Whether you're seeking to reach a desired power level (for racing) or a specific boost level (on the street), first determine how much airflow is needed to reach your goal at a given engine displacement and engine rpm. A normally aspirated four-stroke engine's cfm requirements are expressed by the classic formula: VE is at least 100 percent for a turbocharged engine, so use 1.0 for VE.
Next, you need to add boost into the equation. Turbo engineers use pressure ratio (the ratio of the total absolute pressure produced at the turbo outlet divided by atmospheric pressure) instead of an outright expression of boost pressure. Compressor pressure ratios corresponding to boost levels of 10 psi and 15 psi are 1.68 and 2.02, respectively; to find other pressure ratios:
Therefore, the cfm requirement under boost would be:
Cfm boosted = Cfm unboosted x pressure ratio
In the turbo world, engine airflow is measured in pounds/minute (lb/min). To convert cfm to lb/min, a good rule of thumb for 80 degrees F at sea level is to multiply cfm by 0.07:
Lb/min = cfm boosted x 0.07
For any turbo series, the higher the A/R ratio, the better the top-end performance. The lower the A/R ratio, the better the low-speed response.
Generally on a high-performance EFI engine, every 1 lb/min of airflow is worth about 10 hp, so to find the required lb/min for a race-only application, start with the horsepower requirement, then divide by 10:
Lb/min = hp / 10
:shock: :!: :?: :idea: :arrow:
575hp at the crank(500whp). I would need 2130 cfm (355cfm per cylinder). But our heads "average" flow is 960cfm (140exhust+180intake/2=160cfm x6cyl=960).
In terms of Pressure ratio...I got 2.13 (14.7Gpsi+2psi intercooler drop+14.7baro/14.7=2.13)
OK 960x2.13=2044cfm So 2044cfm=552hp (2044x.27)??? Anyway..
143.08 lbs/min (2044x.07=143.08..)
I need 575 crank HP so...575/10=57.5lbs min. WTF...??? THat last one doesn't make sence.???
143X10=1430HP...WHOW!!!. Whats going on here? There might be a glitch on the math when converting cfm to lbs/min...and HP.
I think math is missing on the lb/min from cfm boosted.
WELL 57.5is what I need regardless. And to get almost 15psi on a big turbo that flows 55lbs/min..I need verry high rpm. 8K by another graph on the 2.8-3.1l.
This is alot of math..and the real world isn't forving.
I still got to calculate turbine corrected airflow and back pressure.!!
THen calculate charge pipe sizes, calculate intake runner lenth/size, TB, exhaust pipe size, DP size..!!!.
After that shop.$$$$$. I even found a source for Inconel pipes for exhust.
Ideas anyone?
57.5 lb/min!!!!! Holy S*@t!!!
If I were you I would look at either the GT35R or the GT40R. I really like the GT35R, but I haven't plotted anything with our numbers plugged in, but I really like the look of the compressor map, and the turbine side does't seem to shabby either. The GT35R might be just shy of what you're trying to run, so the GT40R would probably be a better choice.
GT35R:
http://www.atpturbo.com/root/maps/gt35r.htm
http://www.atpturbo.com/root/maps/gt35rturbine.htm
GT40R:
http://www.atpturbo.com/root/maps/gt40r.htm
http://www.atpturbo.com/root/maps/gt40turbine.htm
Apperently...theres more to it than I thought :shock: . I have to toss that math out the window. Its not looking good to make 500 after some more reading :cry: . Well I dunno :?: . This CFM, Pressure ratio, VE thing is getting to me :evil: .
Well..we have 189 ci..(3.1L)..I set max rpm at 8000, I assumed VE at 92 percent..i hope I'm close for my mods, set density ratio at 2.2, and got 886.30 cfm (cubic feet minute) or 25097 liters per minute.
Then I with the 173 (2.8L) I set max rpm at 9000, I assumed VE at 95percent, density still at 2.2 and got 930.00 CFM or 26335 LPM.
Well now im at lost of how much hp that is in BOSTED CFM...OR LPM.
Also...I found out that the TGP 22lbs injectors are maxed out at 216hp. Is this right. 45psi fuel/90percent duty cycle/ BSFC of .55 (if thats sounds right).
Edit::: I finaly found out how to get there. ..YUP..The 2.8l for its 8K-9K rpm capability without blowing the crank and rods. I would need exotic rods and a verry finly balanced steel crank for the 3.1 to work. Of course roller valvetrain with stiff springs. I set the 2.8 to 9000 like before..but corrected my air inlet presure from atmosthere..and pluged numbers in for mass air flow and A/F ratio..and bam..got what I wanted. Got my HP figures. :P :twisted:
Heres a link to what im talking about. Its a nice handy calculator on the net I found. http://www.stealth316.com/2-air-fuel-flow.htm
That's how I'm getting there. I'm using my 2.8 core, and I'm actually going to destroke it a hair. It will actually be a 2.6
Man a 2.8 would sound pretty amazing at 9000 RPM! You guys sound like you are really getting the numbers down...just need to find quality components that won't shatter at 9000 RPM...BIG MESS!! 8)
Yea. If I could I would have stuck with the 3.1. Im sure the TQ it would produce would be much grater than the 2.8..and I would have better times on the 1/4 mile. Well I'll see. Im still going to dog this 3.1 I have. At thise HP levels I wish I had the money for a BOW TIE block (I actualy passed one up long ago for $1K :cry: ). BUt I'll see if a Stock block could hold with a home made main girdle that extends to the oil pan bolts., windage tray, and a crank scraper. I'll be amazed if one of use gets 500 hp before anyone on the other GM forums. 8)
Quote from: TGPilotMan a 2.8 would sound pretty amazing at 9000 RPM! You guys sound like you are really getting the numbers down...just need to find quality components that won't shatter at 9000 RPM...BIG MESS!! 8)
Call Lunati. I'm stepping into some work with them to get the rods, crank, and pistons done for mine. They are also going to do my cam.
With the destroked 2.8, I should be sitting right around 790whp. Now, to get the block to hold up to that..... Shouldnt be a prob, I've seen stock DSM blocks hold similar numbers, and my Supras were all about that.
Quote from: maximageWith the destroked 2.8, I should be sitting right around 790whp. Now, to get the block to hold up to that..... Shouldnt be a prob, I've seen stock DSM blocks hold similar numbers, and my Supras were all about that.
Is that pump gas or alcohol? In all honesty I think it is completely possible to obtain serious HP #'s with a 2.8 or 3.1 or 4.3 and so on. Racing circuits prove that everyday. Just depends on your knowledge and $$ resources as to what people acheive. 8)
Race gas and lots of boost. I should be around 600whp on 93 pump gas.
Sorry to be so long in offering some help or offerings, my computer took a huge crash over a week ago and just now on-line, will still be a while before I can get to my emails fixed, might not have time to get to it until after 9/15. Did my best to fix the PC when it broke (wife killed it), then got lots of help from PC gurus but still no go, had to take PC to GeekSquad who took 4 days to get me at least going, been installing software all day and good to finally see the Internet again, though emails will take a while longer!!
Anyways, back a few years ago Ryan Falconer Racing/RFR was selling a boat-load of their 60 degree secret stash, but no one individual or group of individuals wanted to bite on this huge inventory (and Ryan would not part it out) so I nabbed it and had it shipped to me (a grand just to ship this ton+ of parts!). If you guys can wait (no choice anyways [lol] ) I will be more detailed as well check the combinations with the parts I got from RFR to see what might work but to let you know, he already did all this way back when, short-stroke, high-revving 2.8L blocks and setup with 2.6 and 2.7 inch strokes (2.9 also but that one is mine :twisted: ), but this is all the ?costly-proven? parts needed for such setups. I also have two 2.8L blocks that are O-Ringed (O-Ringing was found a requirement when pushing this much power/Peak Cylinder Pressure and these rpms; per another conversation I had with Ryan back in 1996 as well). These 2.6 and 2.7 stroke custom Billet Steel Cranks also have matched (though need to check which ones for which crank) Carrillo H-Beam Rods. Back when I bought this stuff I did some looking, Carrillo Rods custom ran over $2,000 to $2,400, same for the cranks, not sure what dollar quotes have been found elsewhere for this level of quality pieces but the price should still be up there for the real good stuff, I know too since the Moldex Billet Crank for my Typhoon was $2,100. I don?t expect to charge anywhere near that price but will need to first (get back into town) check the combo of the cranks and rods I have to see what kind of setup I can offer, oh yea, back a month ago when I thought I had time to list these on eBay, I took these cranks and rods to TPIS/Cottrell Racing and had them mag?d, balanced and mic?d, all checked out perfect, with std size bearings, all perfect stuff. I also have some Forged Cosworth Pistons but need to confirm their usage with the crank and rod combos but there is I believe two complete sets of 800-900hp Forged Cosworth pistons (as stated on the box from Cosworth/England). There are a ton of other Forged Cosworth Pistons but need to confirm their use with these cranks and rods as well as for a stock 2.8, 3.1 and 3.4 setup. Last for now (as I said, NO TIME for much else right now!!! sorry) the rod bolts for these Carrillo Rods are the ?Carr Bolts? which are rated at 285,000 PSI, the best that ARP shows in their Catalog is the ARP 3.5 (nothing to sneeze at!!) and are only rated at 220-250,000 PSI, and these ARPs run $986.96 a set, :shock: , just for rod bolts! So these are some incredible engine parts that will go for a great price, if anyone is interested/talk to you after 9/15/2004 please!!
One last thing and I got to go, if anyone is wondering who Ryan Falconer Racing is do a search and there is plenty but briefly, he ran in nearly every class (at least his engines though he was involved in most) from Offshore Power Boats, IMSA GTP, SCORE/HDRA, Stadium Trucks, CART, Rally Races, Sports Car Racing, the list goes on but not here/bye for now 8) .
Thanks
Jeff M
Quote from: TurboGTUAlso...I found out that the TGP 22lbs injectors are maxed out at 216hp. Is this right. 45psi fuel/90percent duty cycle/ BSFC of .55 (if thats sounds right).
Quick note, approximately 43 psi is what the injectors see at idle, but at 10 psi of boost we get approximately 65 psi so run your figures again BUT ALSO change the 90% duty cycle (actually supposed to be 80% for most injectors) limit of injectors to 92%, and why I say to do this is Multec Injectors can be run at 92% max (more % for very short periods such as high rpms when it's nearing the limits of "on" when "off" is too short :shock: ) where as most all pintle type can only be run 80% max duty cycle, more info for you, but do let me know what your new calcs show now!
Now, can't be here any more, its 4am and more to do at home, skip sleeping till next week :lol: !
Jeff M
QuoteQuick note, approximately 43 psi is what the injectors see at idle, but at 10 psi of boost we get approximately 65 psi so run your figures again BUT ALSO change the 90% duty cycle (actually supposed to be 80% for most injectors) limit of injectors to 92%, and why I say to do this is Multec Injectors can be run at 92% max (more % for very short periods such as high rpms when it's nearing the limits of "on" when "off" is too short ) where as most all pintle type can only be run 80% max duty cycle, more info for you, but do let me know what your new calcs show now!
270ish HP. Not bad. 280 with the 24lbs after makets. A little on the rich side...but OK. Rich isn't too bad for boost. 10.5:1 limit.
(http://img.photobucket.com/albums/v74/donk316/Donk_316%20Uploads/Car%20Parts/215-1.jpg) Donks photo.
You wouldn't happen to have this gem would you? :lol: You take payments :wink:
Cain't wait to give the SY/Ty guys Hell!!!
Something tells me you would have to do some hood fabrication to get that under a TGP bonnet!! :lol:
Who needs a hood :wink: People are used to seeing old classic GMC 6-71 huffers poking out the hood..why not this :twisted: .
Quote from: TurboGTU..why not this :twisted: .
um because one turbocharger would have to sit in your lap while you drive and the other would stick out past the front bumper :wink:
:lol: ...never said I would leave the pipes in the same angles... :D
I just got a Big ass honking turbo. Should be good for 550hp..well thats one thing. Its a long road ahead. Im alread looking into a cam, valtrain mods.