Here goes nothing.....

[kameleon]

I know it has been a while but I am close to finally starting my turbo 300 project. My goals are to get a reliable 300RWHP+ out of this beast on full boost. On a regular day I can cut back on boost. My idea is to use 2 toyota ct-26 turbo's (I have them laying around). I know that these turbo's can do 15-16psi steady but beyond that they are pretty useless. I do want to run intercoolers for them too. Basically I will have to convert my truck to EFI for this to work properly as I plan to use megasquirt and the ford EDIS setup to help aid in tuning. I still want to be able to haul heavy loads if needed but mainly this is going to be a street truck.

A big thing is this: should I go for the twin setup or sell them and put money with them and get a good single? Also I know that there has been a lot of people trying different things since I went to the darkside (imports) and I know that there is more info out there on turboing these beasts. But what will it take to get me to my goal of 300 RWHP+?

As of right now I have my stock 300 that came in my 1980 f-150. I stand a pretty good chance of it having the forged internals as it was a HD truck for a utility company. I plan to replace it with an EFI engine (used) for while I do the rebuild. I have the efi engine and it was free from my brother. So I figure just add a low pressure electric fuel pump, cap the A.I.R. crap and slap my manifolds on it and call it good.

Now comes the main questions:

Which head would you use (efi or carb)
Oversized valves? (sbc one?)
stock compression pistons (8:1)?
should the stock clutch hold at that power level?
what size injectors should I be looking at?
what manual transmission will hold that power?

The main thing I am worried about is the last one. I had the "indestructible" Borg Warner T-18 wide ratio in the truck and still fried 3rd and 4th. Now I have a 3spd out of a '70 with a 240 I-6 and it just ain't what I want. I really want a 5 speed manual tranny. I know most of the newer ones will bolt up but I will need to convert to a hydraulic clutch setup.

Any input to this boost addicted, broke, and confused person?

 

[Anonymous]

well, as long as your peak goal is 300 rwhp I think the CT26's will be just barely enough.

Use the later model EFI 4.9 manifolds with dual outlets, then weld up some "J" pipes to mount the turbos on.

 

[StrangeRanger]

Which head would you use (efi or carb)
Oversized valves? (sbc one?)
stock compression pistons (8:1)?
should the stock clutch hold at that power level?
what size injectors should I be looking at?
what manual transmission will hold that power

The carby head is more amenable to adding the oversized valves. You would need to open up the EFI head a bit to fit them. At the 300 HP level, you'll want to have them, so I tend to think the carby head is the better way to go. What are the CC volumes? you want the bigger of the two.

Aren't stock pistons 8.8? You want less compression, 8.0 sounds about right.

You're probably going to need slightly more clutch.

300 FWHP is going to require 30# injectors @ 55 PSI, 36# injectors @ 39 PSI. 300 RWHP will probably require more depending on what tranny you use:

30 x 6 x ((55/39)^0.5) x (1/.55) x 0.80 duty cycle = 350 BHP

24 x 6 x ((55/39)^0.5) x (1/.55) x 0.80 duty cycle = 280 BHP

36 x 6 x (1/.55) x 0.80 duty cycle = 315 BHP

If you use a rising rate regulator, you may be able to use the 24# units.
It depends on the regulator.

It's not the power that kills trannies, it's the torque. If oyu're looking at making 300 BHP @ 5000 RPM thats only 315 ft-lbs, almost any tranny will survive the experience. If you're planning on 300 BHP @ 3000 RPM, that's 525 ft-lbs, which will break almost any tranny. What are you planning on doing with the truck? That makes a big difference in tranny selection.

If you use the Ford EDIS system, what are you planning on doing for a crank trigger?

 

[kameleon]

Thanks for the replies guys. I planned on making my own manifolds to mount the turbos to so that is not a big deal. Actually I thought about using a modified ct-26 like I have on my mr2 turbo. It basically takes a to4e (?) compressor wheel and puts it in the stock ct-26 housing. Mine is what they call a 50-trim. It holds boost alot better than the stock ever did.

As for the pressure regulator I planned on using an aeromotive a1000 pump and the matching regulator that does boost compensation. So I should be ok on that.

And for the crank trigger I was going to use the stock ford edis trigger wheel. I was going to weld it to my crank pully and go like that. I know I have to have it balanced but that is no biggie.

The engine I am hopefully going to be able to get the rotating assembly balanced to within 1 gram. That should help some. I don't really care about revving too high to make power but a redline about where I am right now would be acceptable (4500-ish). I guess I just need to start playing with numbers in desktop dyno to see what I need to do huh?