question for Sean

[Brazen6.0]

Twin turbo(ing) the BB, what size turbo would I need? and can I do it dirt cheap?

thinking using a blow thru carb and hat, with a small innercooler up front, 2 turbos, mounting shortie headers upside down....about 6psi boost (motor is 10-1 alum heads, should be ok, with head studs)...and a boost retard inginition box...and an elect fuel pump (7psi na, but with 6 psi boost I will need 15psi of fuel pressure)

If I can do it for less then 800 bucks, I might concider that VS nitrous.

key word is "welfare-racing" cheap!

[Brazen6.0]

also, a single turbo might be better I don't know....

let me know brotha

[Ed]

:whoa:

[toastychicken]

Something wicked this way comes:evilgrin:

[4U 2 NV]

using little money will probably get you little power. just spray it. or dont save up for a procharger.

[HORSEpower]

Single T-76 or bigger.

Kurt

[toastychicken]

I think the eventual plan, as he mentioned, is to spray AND boost it. And run 8's.

[Brazen6.0]

nop, it'll cost 1k to put nitrous on my car (by the time you get all the little odds and ends), I want to see what a turbo set up would cost me to add 200hp to my motor...knowing that with C16 I could go alot more hehehehe

[Grannynational]

JB, you will need an T88 or bigger to do the job right. If you are totally in for wellfare racing, Buy a used turbo, and yes go with a single setup, or two if you can find two smaller ones cheaper, plum it up with mandrals and exaust pipe. I would build a sealed box around the carb as apposed to a blow through setup, and at 6psi you wont need an intercooler, not making a lot of heat.

It can be done for $1000, but there would be a lot of labor and it wouldnt look all that pretty under the hood, but it would haul ass.

with all that being said, turbo vs nitrous vs Vortec for carb setup.

I'd save your $$$ and get that vortec for the carb set up. see last years car craft when they put it on a 454 and picked up a 35% power increase without touching the carb.

Joe

[TheSean]

well no turbos that you can afford can be put on single, you need such a huge compresor to keep up with the flow of your motor.

Im trying to find if any at all will, or if you will have to use 2.

[HORSEpower]

There are plenty of turbos out there that are big enough. Keep in mind that he is only looking to make 6 psi. The static compression of the motor is too high to run much more.

Kurt

[Brazen6.0]

I see

[TheSean]

JB you suck. your engine flows too damn much, haha.

I put a T88 on the flow map, and it works REALLY well until 5000rpm, when your motor will actually suck the thing dry :eek:

Ill also insert that at 2bar, which is 14psi, at 7000rpm your engine consumes 1600cfm :eek:

at 6000rpm and 10psi, 1141cfm
at 6000rpm and 5psi, 883cfm
at 6500rpm and 10psi, 1236cfm
at 6500rpm and 5psi, 957 cfm

6psi:
3000rpm (prespool/spool): 538 cfm -- 47.2 lb/min--512 hp
4000rpm: 717 cfm -- 62.9 lb/min -- 683 hp
5000rpm: 897 cfm -- 78.7lb/min -- 854 hp
6000rpm: 1076 cfm -- 94.4 lb/min -- 1025hp
6500rpm: 1166 cfm -- 102.3 lb/min --1111hp

That is at 90% volumetric efficiency, theoritical flow, and using 10.86 as the mass index of volumetric flow (cfm to lb/min) which means its not incredible hot. Also, hose calculations do not account for the temperature rise in the air compression, hat is intercooled, assuming no drop in pressure due to intercooling, no paratic loss from the IC (100% efficiency of the IC), no restriction before the turbo (no air filter) and a steady-state process inside the cmbustion chamber (90% VE through powerband).

Hence, those are the theoretical maximums. Not bad for 6psi :) oh, and just in case you accidentally revved to 7000 and ran 14psi, youd make just over 1500hp. That requires 120 gallon/hr of fuel at a 12:1 air fuel ratio.

Conclusion: you have to run 2 turbos. Ill upload the maps tomorrow so you can see what im talkin about.

[Brazen6.0]

that's insane! and I like it!

[TheSean]

one GT60 or two GT42s will work. You can get the GT42s in single or dual ball bearing option! That means spool at like 3000rpm :p

[Grannynational]

ball bearing turbos are not cost effective, we're thinking junkyard stuff off of a powerstroke, or a diesel truck.

Joe

[TheSean]

disesel burns too cool, thats not really a solution.

[TheSean]

http://expha.com/CTECH/SHOP/work/turbo/JB-489.3/T58.jpg

http://expha.com/CTECH/SHOP/work/turbo/JB-489.3/T88.jpg

http://expha.com/CTECH/SHOP/work/turbo/JB-489.3/TSo4%20(T58).jpg

http://expha.com/CTECH/SHOP/work/turbo/JB-489.3/gt37.jpg

http://expha.com/CTECH/SHOP/work/turbo/JB-489.3/t61.jpg

http://expha.com/CTECH/SHOP/work/turbo/JB-489.3/t64.jpg

[customcarmaker]

ok im not all that informed about turbos so i have a couple questions. one, if jb ran two turbos what is the difference between running them in line off both headers or running just one per header and not not connecting the two sides? or am i just confused because in line 6s can run twin turbos off one side obviously?

[toastychicken]

If you ran them in line, wouldn't the second turbo have a ridiculously high turbine speed? And I'd imagine the heat through the second turbo would be crazy high too. Not to mention the piping. Sean?

[HORSEpower]

ok im not all that informed about turbos so i have a couple questions. one, if jb ran two turbos what is the difference between running them in line off both headers or running just one per header and not not connecting the two sides? or am i just confused because in line 6s can run twin turbos off one side obviously?

Cars like Supras and RX-7s have sequential turbos. They both run off a single exhaust source. Only one turbo spools up at low rpm, and when it hits high rpm the second turbo spools up. It reduces turbo lag.


Kurt

[Ed]

Thassa smaht neegah.

[Brazen6.0]

the question was asked to Sean...anyone highjacking my thread and having a pissing match will get his ass banned....

[TheSean]

thanks JB...

now you can see what turbos would be viable. im now mapping the GT40 and GT42. You would use two of them. I may start denoting the actual engine #s on the maps, for sanity's sake, but you can pretty much tell that if the chart says 55lb/min its a twn setup and if its ~ 110+ lb/min its a single.

[Ponyperformance6]

well no turbos that you can afford can be put on single, you need such a huge compresor to keep up with the flow of your motor.

Im trying to find if any at all will, or if you will have to use 2.


ahh boo, just go to a heavy machinery junkyard and take the turbo off of a CAT diesel.... you wouldn't make much boost, but that CFM would be through the roof. :whoa:

[Ponyperformance6]

JB you suck. your engine flows too damn much, haha.

I put a T88 on the flow map, and it works REALLY well until 5000rpm, when your motor will actually suck the thing dry :eek:

Ill also insert that at 2bar, which is 14psi, at 7000rpm your engine consumes 1600cfm :eek:

at 6000rpm and 10psi, 1141cfm
at 6000rpm and 5psi, 883cfm
at 6500rpm and 10psi, 1236cfm
at 6500rpm and 5psi, 957 cfm

6psi:
3000rpm (prespool/spool): 538 cfm -- 47.2 lb/min--512 hp
4000rpm: 717 cfm -- 62.9 lb/min -- 683 hp
5000rpm: 897 cfm -- 78.7lb/min -- 854 hp
6000rpm: 1076 cfm -- 94.4 lb/min -- 1025hp
6500rpm: 1166 cfm -- 102.3 lb/min --1111hp

That is at 90% volumetric efficiency, theoritical flow, and using 10.86 as the mass index of volumetric flow (cfm to lb/min) which means its not incredible hot. Also, hose calculations do not account for the temperature rise in the air compression, hat is intercooled, assuming no drop in pressure due to intercooling, no paratic loss from the IC (100% efficiency of the IC), no restriction before the turbo (no air filter) and a steady-state process inside the cmbustion chamber (90% VE through powerband).

Hence, those are the theoretical maximums. Not bad for 6psi :) oh, and just in case you accidentally revved to 7000 and ran 14psi, youd make just over 1500hp. That requires 120 gallon/hr of fuel at a 12:1 air fuel ratio.

Conclusion: you have to run 2 turbos. Ill upload the maps tomorrow so you can see what im talkin about.


No.... just one stupidly massive turbo that only makes a few pounds of boost but flows enough CFM to suck the air out of a room in 3 seconds flat

[Ponyperformance6]

Cars like Supras and RX-7s have sequential turbos. They both run off a single exhaust source. Only one turbo spools up at low rpm, and when it hits high rpm the second turbo spools up. It reduces turbo lag.


Kurt


That, and they have only one exahust exit, so you pretty much have to do it that way. Running twins would reduce turbo lag anyways,that is usually the biggest reason for doing so, but as Sean pointed out, JB will be pushing so much air that spooling shouldn't be a problem.

[TheSean]

will, contrary to common intuition, twins wont neccesarily spool any faster than a single. Unless you run a complicated system like the supra, you just have to dealm with the lag that comes with higher air flow. Nitrous is the way around this, and always emember, theres only lag in 1st gear :)

JB does indeed either have to run 2 turbos or pay about 2500 for one with enough low end flow to fit is engine. Maps coming for the GT42, T100, T91 and GT60 turbine. It takes about 1/2 an hour of math work per map, then another 45min of photoshop which i can cut down to about 10 by making a few variables constant. I wish i was there, because it'll take a LONG time for me to type up exactly what and why im doing all this, and why you have to do research on a turbo before you slap it on. Anyhow, thats later.


Sean

[Cracker Red]

www.turbocalculator.com has maps online, as does www.limitengineering.com, Garrett, turbonetics, etc.. I don't see where the 30 mins worth of work is on a map, unless you are thinking about how the map is layed out everytime you look at one. You need to find out how much HP you'ld like to make, what your motor will pump out VE wise, what you think the BSFC ought to be (easily found), and select a couple of wheels and AR's. Done. Takes about 5 mins looking at the catalogs to figure out what would work best, and then perhaps a few more moments getting the best financial solution. 2 turbo's = more components, more weight, more hoses, etc..
2 turbo's will spool faster if sized accordingly, due to reduced mass of the wheels, increased VE on the turbo's part, etc.. 1 turbo is what I would go with, 1 big, giant, snail under the hood. Look for a 5" exhaust pipe to come out of it.

[TheSean]

since when is one wheel less than 2?

also, look at my maps (posted above) and the ones on RRE. Not as if they even make flow maps themselves, but rather just steal them, you might notice some plotting on mine ;)

It's specific to JB's motor's air consumption (estimated, as usual). Its pretty much vital to FITTING a turbo to a motor. Id love to know what way YOU do this :)
since you dont know what a EDL is.

[HORSEpower]

Generally 2 wheels is less mass than one. Doesn't matter. One really good turbo is better than 2 anyway.

Kurt

[TheSean]

how can you possibly state that 2 wheels is less than 2??????????????

2 is more than one. The center part of wheel is where most of the mass is, and the differece between a big wheel and small wheel is not even close to 1/2, let alone 60% +. where are your #s on this?

2 16 inch wheelsweigh more than one 19inch wheel of the same basic design for your car.

[HORSEpower]

You tell me. Show me 2 turbos adding up to the flow of one single, and their total rotating masses. The efficiency of the impellar is the key element anyway.

Kurt

[Cracker Red]

One turbo for max power, simplicity, etc...
2 may have slightly better spool, tractability, etc..

Most of the big dog import guys running RX's and supras go with one turbo..

[TheSean]

why does one spool faster than two?

[TheSean]

You tell me. Show me 2 turbos adding up to the flow of one single, and their total rotating masses. The efficiency of the impellar is the key element anyway.

Kurt


i can find anything on rotating mass, id have to call a company.

Garrett:
GT35: 42 lb/min
GT42: 95 lb/min

One GT35 spools around 3700, one GT42 spools around 4200. Two GT35s would be laggier than one GT42. Go look at the dyno charts. I dont think anyone is running two GT35s that i know of, but plenty of people are running big twins, and you know theres tons out there with singles. Also, did i mention cheaper? Usually about 1-2000 less for a single flowing the same amount.

the efficiency of garret turbos are always close, so just compare two of them, and compare the performance. Singles are the way to go for most people.

[HORSEpower]

Oh, I would definately go single, but I concede there are certain twin combinations that will spool better.

Kurt