boost=hp

[Busa1166]

Have a question figured our people running turbo's would be a better source. Guy we shall leave the shop nameless claims he can get 450hp from an RCC kit with 12 lbs of boost??? Haven't met to many guys with turbos but the 2 that I know are running more like 20-24 lbs of boost to get those kinda numbers. Are my friends dealing with bad tuners and installers, or is this guy some kind of tuning genius???


My other guess is this guy is full of **** an I should keep looking for someone else Not saying he is mind you just having a little trouble swallowing what he is shoveling that s all

Like to hear from the opinions of the dyno tuners here also they deal with this non stop an even tune installs done by others

 

[Mr Bogus]

50% increase in torque for first 7-8 psi.. on a really good system 47% increase in the next 7-8 psi (intercooler, water injection etc to cool air charge down)

So he would need to be making substantial HP off turbo.. say in the area of 250-275 hp off boost.. Not saying it is impossible but sure is a tough number to buy..

 

[cdhoroho]

i call bull
on a 70 mm turbo we are seeing about 15 hp/pound of boost max
and on average they say 10-11 hp/ pound of boost for the average kit

 

[DropBusa]

concur with above post.

Heres some simple math for ya.

450hp-160hp(stock motor)=290 horse thats gotta be made. 290hp / 12 lbs of boost = 24.1 horse per pound of boost. NOT GONNA HAPPEN!!! I'm running a 70mm turbo and makin about 15 horse per pound. your not gonna fit much more of a bigger turbo on a busa. Even if it is an ULTRA kit, your not makin that kinda power.

I'd like to know the shop and id like to know if Richard knows about his kits doing that kinda stuff....

 

[ogre]

it's all about airflow. if you have a turbo that flows ~45 lb/min at 12 psi, then yea, it's possible. for example, don't worry about when this turbo will spool on a stock displacement/compression busa. this is just about airflow for a minute.

now, how to read compressor charts 101, in a nutshell. the column on the left is pressure ratio. pr=a+b/a, where a= atmospheric pressure (call it 14.7kpa) and b=target boost, so 12. now 14.7+12/14.7=1.748. so draw an imaginary line at 1.75. now the bottom row is lbs/min airflow, 1 lb per minute of airflow is approximately 10 hp. there is a formula to calculate hp from lbs/min but it's so close to 10 almost all the time that it's not even really worth mentioning. so anyway, at 45 lbs/min, the theoretical engine output, assuming that your tuner doesn't blow it up, and assuming the stock head can flow that much air, it's entirely possible to make 450hp with say, a gt4094 (almost a gt42, and before you ask, yes, it's big.). now comes the rub, when will the busa spool that monster turbo up to 12 psi? hell, WILL IT spool a 4094? i'll let someone with more busa specific knowledge field that one, but i figured i'd kick in some turbo freak speak just to get us going.

 

[theskaz]

k...im wet

 

[ogre]

alright, part two. the reason you can't compare boost to hp is that boost doesn't make hp. airflow does. for example, lets say a stock head flows, i dunno, 45 lbs/min, and an aftermarket head can swallow 50 lbs a min at the same boost level. now if your turbo is capable of flowing 50 lbs/min at 12 psi, you'll make 500 hp. you can also make the same hp as stock, with lower boost. think of it this way, boost is a measure of restriction, it's how much air the turbo flows vs how much air the head flows. you could run a bajillion psi, but if the motor will only swallow 30 lbs/min, you are limited to 300 hp. if the motor can flow tons of air, you can make tons of hp if you add appropriate amounts of fuel. of course this assumes your tune is good, motor doesn't pop, but you get the general idea.

 

[cdhoroho]

alright, part two. the reason you can't compare boost to hp is that boost doesn't make hp. airflow does. for example, lets say a stock head flows, i dunno, 45 lbs/min, and an aftermarket head can swallow 50 lbs a min at the same boost level. now if your turbo is capable of flowing 50 lbs/min at 12 psi, you'll make 500 hp. you can also make the same hp as stock, with lower boost. think of it this way, boost is a measure of restriction, it's how much air the turbo flows vs how much air the head flows. you could run a bajillion psi, but if the motor will only swallow 30 lbs/min, you are limited to 300 hp. if the motor can flow tons of air, you can make tons of hp if you add appropriate amounts of fuel. of course this assumes your tune is good, motor doesn't pop, but you get the general idea.

by the way you need a little more busa knowledge (not tryin to knock ya)
i know someone with a gt4094 that is making 330 at 15 pounds of boost (rcc super ultra kit)

 

[cdhoroho]

oh and by the way yes i know how to read a flow map and yes i understand is more of a flow of air vs boost pressure but most would understand an increase of boost pressure vs hp increase to understand how much power they would make

 

[ogre]

if he's only making 330, it's not the turbo that won't flow the air, it's the head. as far as busa motors go, they're not any different from any other 4 stroke gasoline motor, they're all basically the same. anyway, 330 is a ton of damn power for a 1.3. to do a psi>hp guess, you'd have to assume quite a bit, but since everyone is running basically the same motor, i suppose we can do that. generalizations sometimes lead to misunderstandings, and i prefer to avoid those altogether. just kinda wierd that way i guess

 

[Busa1166]

wow thanks for the input guys or gals

 

[Johnnycheese]

it all depends on what you have to start with 7# on mine made 320 but I am not stock

 

[Mr Bogus]

it's all about airflow. if you have a turbo that flows ~45 lb/min at 12 psi, then yea, it's possible. for example, don't worry about when this turbo will spool on a stock displacement/compression busa. this is just about airflow for a minute.

now, how to read compressor charts 101, in a nutshell. the column on the left is pressure ratio. pr=a+b/a, where a= atmospheric pressure (call it 14.7kpa) and b=target boost, so 12. now 14.7+12/14.7=1.748. so draw an imaginary line at 1.75. now the bottom row is lbs/min airflow, 1 lb per minute of airflow is approximately 10 hp. there is a formula to calculate hp from lbs/min but it's so close to 10 almost all the time that it's not even really worth mentioning. so anyway, at 45 lbs/min, the theoretical engine output, assuming that your tuner doesn't blow it up, and assuming the stock head can flow that much air, it's entirely possible to make 450hp with say, a gt4094 (almost a gt42, and before you ask, yes, it's big.). now comes the rub, when will the busa spool that monster turbo up to 12 psi? hell, WILL IT spool a 4094? i'll let someone with more busa specific knowledge field that one, but i figured i'd kick in some turbo freak speak just to get us going.

yea now just get a correctly sized turbo... T4 series turbo on a 1.3L motor? good friggen luck getting that thing moving... Might be possible but you better have the length of Bonneville to get it going cause it is going to take a lot of effort.. MIGHT be able to squeeze the housings down far enough to make it work on a 2L motor.. We have used something similar on the BGN upgrades.. Using the T4 guts with the T3 housings...

 

[ogre]

not gonna lie, i picked that to demonstrate the lbs/min, not the turbo i'd pick. if i were picking a turbo, i'd do a bit more research about airflow through the head. and i'd honestly probably pick a bullseye turbo rather than a garrett. maybe an hks if i didn't have to pay for it.

 

[Destin07]

i don't really know alot about acutally turbos housing and how to interpret the #'s but i have a GT4094 on my bike and i've only put 500 street miles on it but it works pretty great I think, it has the twin scroll RCC manifold and i'm sure thats a huge part but i don't really even notice the large lag that everyone was warning me about. Comes on rather well in my opinion

 

[Mr Bogus]

i don't really know alot about acutally turbos housing and how to interpret the #'s but i have a GT4094 on my bike and i've only put 500 street miles on it but it works pretty great I think, it has the twin scroll RCC manifold and i'm sure thats a huge part but i don't really even notice the large lag that everyone was warning me about. Comes on rather well in my opinion

not sure what the "RCC manifold" is about but if you put a tight enough housing on the hot side, you can make just about any turbo work but then you get other 'issues' to deal with.. a TO4 on a 1299cc motor sounds pretty tough to me.. I would like to see some runs on the track to see how it is coming on and charging on the big end..

Compressor maps as above are pretty important when building/designing but are just about worthless if you have the wrong sizing of wheels and housings in the first place for engine displacement..

The physics of turbo charging (or any other positive pressure devices) are pretty simple.. double the A/F mix available to the motor and you might make double the HP.. (a gallon of fuel only has so much energy) The problem is "heat" (kills air density) so a turbo that is sized correctly tends to heat the air less.. But it can not create HP out of nothing.. (this all goes away on exotic fuels btw)

Got some guys with a lot of practical knowledge here at least

My choice of turbo for a build might actually be a Mitsubishi ceramic wheeled variable vane unit.. (spools ultra ultra fast but not great for making GIANT dyno numbers and are $$$$)

 

[Destin07]

not sure what the "RCC manifold" is about but if you put a tight enough housing on the hot side, you can make just about any turbo work but then you get other 'issues' to deal with.. a TO4 on a 1299cc motor sounds pretty tough to me.. I would like to see some runs on the track to see how it is coming on and charging on the big end..

Compressor maps as above are pretty important when building/designing but are just about worthless if you have the wrong sizing of wheels and housings in the first place for engine displacement..

The physics of turbo charging (or any other positive pressure devices) are pretty simple.. double the A/F mix available to the motor and you might make double the HP.. (a gallon of fuel only has so much energy) The problem is "heat" (kills air density) so a turbo that is sized correctly tends to heat the air less.. But it can not create HP out of nothing.. (this all goes away on exotic fuels btw)

Got some guys with a lot of practical knowledge here at least

My choice of turbo for a build might actually be a Mitsubishi ceramic wheeled variable vane unit.. (spools ultra ultra fast but not great for making GIANT dyno numbers and are $$$$)

its just a twin scroll manifold, only other turbo i ever rode was a rcc stage 2, it didn't spool terribly sooner and this GT4094 pulls much harder, but it might just be my setup...i run a 240 rear tire, i weigh 270, bikes slammed down and 6 over, but you can wind it out and it wont get wheel hop or spin till 10K in 3rd and 4th at 15-18lb....so its not just blowing the tire off all over the road, its quite the opposite of what everybody told me it was going to be like

 

[Mr Bogus]

its just a twin scroll manifold, only other turbo i ever rode was a rcc stage 2, it didn't spool terribly sooner and this GT4094 pulls much harder, but it might just be my setup...i run a 240 rear tire, i weigh 270, bikes slammed down and 6 over, but you can wind it out and it wont get wheel hop or spin till 10K in 3rd and 4th at 15-18lb....so its not just blowing the tire off all over the road, its quite the opposite of what everybody told me it was going to be like

Without getting too specific.. I would rather see some 1/4 mile times to see what the machine is really doing.. Not to discount anyones sense of "Feel" but there is no such thing as a butt dyno that is really accurate.

If it goes out there and runs 8's then I would be looking at the turbo combination but my guess is the bike may get trounced by a stocker in the 1/4 mile. (have seen a number of turbo bikes annihilated in the 1/4 by stockers) Dyno mules do not necessarily make good or fast rides...

by the way, we use that exhaust housing (split opening) on the diesel kits we built and sold for a long time (.95 and 1.05s on the T04 made 7-15lbs of boost depending on fuel load) and they did not really do anything special that I could see on the rollers. (different application so may not have any relation to the same housing on a gas motor)

 

[cdhoroho]

the 4094 is more of a LSR turbo
they go with a t61 or gt35r for drag racing
his makes huge power and makes it fairly quick (ive seen the dyno graphs)
and it will do descent in the 1/4 but not set the world on fire
but its not just a turbo that makes the times in the 1/4 its chassis and clutch
if you were to throw his setup on my bike it would go 7's as my chassis is setup for it but i am going with a t61 (to keep in the rules of my desired class

 

[ogre]

personally i think a 3076R or maybe a 35r if you're nuts would be about right. the 4094 was just the first one i clicked on. i'd actually been considering one for a supra (same as the hks t51 series)