Been Thinking About It...

crash-harris

crash-harris

Famous Member
And I'm about to do it too. Thinking about putting a turbo on my EFI 300 when I finally get to start building it up. I'm planning on punching it .030" over to clean it up, new nearly everything, cheb rockers, guideplates, metal timing gears, Comp Cam 252, advance the cam 4*, Keith Black forged pistons, about 9:1 CR, mild porting, and if I turbo, a MS to replace the ECC-IV and I may have to grab some 19 lbs./hr. injectors. I haven't looked into turbos too much but have always wanted to turbo a six. The wall of iron will get dropped in the '90 F150 to take the place of the tired and abused stock 300. I've heard that turbos from 6.5L Duramax diesels are a good match to low end on a 300. The truck is a DD and I'm building it for the trail, mud, and maybe some rocks if I ever find some the right size around here. She works a lot though, clearing trails, pulling trees, etc. Would you guys mind posting/linking some pics of your turbo 300 setup and some info? Since it will be on a DD should I keep the boost under 10 psi or so?
 
For a very wide variety of reasons, you need to keep the boost under 10 PSI, probably in the range of 6-7. The head gaskets available simply aren't up to the task of 10 PSI on a daily driver.

You need to rethink the valvetrain. The Ch**y rockers are a substitute for a camshaft swap, they are not necessarily a good idea with an aftermarket camshaft. Buy the camshaft you want and use it with the rockers for which it was designed. Having said that, is that cam turbo-compatible? You really need to check with CompCams on this. Look at the specs for turbo cams from Isky and possibly Crower and see just how dissimilar they are from the CompCam you're looking at using.
 
You know, I don't recall if the cam is ok for turbos, I'll have to look that up. As for the valvetrain, I do believe that you helped me discuss that in an earlier thread (and I found the valve springs that I would need for the total .4706" of lift). I was thinking more about running 7 or less pounds of boost like Dakota (Superbeast) did with his build. Planning on getting hardened pushrods too whether I go with the turbo or not for the added security. I might look around a little bit more and see if I can't find a cam that will give me around the same amount of lift and keep the bottom end of the rpm range near 800 or less rpm's. I have talked to Comp Cams about my plans as well (before the turbo). I like where the 252 opens/closes versus the 268. The guy said that it wouldn't shift the rpm range around much (he's the one that helped me findout what springs I would need). I'll have to contact them again and see if the cams I'm looking at are a go for turbos and do a little other brand shopping.

EDIT: Also wondering about the usefulness of a turbo from a Cummins 4BT, I may have access to one for fairly cheap.
 
....ok....so let me ask this then, would a T3 or T4 be a good choice?

And is there really any point in running a intercooler on a rig that when the turbo is working the most it will be going less than 20 mph? (Although it would see airflow while driving on the highway).
 
Use a TO4 style of turbo.
Use a cam with no valve overlap.

And an intercooler will always help. Any airflow through it will reduce the intake air temp.

Will
 
Cool, thank you guys. If I have any more q's about my plans they'll be here :lol:

EDIT: Would it really matter what style of T04? What's the difference? Looking at a T04E.

EDIT (again): Would there be any way that I could use a HD exhaust manifold for my turbo EFI setup?
 
J-pipe, my man. The HD exhaust is perfect for this.

I'd maybe look into Holset turbos if you're going the junkyard/ebay route. A HX35 or HX40 would work pretty nicely for a 300. They came on tons of Dodge trucks, and are cheap and good quality. The HX40 is comparable to a T04E...both would be good choices for low-RPM boost in a 300.

The HX40 is a bit bigger, but an HX35 supports over 400 horsepower on a 302. That should be plenty of flow for a very stout 300.
 
YOu can figure out what you need by calculating it yourself. When you start to understand how they work, they get even more fun! Go here:
http://www.gnttype.org/techarea/turbo/turboflow.html

EDIT: I mean here: http://www.gnttype.org/techarea/turbo/turbopage.html

It has alot of good info. For the TO4B there are 3 different exhaust trims in multiple housing sizes as well as over a dozen (IIRC) Compressor trims with multiple compressor housings. There are also alot of compressor maps for them out there. They are also very easy to get parts for (ie flanges and housings and rebuild kits and etc). Im running a TO4B P trim exhaust wheel, V trim intake wheel, .82 A/R turbine, .60 A/R compressor on my project. I aimed for a maximum of 350 horsepower.
 
The T04E's that I'm looking at are using a .50 A/R compressor and a .63 A/R turbine. How would I run the setup with the HD mani? I guess there I'm just really trying to findout what the mounting plate that opens upward on the HD mani is.
 
crash-harris":118vy3r1 said:
...I guess there I'm just really trying to findout what the mounting plate that opens upward on the HD mani is.
Click to expand...

It's the heat stove that bolts to the bottom of the intake manifold and keeps the carb from icing. You need a J-pipe that bolts to the outlet (i.e. bottom) of the exhaust manifold and turns up to mount the turbo.
 
I knew about the J-pipe, but I wasn't sure on the other part, had a feeling that's what it was for though. Thanks. I can just fab a cover to bolt on there and block it off.
 
I used the calculator in the link on the tubro FAQ in this section and got this:

INPUT
Bore: 4.00
Stroke: 3.98
Cylinders: 6
RPM: 4500
Temp: 42* C
Engine V.E.: 70%
Pressure: 8 psi
Compressor Eff.: 60%
I/C Eff.: 70%

RESULT
Engine Capacity: 300
N/A CFM: 352
Temp Before I/C: 92
Temp. Drop: 28
Temp. After I/C: 64
Turbo'd CFM: 487
Air - ppm: 34
Turbo'd B.H.P: 375
Turbo'd Torque: 437

Calculated the percentials on the low end of normal averages since I don't have the turbo or I/C yet and the air temperature outside at about 80*F (summer), 4500 RPM and 8 psi of boost (what I'll run max). I believe that I remember reading that for a turbo build, I need lower compression, near stock compression work or would I be ok with 9:1 or so? And should I be running 19/lbs. injectors since it looks like I'll be making over 300 lbs. of torque at full boost?
 
http://www.turbofast.com.au/turbomap.html

Crash,

I like this turbo calculator. It will map out your compressor flow at different rpm and boost values. You can overlay different compressor maps to see what will work best for your application. Read all the instructions. Keep in mind temperature is in centigrade.

9:1 compression would probably be OK with your low boost. Guys are having great luck with alcohol injection to keep detonation at bay.

It takes about 0.6 lbs of fuel per hp. I think you're short with the 19 lb fuel injectors. Turbo Buick has a good fuel injector calculator and so do some of the injector cleaning people. I don't know their addy though.

If you can have someone weld a flange directly to the manifold, it would be more reliable than the J pipe. That's the way Ak Miller did his 250 and 300 turbo kits. Of course, that depends on if you have room. I'll assume you do being that it's a truck. Someone posted a picture of a 300 with an Ak Miller kit on here. Maybe somebody more computer savy than I can find it for you.
 
68,

That is the person I was thinking about but it's not the picture I remember. I believe there is some more. It definately shows what I was thinking about. One of the ministarters would help with exhaust clearance. Thanks.
 
drag-200stang":yzudvbvs said:
http://www.turbofast.com.au/turbomap.html
If you can have someone weld a flange directly to the manifold, it would be more reliable than the J pipe. That's the way Ak Miller did his 250 and 300 turbo kits. Of course, that depends on if you have room. I'll assume you do being that it's a truck. Someone posted a picture of a 300 with an Ak Miller kit on here. Maybe somebody more computer savy than I can find it for you.
Click to expand...


I was thinking a lot about doing this with the HD mani (if I get one). I should have the room (looks like it) and I can weld pretty well now. If I can't get a HD mani than I'll probably just fab a flange up on 2 short pipes that connect to the EFI mani's.
 
Got another question......I've been wondering about how I would need to set things up to not really allow the turbo to quite kick in until like 1500 rpm's or so. That way Offroad I could get it to spool up when I need it without it opening up big from a stoplight in town...
 
You'll be safe without it. These turbos won't really spool up and make huge power if you don't put a load on the engine. They are load-sensitive by nature. That's the beauty of it; a properly set up turbo engine will act mostly like a N/A car, fuel consumption at cruise and all, until you want it to act up.

Plus, it's hard to size turbos (or superchargers!) to kick in just off-idle without really choking the top end anyhow, and wouldn't make too much sense if you did.
 
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