
US Class Nationals link

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RPM289
Gearhead

Posts: 155
From: Phenix City, AL
Registered: Feb 2002

posted 03-31-2002 10:43 PM     Click Here to See the Profile for RPM289   Click Here to Email RPM289     Edit/Delete Message   Reply w/Quote
I will say that James's Lightning was one of the fastest speed density trucks in the Lightning world . The are still talking about it on the Lightning site. I don't know how accurate the calculators are but I will say I have "seat of pants dyno" experence in the passenger seat of the truck before the super charger and after it was installed MAJOR change! His truck is a great example of what can be done with a few well picked mods and a great setup. At any rate a 4200# truck running 11.90's is definatly a accomplishment. Wish ya haden't sold the L James you could pull the Stang with it!

------------------
66' Mustang
95' Lightning
84' 351w Ranger

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Moneymaker
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From: Lyons, IL, USA
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posted 03-31-2002 11:16 PM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
Speaking of supercharged Lightnings...... I might mention that I have a very close friend with a well known Lightning that I spent a lot of time with a few years ago. I was involved with the development of this truck and watched it's performance increase month in and month out. It has the distinction of being the FIRST stock bodied Lightning in the nine second zone.
His name is Jim Gilbert from Ohio and if you know anything about Lightning racing you know of Jim.
I think I know just a little about what you can do with a blower on a Lightning or anything else for that matter. Given the right managment system, boost pressure, and valve timing, the performance increase can be phenominal. All you have to do is manage to keep the head gaskets and pistons in it.
I have the same passion for blowers that No2Mike has for nitrous oxide. They both provide instant never ending horsepower. However, the price that you pay for it all depends on how much abuse your engine and wallet can withstand.
There are only three dynos that I believe in.
1) A Superflow
2) The four wheel kind
3) A power/speed slide rule
I'll race ANY on line dyno at any track anytime!
Peace

------------------
Alex Denysenko
Co-Administrator and Moderator/ non 65-66 Mustang owner sensitivity co-ordinator

NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Part time secret agent license #0089
US Class Nationals link

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67Coupster
Gearhead

Posts: 189
From: Fortson, GA, USA
Registered: Oct 2001

posted 04-01-2002 05:14 AM     Click Here to See the Profile for 67Coupster   Click Here to Email 67Coupster     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Moneymaker:
His name is Jim Gilbert from Ohio and if you know anything about Lightning racing you know of Jim.
All you have to do is manage to keep the head gaskets and pistons in it.


Jim's truck is awesome. I had the pleasure of seeing it run at a couple of the FFW's when I was running in the stock Lightning class.(When it was still heads up racing) Your dead on about the head gaskets I blew one right before I sold the truck. Talk to ya later!!


------------------
James
67 Coupe
393W, AFR 185, 4 Speed, 4.11 9 inch
7.09 @ 97MPH 1/8
1.55 60'

[This message has been edited by 67Coupster (edited 04-01-2002).]

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MrWesson22
Gearhead

Posts: 1286
From: Dacula, GA
Registered: Sep 2000

posted 04-01-2002 12:32 PM     Click Here to See the Profile for MrWesson22   Click Here to Email MrWesson22     Edit/Delete Message   Reply w/Quote
So if you had an all forged, race-prepped short block with only 8:1 static CR and put a blower on pushing upwards of 15psi, you'd only gain about 15% over what this motor pulled n/a?? I find that a little difficult to swallow. Maybe I'm reading it wrong.

------------------
Neal
Member #723
[email protected] AIM: MrWesson22

69 Gulfstream Aqua Grande
351C/Toploader 4sp

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Daniel Jones
Gearhead

Posts: 898
From: St. Louis, MO
Registered: Aug 99

posted 04-01-2002 01:05 PM     Click Here to See the Profile for Daniel Jones   Click Here to Email Daniel Jones     Edit/Delete Message   Reply w/Quote
>The knowledge you possess is amazing.
>Dan, I could not have said it better myself!

Thanks guys! Pretty basic stuff when it comes to supercharging. I had a leg
up on understanding supercharger theory from my jet engine and turbomachinery
classes. Jet engines and superchargers have a lot in common. The axial flow
Latham supercharger is basically just the compressor stage of an axial flow
jet engine. Likewise, a centrifugal supercharger is much like a centrifugal
jet engine.

>I will say that James's Lightning was one of the fastest speed density trucks
>in the Lightning world.

I didn't realize it was speed density. What was done for tuning and the
fuel system? I recently purchased a Novi 1000 kit and intend to install
it on my daily-driver '87 Mustang GT which still has speed density.

>Speaking of supercharged Lightnings......

Have you guys heard any reports on the 5.4L supercharged Lightnings? A friend
has one (recently dyno'd at 365 RWHP on a dynojet). He mentioned that there
were something like 48 engine failures on the Lightning email list he's on.
To be fair, these are guys who are turning up the boost but with the very long
stroke of the 5.4L, it looks like connecting rods are a weak link.

Dan Jones

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67Coupster
Gearhead

Posts: 189
From: Fortson, GA, USA
Registered: Oct 2001

posted 04-01-2002 07:34 PM     Click Here to See the Profile for 67Coupster   Click Here to Email 67Coupster     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Daniel Jones:
>
I didn't realize it was speed density. What was done for tuning and the
fuel system? I recently purchased a Novi 1000 kit and intend to install
it on my daily-driver '87 Mustang GT which still has speed density.

Dan Jones


Fuel system was the Vortech T-rex inline fuel pump along with 30lb injectors. Needed at least 36lb injectors on my combination as it was leaning out above 5000 rpm due to the injectors going static. I'm sure that's why I popped that head gasket right before I sold it. As I'm sure you know the speed density system has a few limitations. Works pretty good at WOT but I had a few driviblity issues that I never did get worked out. All the tuning was done by Chris Johnson(Chris Johnson Motorsports) down in Mobile, AL using Mike Wesleys chipmaster software. I would highly recommend going to mass air and have it tuned with a wide band O2 sensor. The kits come way rich and you can pick up a ton of power while still being safe with the proper tune. Later!!

------------------
James
67 Coupe
393W, AFR 185, 4 Speed, 4.11 9 inch
7.09 @ 97MPH 1/8
1.55 60'

[This message has been edited by 67Coupster (edited 04-02-2002).]

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