John, and any others interested. The Doctor is in.
First thing is to know jow much horsepower you want or need to make. Fo me,
I used programs I wrote myself specifically for my car. I used aerodynamic
drag, rolling resistance and mechanical losses to determine how much horse
power I needed to accomplish my speed goals. I did this for seeveral
different altitudes with differing air temperatures and humidities. My goal
is to have a car which will run better than 200 mph, any more than that is
gravy for me. I determined that I needed about 600+ hp at the worst case.
Now having the horsepower needed, I can figure the amount of fuel needed to
meet that need. For me, 600 hp requires 330 lbs/hr of fuel. To get into
lbs/min divide by 60 and get 5.5 lbs /min.
To burn 5.5 lbs/min at a stoichmetric ratio multiply this by 14.1 for
lbs/min of air. Ok, this is 77.6 lbs/min of air.
Now find a compressor map! This is key and if you don't have it, you are
done. But in my case, I have maps for T3, T4, ect that I got off the net.
So you look at the map which is in lb/min and you see that the map has rpm,
efficiencies, a surge limit and pressure ratios. If you have a map in cfm
instaed of mass, then divide the lb/min by 0.07 to get cfm. A std T3 puts
out only a maximum of about 35 lbm/min. In my case to use T3 std units then
I have to run 2, actually I need 2.2 turbos, but rounding down = 2 or twin
turbos. Because I am at the extreme limit of the T3s I will thrash the air
pretty hard. Anyway, draw a line up from your air mass needs to intersect
the map. Try to find a map that lets you meet the air mass requirement with
the highest efficiency and lowest pressure ratio. I want to run about 15
psi so this is a ratio of 2. I go accross the map until it intersects the
air mass needs and see if it is within the map's efficiency island. In my
case, the efficiency is way down which means that I will heat the air in
compressing it because it takes a lot of rpms to develop the pressure. It
means that when my car is checked out that I will need to upgrade to a
hybrid T3/T4 unit which has a T3 turbine wheel and a T4 compressor whell
and scroll housing and back plate.
This is how I got to twin turbos. And I figured it another way: the stock
T3 will support about 350 hp in a 2.3L four cylinder so two of them will
work on a motor of approximately twice the displacement. This makes a
pretty good check.
As to your question, you might figure something like this. Hmmmm a 5.9L
diesel turns at 3000 rpm so it ought to support a smaller motor turning at
higher speed. I am not much on diesels but as I understand it they are
essentially two strokes and so fire on each stroke. If not then what
follows needs to be factored by two upwards. So a 5.9L turbo running at
3000 rpm should support a 5.9L 4 stroke at 6000 rpm. But it really depends
on the compressor map. So If you cannot get one for that specific turbo,
I'sd say you are maybe wasting your time.
I would suggest you try to find the turbo maps and look at T3 Super 60s
from Buick vehicles. Remember they turbo their Buick Grand National V6
(3.8L) so two of them should handle just about anything you asked for.
These however do not have the integral waste gates so you have to install
something.
Thats another reason I used the T-bird T3s, built in waste gate and actuator.
If your air mass requirement become so high at the upper rpm limits of your
motor, then build horsepower at a lower rpm and gear accordingly. I built a
horsepower/torque curve for my motor and then used the different drag codes
to determine what geaing would be best for my motor combination.
The Doctor has left the building.
mayf
At 07:07 PM 10/7/99 -0400, John Beckett wrote:
> Mayf
>
> Being a newbe to turbo's...I've got lots of questions. I like the idea
>of using junk yard turbo's, but I was under the impression that any given
>turbo will only flow just so much air and therefor a maximum amount of HP.
>So I guess 325 HP out of a T03 sounds like a lot. Are there modifications
>that will increase HP numbers? How would one figure the potential HP from
>say a Cummins 5.9 diesel turbo?
>
> I have also heard about Trick Flow valve guide problems...only on Chevy
>heads...but maybe the Fords are the same. Just bad guide material?
>
> John
>
>-----Original Message-----
>From: Lawrence E. & Cathy R. Mayfield <lemay@hiwaay.net>
>To: John Beckett <johnbeck@blueridge.cc.nc.us>; Lawrence E. & Cathy R.
>Mayfield <lemay@hiwaay.net>; land-speed@autox.team.net
><land-speed@autox.team.net>
>Date: Thursday, October 07, 1999 4:27 PM
>Subject: Re: Net Quietness
>
>
>>John, I am using two T03 units from 85 T-bird. I have done enough
>>calculations that show at a pressure ratio of 2 (1 atmosphere boost) these
>>will suffice to about 6500 rpm and at B'ville altitude. With the chosen
>>cam 226/210 ls 110 and compression at 8.5 all may calcs say about 650 hp.
>>Will be using World Products Senior Al heads (maybe trick flow but I hear
>>they have valve guide problems). I will have one TB hooked up and One MAF
>>but running large injectors > 55lbs/hr. Planning on SpeedBrain for ECU so
>>will have complete data logging and mod capability. As to wheels, no I do
>>not want steel wheels, I want alloy. I plan on Weld Prostars for racing but
>>I need a couple of ?? just to put it on the ground so I can roll it around
>>better.
>>
>>mayf
>>
>>At 10:03 AM 10/7/99 -0400, John Beckett wrote:
>>>Wow, that got em stirred up. Might look into NASCAR type wheels for your
>>>project. I believe they make them with the proper bolt patern, diameter
>and
>>>back spacing. What type and size turbos are you using on your Alpine?
>>>
>>>At 04:10 PM 10/6/99, Lawrence E. & Cathy R. Mayfield wrote:
>>>>Too darn quiet on the list! What's going on? Everybody mad at each other?
>>>>Or what? Did my first TIG aluminum welding yesterday. What a hoot! Looked
>>>>like a bunch of angry chickens drizzled all over it. But today, a
>different
>>>>story! I cranked the amps up, polished the weld area with a scuff pad and
>>>>went at it. Most welds pretty good (oh, I am making my own twin throttle
>>>>body upper manifold for my twin turbo setup). I mean it looks homemade
>but
>>>>not too bad.
>>>>
>>>>I need some wheels for my car. I need something 10 inches wide with 5 on
>>>>4.5 stud spacing and 6 inch (5.5 ok) backspacing. These are just to get
>the
>>>>car on some rear tires so I can determine the shock mounting height, etc.
>>>>It's already on the front tires. Anybody on the list have anything they
>>>>might part with? Oh, they need to have the 11/16 stud holes, not tapered
>>>>nuts, because I am using Mark Williams 5/8 inch studs (HUGE).
>>>>
>>>>Well, this otta be nuf to start some conversation...especially my welding
>>>>expertise.
>>>>
>>>>mayf
>>>>
>>>>
>>>>
>>>>L.E. Mayfield
>>>>124 Maximillion Drive
>>>>Madison, Al. 35758-8171
>>>>1-256-837-1051
>>>>
>>>>http://www.hsv.tis.net/~mayfield
>>>>
>>>>DrMayf@AOL.com
>>>>lemay@hiwaay.net <<<<preferred
>>>>
>>>>
>>>>Bonneville Land Speed Racer, '66 Hydroplane Drag Boat (390 FE)
>>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>L.E. Mayfield
>>124 Maximillion Drive
>>Madison, Al. 35758-8171
>>1-256-837-1051
>>
>>http://www.hsv.tis.net/~mayfield
>>
>>DrMayf@AOL.com
>>lemay@hiwaay.net <<<<preferred
>>
>>
>>Bonneville Land Speed Racer, '66 Hydroplane Drag Boat (390 FE)
>
>
>
>
>
L.E. Mayfield
124 Maximillion Drive
Madison, Al. 35758-8171
1-256-837-1051
http://www.hsv.tis.net/~mayfield
DrMayf@AOL.com
lemay@hiwaay.net <<<<preferred
Bonneville Land Speed Racer, '66 Hydroplane Drag Boat (390 FE)
|