RoadHammer

...are you all running for turbos?

I am building a 383 stroker with Twins and having a difficult time deciding what to go with in terms of turbos.

browncamaroz28

iTrader: (1)

PM me with the max hp you want to have, the max rpm your going to spin, and i'll do the calculations for you.... they will give you a rough area to start with...

RoadHammer

PM sent.

83 Crossfire TA

iTrader: (2)

woudn't it be more useful to post the info publically so you can geti more then one input....

sleepybu

browncamaroz28

iTrader: (1)

he can post it if he wants, he was going to get two gt40r's to make 800 hp at 6000rpm, so i did all the calcs and told him to get gt3582r's to make that but have better spool.... at about 11psi

RoadHammer

Here is Browncamaroz28's Turbo calc, and I concur with the findings.

Based on a 383, with max of 6000rpm, producing ~800 hp......

Ok 800hp requires no less than 80lb/min air so to keep the turbos from over spinning go with a total of 100lb/min.

CFM = CID x RPM x VE ÷ 3464 to find cfm so you need 663.39cfm n/a at about 1 VE

lb/min ÷ 0.07 = cfm boosted so = 1142.85cfm

Cfm boosted ÷ Cfm unboosted = pressure ratio

1142.85 ÷ 663.39 = 1.722 pressure ratio

(14.7 + Boost)/14.7 = pressure ratio

(1.722 x 14.7) - 14.7 = 10.62psi at 6000rpm to get 800hp...

The recommended turbo in the Garrett GT series is the GT3582R, (although in the Garrett catalog they call this the GT40R, but my catalog pdf maybe a couple years old. )

sleepybu

what would be a turboneticsinc equivilent

browncamaroz28

iTrader: (1)

Yeah i think you may have an outdated catolog, but your definately on the right track. So how are you going to contruct the manifolds or are you going to buy a set?

RoadHammer

Sleepybu
I am not sure about Turbonetics, prolly somewhere in the T-series with ball-bearing option cuz the GT3582R is a ball-bearing turbo.

As for manifolds, I was thinking of 1 of 2 options.....

1) Go junkyard diving and find a pair of stock mainfolds and flip them so that they discharge towards the front. If they fit, I'll clean them up, get them extrude honed and make an adapter to attach the turbos to the ends. I read somewhere that some guys where trying this with some success.

OR

2) Go all-out and fab up some custom inconel or some hi-temp stainless manifolds.

If I could buy turbo mainfolds that were MADE for the third gen I would but I have not seen any worth looking into.

browncamaroz28

iTrader: (1)

My vote is for some custom fabed ones.... stock log style are great for stock cars, but if you want some serious hp, you won't want any flow problems and the poor heating patterns that the log design causes....

84camaroturbo

mine are paceseter headers up side down for a 97truck cut the end off and fabed the 3inch and flange for it. then sent off and got them nickel plated.

browncamaroz28

iTrader: (1)

I've seen setup like those before and they look like they would work really well... my setup for my single turbo is a set of edelbrock shorty's going to a y pipe to one collector and then the turbo... with the paceseter's its probable in the same flow range...

FSTFBDY

iTrader: (33)

84camaroturbo and browncamaroz28
got pic's. of your setups?? send me a PM so I don't hijack this thread.

junkcltr

iTrader: (1)

I have seen some good HP numbers with stock log headers. Since you said they don't flow and have heat problems I would like to see the data that backs that up. I have never heard or seen any of those problems. New data is always good. Custom fabbed ones are worse than stock style depending on the layout.

FSTFBDY

iTrader: (33)

bands seems to make good power with there TT kit and logs. as do many people on here and other sites.

but if you can afford it Go for it with a custom setup.

junkcltr

iTrader: (1)

Yeah, those will work but many other turbos will work from production vehicles just as well and cost half or less. Better get out the wallet for them bad boys. BB turbos have their place, but for a street car I don't seen the point or the price.

browncamaroz28

iTrader: (1)

if you have the money BB is where its at, i for one don't, i have a standard journal bearing. As for the log headers, sure people make good power on them, but its proven that tube style headers will make more power. And its obvious that he's not going cheap on the turbos so why go cheap on the headers which are equally important. My vote is, if you have the money, do it right the first time....

junkcltr

iTrader: (1)

It isn't that obvious to me that he wants to spend a lot. He says in one case that he will do a dumpster dive for some used manifolds (approx. $000) and the other is Iconel ($1000). That is a huge difference. I am guessing his turbo setup will range from a couple of used TO4s ($100 each) to GT BB series ($1500 each).

The other strange thing is that a few posted they are using thin walled (18 - 16 ga.) mild steel and no one has told him to build them stronger for a real street setup. Thin wall mild steel is good for the track but not that good for the street in terms of durability and heat retention. Heat = energy = power = spool_time. Having manifolds/headers that hold heat, the proper ignition timing, and correct A/R are much more important than having a Ball Bearing turbo when it comes to spool time.

browncamaroz28

iTrader: (1)

yeah when did we start talking about fuel and ignition tuning? you just like to make a big fuss about everything now don't ya

gta324

I'll hijack the thread some.... I'm thinking of TT for my 415" next winter and I know nothing about turbos, yet. But I have started to look for TT at Ebay, just to get a feeling for price range and availibility.

http://cgi.ebay.com/ebaymotors/TWIN-...spagenameZWDVW

http://cgi.ebay.com/ebaymotors/TWIN-...spagenameZWDVW

any thought about these?

84camaroturbo

if i can find some pics i will send them. my car sees the track maybe twice a year all the rest is done on the street and daily driving and havent had a problem with my headers and i also put down 716foot pounds to the wheels at low boost dont know at high boost.

83 Crossfire TA

iTrader: (2)

How about we start with this, what the hell is a “poor heating pattern?”

I’ve yet to see anyone come up with convincing data if you take in the context of what is actually going on. In other words, you’ll sometimes find someone that has actual data that showed a car going faster/making more power by swapping to tubular headers, but only when they were running a grossly undersized turbine for the application, which just indicates that the tubular headers are loosing more energy (less efficient) and allowing them to get away with the undersized turbine side.

This does at least assume a decent log design with some consideration to flow direction…. There is quite a bit more to the most efficient turbo header/manifold design, but I can’t think of any quality that is exclusive to tubular headers that is actually an advantage in a turbocharged application.

Where do BB turbos have their place? There really is only one place they were developed for, and that’s for a small displacement engine that has problems generating enough exhaust energy to spool up an oversized turbo (for example, a 1.6L Honda with a large Txx turbo). On any kind larger engine with a better sized turbo it’s hard to demonstrate any performance improvement with BB, and rarely are they as durable.

“standard” turbo bearings are full floating or semi floating sleave bearings, which are quite different then a journal bearing.

Proven… Ok, how about some hard, useful numbers? I’d be willing to accept it if there was any evidence for it, but I haven’t seen any.

83 Crossfire TA

iTrader: (2)

As far as the listed numbers… you’re assuming 100% VE, 100% adiabatic efficiency and 100% intercooler efficiency (assuming you’re running an intercooler). At the same time you way overestimate the amount of air needed (you can make 800hp with around 73lb/min of air), which does cover up some of your ambitious efficiency numbers, but no matter what you’re looking at a higher pressure ratio/boost to make the power, which conveniently usually allows for slightly smaller turbos.

That being said, even something like a pair of GT32s will get you there, and smaller turbos might be a better choice on a street car, and something like a GT3576 or a T61 would work nicely in a race application (making peak power in the center, highest efficiency island of the compressor map).

Junkcltr, I don’t know what “production vehicle” turbos you had in mind, but this is sort of the sweet spot for smaller diesel turbos so there is plenty of fodder there if you know where to look.

83 Crossfire TA

iTrader: (2)

Why don’t you start a thread with pictures and details? I don’t know of another vortech headed turbo car running around here yet…

84camaroturbo

it is sad that i have had the car turboed for about 5years and dont have one pic i can find of the motor in the car. the heads now are e-tec i ran the vortec for 3years. motor tore down for the winter shooting for 1000rwhp this summer at 19psi. i will see if i can get my dyno vid posted.

sleepybu

whats the specks on the turbo(s)???

84camaroturbo

they started out as to4b with a 60 on the inlet and 1.60 exhaust but have been modified i had a place put different compressor wheel and inlet dont remember right of hand then put .98 on center exhaust housings on it.

askulte

If you're at 800hp at a 1.722 pressure ratio, doesn't that assume that your engine will be 800/1.722=465 hp naturally aspirated? This might be challenging for an 8.5:1 compression engine running a smaller turbo cam and a restrictive (compared to longtubes) exhaust. I've always worked the calculations the other way, entering the pressure ratio, and using that as a % hp increase from the base engine, and going from there.

Airflow=cid * rpm * .5 * VolE / 1728 = 383*6000*.5*.85/1728 = 565 cfm naturally aspirated.

Multiply that by the 1.722 pressure ratio, and you get 973 cfm, divided by two, and it's 468 cfm per turbo at max boost redline.

To get the actual pressure ratio for the engine, you have to calc the turbo & intercooler efficiencies at your pressure ratio, airflow, and intercooler air speed (Spearco had good efficiency charts on their cores for 5-20mph airflows).

I'm curious how you guys figure 80 lb/min (or 73 lb/min) is 800 hp.

browncamaroz28

iTrader: (1)

askulte that might be a better way to do it to be honest with you. The real difference between our calc is the VolE, i just assume VE as 1 to make it simple because as we all know some people run pretty serious cams on turbo cars (i see alot of dsm's like that) not so much v8 guys though. As for finding the lb./min its just roughing it. and then looking at the manufacturers spec.s in comparison. Oh and in reply to the whole thing on log headers, go read maximum boost or a fluid dynamics book or even a thermo book... it would be too long to explain on the forum.....

FSTFBDY

iTrader: (33)

Book world and real world experiences are like comparing apples to oranges.
Just because one guy makes more with tubular headers doesn't mean he couldn't have made the same with log style manifolds.

I'm sure theres a few HP/TRQ to be made with tubular headers. For the average joe here on these boards Id be 90% confident to say its not worth the price diff. to 50% of the people who plan/want/are doing turbo setups. The price Diff. in Tubular VS LOG style could be well spend elsewhere like a efficient FMIC, better fuel system,etc...

83 Crossfire TA

iTrader: (2)

Yep, and about 400-420hp, which is why I was saying that you’d need a higher pressure ratio, I think when I was looking at compressor maps for this the other night I was looking in the 1.9-2 range) to get to 800bhp…

And about 700-715bhp.

Your first sentence and what I posted yesterday is entirely on the same page.

There’s so much energy in a lb of gas, you can estimate the BSFC and A/F that you’ll make peak power at with a boosted engine, do the math… I worked it out at one point, put it in a spreadsheet and had it output a quick chart.

There’s a rule of thumb out there also that 1lb/min air = 10hp, but you know what I keep saying about rules of thumb and how I despise them. Conveniently that one never quite works out if you look at dyno graphs.

Maximum boost… what a waste of what could have been a roll of toilet paper. The first half is mostly approximations and made up “facts” and the second half is only a thinly veiled advertisement for his own products.

If you want to cite a turbo book you could at the very least try McInnes, he at least has a clue and showed all the math in how he figrures things out.

Thermo… sure, where does thermo help you one bit? The more surface area of external walls the exhaust gas is exposed to, the thinner the walls (both characteristics of tubular headers vs well designed manifolds)… the more the exhaust cools and the more energy is lost to the engine compartment/less energy there is to drive the turbine. Plug that into what I said and run with it, see where it takes you. Compute the actual energy involved, sprinkle generously with some old engineering papers that studied this and you’ll never see a justification for tubular headers on a turbo app again.

BDR

406 sbc, twin master power t-70's

FSTFBDY

iTrader: (33)

Nice.. You have the SS Autochrome headers right. have you ran that setup yet? If Im thinking of the right person. (white car with awesome lookin engine bay) If so Im curious how those things are holding up??

RoadHammer

'83 Crossfire TA,

Have you built a turbo motor using log manifolds? Can you speak from real-world experience in using log-style manifolds in a turbo setup? If so, which ones do you recommend?

BDR,

Is your car a street car or a track car? I was thinking of twin master power 62-1's at one point.

askulte

I'm not Mark (83 Crossfire), but I have stayed at a Holiday Inn Express, with my Gale Banks log manifolds! The major benefit is that they are very short and compact, so you don't lose as much heat to the engine bay. Since the exhaust pulses are hotter, more energy is available to spin the turbos, and you should get a quicker spool. Drawback is that they don't flow as well as a set of good tubular headers, since the exhaust from the rest of the cylinders still has to flow past #1/#2 exhaust ports, and the pulse timing won't be as precise. Good news is that you probably won't be scavenging much with 15+ psi backpressure and a low overlap cam, so that's a non-issue for optimized street driven turbo cars (as opposed to dyno queens that don't start spooling until 5000 rpm with huge turbos). Other benefit is they don't grow like stainless does, and will be much more durable & resist cracks/blowing gaskets.

It depends when that log manifold becomes a bottleneck, but definitely not until you're past 800 hp with the Banks. You can get complete 1100hp Banks engine packages with those iron log manifolds, so at least they're decent that far (I'll see if I can get backpressure readings when I head to the dyno on Monday). Perhaps a set of tubulars might make 50 more HP at that point, but thats only 4.5% at the very top.

Other than Banks, I'm not aware of commercial small block chevy turbo manifolds... Most have been DIY, which is a great way to get started, inexpensively. Build that until you're bored with *only* 500 or 600 hp, you've learned about tuning them, and then go bigger over the winter!

sleepybu

hijacker here...

how many hp to 1 lb/min of air...

BDR

both

83 Crossfire TA

iTrader: (2)

Well, I’ve built a number of setups at this point, but I’ve never used anyone else’s manifolds so I don’t have a recommendation like that…

Andris’ response really gets at a major part of the issue… there really isn’t any real sort of scavenging going on in a turbo setup, so a manifold that would even prove quite restrictive NA isn’t a problem with a turbo setup. The banks manifolds are fairly small, in places no bigger than a decent set of stock exhaust manifolds with ports not quite facing the right way and they’ve been successfully used on setups making over 1200hp. There’s a mustang setup on the market that forces all the exhaust from the engine through a part that is 1-3/4” in diameter and is regularly used in setups making 750hp…, and I know of a setup making 2300hp that uses a 2.5” crossover pipe.

Though the major point here is that flow isn’t as important as most people make it out to be in this instance, that doesn’t mean that it should be ignored either, but on the whole heat management and getting the energy to the turbines ends up being more important.

The other side of the whole thing is the simple fact that like a lot of what is debated with turbo setups, at some point you have to admit that it doesn’t ultimately matter that much since currently either way you can make more power than the engine you’re bolting the setup to will survive anyway.

Praetorian27

iTrader: (1)

Please bro, post pics and video of this monster when you are done!!!