How much HP per # of boost

I am just curious how much 5-6 pounds would get me.

I would say about 12-15 for every pound :)

Well.. depends... i think that 10 is for a smaller engine.. 15is more likely for ours.. and 20-25 if intercooled...

You are referring to the rear wheels right? Doesn't seem right to get only 90 HP at the flywheel with 6#s.

Originally posted by Wild1
You are referring to the rear wheels right? Doesn't seem right to get only 90 HP at the flywheel with 6#s.

Without any special tuning that's usually about right for non-intercooled. Having it dialed in to the Nth degree would net you about the same at the wheels. Intercooling will not make such a profound difference as one poster stated, but you could tack on an additional 10 - 15% as a rough guideline and not be too far off.

Originally posted by canbaufo
Without any special tuning that's usually about right for non-intercooled. Having it dialed in to the Nth degree would net you about the same at the wheels. Intercooling will not make such a profound difference as one poster stated, but you could tack on an additional 10 - 15% as a rough guideline and not be too far off.

I beg to disagree.. I gained almost 55 rwhp with just the vortech aftercooler and loosing 1.5psi ... So.. you tell me...

So that is flywheel horsepower... 90 at the flywheel will net less 15% at the wheels... about 75 +/- ... doesn't seem like much for $3000. For a stock motor....

Originally posted by Wild1
So that is flywheel horsepower... 90 at the flywheel will net less 15% at the wheels... about 75 +/- ... doesn't seem like much for $3000. For a stock motor....

For $3150, I picked up over 100hp & 100TQ to the rear wheels. Stock motor.

Now that's what I wanted to hear... 100 RWHP & TQ. Is that with an 8# pulley?

Yes it is, and I'm only seeing 6-7lbs on the gauge. :eek:
Oh yea, and I'm gonna rebuild shortly(head gasket), after 2000 miles! WooHooo! :(

I picked up 150rwhp with my ATI tuner 8# with dual intercoolers, safely tuned to 91 octane gas maxing out at 17 degrees WOT timing. Even with 6# of boost, the ATI did almost 110rwhp over stock -before- we ever even tried to tune it.

That's one bit of data that might help you...

Mike M

Not fair... ls1 heads are far better stock than LT1...

So with 8#s you're already going into the rebuild phase. Yikes! I plan on rebuilding but one bite at a time. First, add the supercharger then save for a rebuild. Perhaps I should start off with 6#s to be "safe"?

ATI - P1SC 6#
High Flow Twin Intercoolers

That would let me grow when I build the bottom end later.

With this non-intercooled 6# I have now the cars runs GREAT... It pulls like no other. The way I'm doing it is blower, then ignition and fuel (walbro 340 going in Saturday), then top end heads/cam (coming very soon), and then rebuild bottom end 355 and leave it 6# until I upgrade to a 12-bolt and intercool it. I expect that will the heads/cam I won't make that full 6# that Im making now, which is actually what I want to happen. I want to eventually go with a custom front mount spearco then run my 11# pulley. Intercooling will make a more noticeable difference on higher boost apps....

So basically, keep the boost low on the stock engine and most importantly DO NOT DRIVE IT HARD ON THE STREET!!!!!! There is no reason to be in boost daily driving... I can easily pull on any honda some other BS without hitting any boost. You keep it cool and only push it when you need to and it will last you how long you need it to.

So is it safe to say on my LT4 head and LT4 hotcam car, I can reach 100 hp with 5-6 pounds of boost? I am dumping the nitrous, but I don't want to run more than 6 pounds of boost, but I don't want my car to be slower than when I used my 100 shot either.

96 WS6 is correct - if you don't beat it unnecessarily, the lifetime of everything concerned will be dramatically extended. Save the Boost for those "showing off" rides you give co-workers, and those handful of Stangs and C5's that insist on racing you even when they know you are going to hand them their ass!

Mike M

Now with the rebuild coming, I spoke with my guy who does the installs on these superchargers. He says he wants to set up the motor, then run 20lbs of boost on race gas and detune it for 15lbs on the pump. OMG, I'm in trouble. :eek:

Originally posted by BAD 97 WS-6
So is it safe to say on my LT4 head and LT4 hotcam car, I can reach 100 hp with 5-6 pounds of boost? I am dumping the nitrous, but I don't want to run more than 6 pounds of boost, but I don't want my car to be slower than when I used my 100 shot either.

Unfortunately, 100hp gain from a centrifugal SC will not produce as dramatic a reduction in ET as a 100hp nitrous shot. Look at the torque curves of the two combos and you will see why. The "area under the curve" is much greater with the nitrous shot. Centrifugal boost is very rpm dependent. OTOH, the nitrous gives the same hp gain at low rpm as at high. A small nitrous shot and a centrifugal is a dynamite combo, if you have the deep pockets needed to make it work :(

Rich Krause

Originally posted by rskrause
Unfortunately, 100hp gain from a centrifugal SC will not produce as dramatic a reduction in ET as a 100hp nitrous shot. Look at the torque curves of the two combos and you will see why. The "area under the curve" is much greater with the nitrous shot. Centrifugal boost is very rpm dependent. OTOH, the nitrous gives the same hp gain at low rpm as at high. A small nitrous shot and a centrifugal is a dynamite combo, if you have the deep pockets needed to make it work :(

Rich Krause

I see what you are saying...Will I get more power for freeway races with a blower though? It seems Boost is better for high speed runs....My nitrous dies off the longer I am spraying...thats what I hate.

Originally posted by The Highlander
I beg to disagree.. I gained almost 55 rwhp with just the vortech aftercooler and loosing 1.5psi ... So.. you tell me...

OK, well ....that sounds very atypical to me. The first thing that comes to mind is that you had a significant amount of knock retard before you put the intercooler on. Did you scan for knock any before you put the intercooler on? I would be willing to bet that is what happened because there's almost no way intercooling alone would give that kind of power increase in and of itself. Especially when you're not even pulleying up to bring the boost level back up to what it was before installation.

The numbers I gave for power gains to expect are based on using the FMU provided in most kits and no special tuning, on an LT1 engine. I feel it is realistic to expect 90 flywheel from 6 PSI non-intercooled given the fact that most kits use an FMU that makes you run very rich and it is necessary to retard timing as well. Once you are dialed in then you can expect 90 RWHP or more......maybe 100+ RWHP if it's really dialed in right (@ 6 PSI). That is my opinion from observing countless examples .....not the "exceptions".

Also, correct me if I'm wrong but I believe for every 10 degree drop in IAT you generally get a 1% power gain. So the gains from an intercooler are not what they are cracked up to be, especially at the lower boost levels. Now, at the higher boost levels where the IAT's are really inflated and intercooling can allow significant amounts of timing to be added .... then intercooling makes a huge difference. FWIW this is what I have learned. It is best to go into this with the attitude that you shouldn't expect much from 6 PSI alone.....because generally it will only feel like a mild punch in top end performance. Like rskrause said, a similar-HP shot of N20 will pack a much bigger low/mid range punch.....in fact, when you have a "100-shot" of N2O it is generally worth nearly 200 extra lbs of torque :eek: (broken parts).

For the last poster ......I can't see a logical reason N2O would feel weaker at the top end though. N2O has a cooling effect, whereas boost has a heating effect .....so I would think the longer you stay in it the more power you'll lose with boost compared to N2O. Many people I know locally say the nitrous cars seem to pull harder at the higher speeds as well. It's all in what you like though, I like the novelty of a blower and the fact that the power is smooth and always there. :cool:

Originally posted by BAD 97 WS-6
I see what you are saying...Will I get more power for freeway races with a blower though? It seems Boost is better for high speed runs....My nitrous dies off the longer I am spraying...thats what I hate.

Yes, the SC is great at high speeds, depending upon how it is setup, your cam, heads, etc. But the main hp gain with a typical centrifugal setup is from 3,000-4,000rpm and up and max hp gain is only at the top of the rev range for the particular combo.

Rich Krause

you can't just say for every psi you'll get x hp. Power gained from boost is not liniar, for every additional pound you get a little less power then you got from the previous one.

That being said, I don’t believe that you ever clarified where you’re at now, what kind of blower and if it’s intercooled, so making a guess, lets say you’re making 300rwhp on a 90* day, with a compressor at 75% adiabatic efficiency you could expect about 75hp gain, add an intercooler that’s at about 75% efficiency it becomes 105hp gain.

I ran nitrous for a year before I installed the blower. I do love the sound and attention of the blower, and I love the way it pulls at high rpm's. But is my car faster than it was running a 125 shot of nitrous? I don't think so, and I know I do miss the KICK of nitrous when it came on at about 3K rpms.

That jammed in your seat feeling with nitrous is great fun, but I did get tired of messing with that stupid bottle and finding refill stations.

And yes, temperature does play a huge role in supercharger cars, even intercooled ones. I know my car runs well in 100 degrees, but it is extra wicked in 40-50 degrees. It just eats that up!!

Mike M

Go turbo ;) . You get the torque of N20 and top end of the blower and then some....hehe

Jose

gotta love the turbo or turbos;)

I would love if a Twin Turbo Kit existed for a camaro

most twin turbo kits have to be custom made. If you can get some headers made to fit your car, the rest is pretty basic. Most newer cars are tight on room, though, but anything is possible for enough money.

That is the point.. its a lot of money...

turbo lag is like a sluggish auto transmission - u stomp the gas n u get the power (downshift) 2 seconds after u wanted the power. i dont like turbo's, I also don't like sloppy auto tranny's, I like nitrous, superchargers and manual valve body tranny's :) ofcourse, ive never driven nitrous + turbo combined, NOS say it eliminates turbo lag, but thats not something u wanna do on the street all the time just to pass someone.

Nitromethane-
with a properly sized turbo there is basically no lag.

my turbo is kinda bigish(950hp) but it makes 8psi by 2500, and any rpm above that the boost is basically instant.

its like nitrous, all the time!

Originally posted by JordonMusser
Nitromethane-
with a properly sized turbo there is basically no lag.

my turbo is kinda bigish(950hp) but it makes 8psi by 2500, and any rpm above that the boost is basically instant.

its like nitrous, all the time!


gotta love that :metal: :D

mmmmmmmmmmm nitrous. I could run nitrous all the time yanno.... but I dont have $2000 to spend on n2o bottles ;)