Another Turbo 300 in an F150

According to Corky Bell, Maximum Boost pg 61, 304 MPH or 0.4 mach is the point at which airflow meets increased resistance (drag) and flow losses are experienced.

Using the calculator http://www.thermalloy.com/product-group/extrusions-na/flowcalc to calculate velocity in MPH
and
http://www.turbofast.com.au/tfcalc.html to estimate air flow in cfm

I modeled an engine with 2.5" IC piping, 6000rpm and 12 psi. This is roughly 670cfm, or 175mph.

Those calculators indicate that you would need to nearly double your airflow in CFM before a 2.5" tube would become a problem!
 
I regapped the plugs down to .030 and it helped getting higher boost before spark blow out now. I put an MSD coil on and didn't make any difference. I plan to gap the plugs down farther...
TurboB did you have any touble with getting your ign timing to work with megasquirt? I realized I havn't been controling timing.
 
MS seems to control the TFI module. Though I am not convinced that it works right- it has been running fine.

I am not too far from convincing myself to have a new balancer turned and sticking an EDIS6 system on the truck.

My MGB runs EDIS4 - I am much happier with that system.
 
Went to the strip yesterday
With street tires and the M5OD. I had horrid traction. I launched in second gear, slipped the clutch down the track quite a ways, and when I finnally let it out all the way it still spun. I would have liked to see what I could have done with better traction. I wasn't the slowest at the track there was an early 90's formula, and a ~98 mustang GT both ran slower than me :)

Edit: On the way home from the track did a 40mph pull with modified Subaru Legacy Gt that had ran a 14.5 previously and pulled away on it.
 
Thanks for keeping this thread going. Your experiences are helping me make some decisions on my turbo'ed 300.

What head gasket are you using? Did you o-ring the block? I ask because I'd rather go composite at about 12psi boost but I can still go copper if I need to.

Best of luck at the strip, by the way.
 
The fuel worked fine. I ended up blowing the headgasket on my stock engine, and root cause may have just been from over heating. The stock cooling system can not keep up with 20psi. If I would have had an electic water pump at the track, I may have been ok. I plan to build engine this winter, but having trouble figuring out what parts to use... Got any pointers?
 
20psi is incredible! How does it drive on 20psi?!

Are you using studs or bolts to hold your head down?

I am limiting boost to around 6.5psi now. Towed a trailer and Volvo to Alabama in October. I found that my water temps would rise to around 200 degrees if pulling a hill around 100kpa. Light boost and I did see temps go as high as 210, this is where my electric fans come on.

I also noticed that oil pressure would begin to drop into the 26-30psi range at 2500rpm if I was in heavy traffic even at 55mph. Once traffic cleared the pressure would return to 34 to 36psi. A thermostatic oil cooler is on the list of improvements!

Ross pistons claimed to make forgings for the 300. From my reading it seems like stock 300 rods are pretty stout if balanced and peened.

I have always put studs in the bottom and top of an engine - if nothing else to make me feel good.
 
I think the head studs are really the key to keeping a head gasket in this engine under boost, that is, with a stock head gasket. I did ARP head and rod studs, but let the mains stock. Since it has a main bearing cap for each each journal, the strength of the crank is much more than a V8 crank, which has a main bearing cap for 2 rod journals.

I feel like there is no way I could pump 20 psi through my engine with the tune that I have. 5 psi is all I want to do on 87 octane, and even with 93 octane I only do 10 psi max.

I have an issue with my stock cooling system, which I think is even smaller than the ones you guys have. In the winter, it is fine, but on a hot day in the summer, I have to watch my temperature.
 
Turbo_B":apd9fa1o said:
20psi is incredible! How does it drive on 20psi?
Click to expand...

It sucks the coefficient of friction between the road and the back tires isn't near high enough. ;)
 
I got my engine pulled apart. The bore measured 4.030 inches with circlular dished pistons likely hypereutectics; they didn't brake with 20psi of boost. I decided not to touch the rotating group just to try an save a little money. New combo with stainless steel valves 1.94 intake and 1.6 exhaust 5 angle valve job pocket port and polish. Roller rockers hyd cam .525 inches of lift, 230 deg intake and 236 deg exhaust @ .050 double springs with 140lbs of seat and 320lbs open pressure. I will do head studs and a Felpro head gasket for now we will see how it holds up. Should be interesting...
 
Question:
Was showing this thread to a friend today who likes boosted modular motors. He got to thinking about the the injector size you're running, said that he thought 42lb injectors would be right at the limit of the injector at 20PSI. I informed him of the heat issues and the increased pressure that the stock 4.9s run with. Mentioned that with the increased heat load from the turbo you'd be getting even more heat soak. As a result, the fuel scaling up would end with something like 55-60lb/hr injectors

I'm not completely sure what you're doing with the fuel, you mentioned that you put a gauge on the system, but never said what PSI you're running.

I feel like I'm sort of half-piecing things together so this might not make sense, but if you toned down the fuel pressure, or if you turned it up but didn't increase the flow rate of the pump, I'm wondering if you're running a little lean which is causing temperatures to rise, which is causing your overheating issues.

I did see that you increased the flow of the pump with the 255 pump, did you still notice overheating after that, or did you get a chance to run it much?



I'm just sort of spitballing here, wondering if something might stick.
 
I hear what you are saying that lean condition can heat things up. I have been pretty careful about having enough fuel. I have an Air/fuel ratio gage in the cab I can monitor the fuel mix. It is driven by just a narrow band O2 sensor, but it still giving an idea of where I am at. I also have a fuel pressure gage in the cab to monitor fuel pressure. I once turned the fuel way up at WOT to max out the injectors, and monitored the fuel pressure, so I could see if fuel pump would keep up. So I am basically injector limited not fuel pump limited. It did overheat after the fuel pump was installed. Prior to the fuel pump I was running 10psi. I don't have electric cooling fans and cooling system is stock.
 
Ok, I got you.
How much pressure are you running on the fuel system? and what are you planning to do to the coolant system to combat the overheating?
 
45psi base fuel pressure; street driving cooling is ok, but if I want to run at the track I'm going to need to do somthing.
 
Electric fans can do so much more than the stock belt driven fan!!! Also look into any possible aluminum radiator options. My 66 Mustang used to overheat all the danged time until I found a CHEAP Aluminum V8 radiator and tossed an electric fan on it. Now I can barely get it to warm up to temp :LOL: I miss my old 300 truck and woulda loved to have seen it with a turbo on it so Im watchin your build! Good Luck!
Matt
 
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