All Big Six ENGINE POWER 300 TURBO CHARGED EPISODE

Relates to all big sixes

efloth

Well-known member
Idk about having a cat between the engine and turbo. The hotside piping can see up to about 3x boost pressure (meaning if boost is 10 psi, the exhaust upstream of the turbo might be 30 psi) and temps well into the 1200-1500 F range. Not sure how well a cat would live in those conditions.
Interesting point, I suppose that the additional heat buildup could damage the cat. I am running e85 so that may help but I'll be searching the web for someone that has tried this. If not I may just have to be the first. So strange how the quest for more power is never ending 😁
 

pmuller9

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Interesting point, I suppose that the additional heat buildup could damage the cat. I am running e85 so that may help but I'll be searching the web for someone that has tried this. If not I may just have to be the first. So strange how the quest for more power is never ending 😁
 

efloth

Well-known member
Wow! That's awesome, lots of reading to do. The catalytic converter part is still a wildcard.
 

Frank

Well-known member
Supporter 2021
Idk about having a cat between the engine and turbo. The hotside piping can see up to about 3x boost pressure (meaning if boost is 10 psi, the exhaust upstream of the turbo might be 30 psi) and temps well into the 1200-1500 F range. Not sure how well a cat would live in those conditions.
Also, if you have AIR (air injection pump) the higher exhaust back pressure may (?) back feed hot exhaust toward the pump.
 

Firepower354

Famous Member
Idk about having a cat between the engine and turbo. The hotside piping can see up to about 3x boost pressure (meaning if boost is 10 psi, the exhaust upstream of the turbo might be 30 psi) and temps well into the 1200-1500 F range. Not sure how well a cat would live in those conditions.

That seems more true with diesels, or wildly undersized turbines, looking at the setups Holdener tests.
Oxygen sensor accuracy suffers with higher pressures, though.
A rear-mount turbo shouldn't cause much grief for the cats. Or, V-band the cat and turbo, to swap for inspection time?
 

InlineDave87

Well-known member
Thanks for all of the excellent information. Being in California, I am thinking about ways to quickly switch back to a non-tubo setup for bi-annual inspections. The obvious and easy solution would be to install the Turbo behind the cats and 02 sensor. That sounds like a bad idea but with the displacement of the 300 driving such a small turbo would probably still build boost fast enough to be effective. I think id still be closer to the engine than they were in the PN episode. I'm open to any scrutiny or support on the topic.
Another obvious solution is to move to south texas where no one cares about the emissions and fed regulations and some cars are running down the road only being held together by duct tape… im only half kidding the half being the move to texas part… the rest of that is true… sadly…
 

Firepower354

Famous Member
Six CA counties are exempt. I can see a business in there, some place...
Bi-annual, or biennial?

Thermactor check valve should keep backflow from being an issue.
 

Frank

Well-known member
Supporter 2021
Six CA counties are exempt. I can see a business in there, some place...
Bi-annual, or biennial?

Thermactor check valve should keep backflow from being an issue.
That's right. Forgot the valve. Duh. I've never run AIR, only removed it asap.
 

THE FRENCHTOWN FLYER

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Bi-annual, or biennial?
Biennial.
Once every two years or upon sale of vehicle.
Firepower, Do you happen to know which counties are exempt? [EDIT: I just checked w/ the Gargle Machine: El Dorado, Riverside, Placer, San Diego, San Bernardino, and Sonoma.]
 
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Green ford f150

Well-known member
Supporter 2021
E

So how much boost is safe for a towing/truck application? Would a 54mm compressor inducer increase the useable rpm range on a stock 300?
Depends on where in the rpm range your trying to make boost . These engines are tough but not a replacement for a diesel. My truck gets the load moving just fine but I have 4.10 gears when I need more power it is around about 2000 at high way speed on hills so if the turbocharger was building boost by 1800 to 2000 rpm and able to carry out the power to 4500 I'd be happy. I have done a little modeling on these engines and I don't like the efficiency of a small turbocharger on these engines.
 

Green ford f150

Well-known member
Supporter 2021
Guys worried about baking their cats should see Paul's and firepower354's post about remote mounting the turbocharger. Besides it would be way less hot side fabrication and lessen the need for a aftercooler.
 

Firepower354

Famous Member
Biennial.
Once every two years or upon sale of vehicle.
Firepower, Do you happen to know which counties are exempt? [EDIT: I just checked w/ the Gargle Machine: El Dorado, Riverside, Placer, San Diego, San Bernardino, and Sonoma.]
I was pretty sure he'd mis-typed. Between my dog and Google, I can get an answer for most anything. Dog didn't know that one.
 

efloth

Well-known member
I was pretty sure he'd mis-typed. Between my dog and Google, I can get an answer for most anything. Dog didn't know that one.
Yeah thanks everyone for straightening me out lol. I'm in El Dorado County and still have to smog. Amador I know for sure is exempt.

Decipha pretty much killed the idea as the O2 sensors will not work correctly under pressure. It has to be installed behind the turbo. At that point I should just build a completely different (straight pipe) exhaust system and plan on swapping it biennially. Another hurdle he brought to my attention is the old factory MAP sensors on do not handle boost. They read full vacuum once they get pressurized.

Two options: Convert to MAF or find a Escort Cosworth 2.5 Bar MAP Sensor. I am asking what the hardware and calibration requirements are to make this work. I'll check back here when I have it figured out. If you want to follow along: http://forum.efidynotuning.com/viewtopic.php?f=38&t=345
 

67Straightsix

Well-known member
Yeah thanks everyone for straightening me out lol. I'm in El Dorado County and still have to smog. Amador I know for sure is exempt.

Decipha pretty much killed the idea as the O2 sensors will not work correctly under pressure. It has to be installed behind the turbo. At that point I should just build a completely different (straight pipe) exhaust system and plan on swapping it biennially. Another hurdle he brought to my attention is the old factory MAP sensors on do not handle boost. They read full vacuum once they get pressurized.

Two options: Convert to MAF or find a Escort Cosworth 2.5 Bar MAP Sensor. I am asking what the hardware and calibration requirements are to make this work. I'll check back here when I have it figured out. If you want to follow along: http://forum.efidynotuning.com/viewtopic.php?f=38&t=345
In Eldorado County, it depends on your zip code. I live in the Tahoe basin which only requires smog when transferring vehicle ownership.
 

efloth

Well-known member
In Eldorado County, it depends on your zip code. I live in the Tahoe basin which only requires smog when transferring vehicle ownership.
Man, hope you are doing OK. For those who don't know, The smoke is really off the charts bad in the Tahoe region and the Caldor fire is heading that way.
 

King_Kong

Well-known member
The catalytic converter part is still a wildcard.
Are you talking about longetivity of a cat between the engine & turbo? Maybe Google "STS Rear Mount Turbo" to find guys that can comment on any issues with cats between the engine & turbos. The kits have been around for long enough that you should be able to find long-term feedback.
 

reracer

New member
Thinking about this engine combination for my 73 E200. Question: If I run E85 and a max 10psi boost, is it possible to make a hypereutectic piston survive for daily driving? Really would like to avoid custom pistons, and I've gathered that the forged 390 pistons are not ideal. Thanks
 

King_Kong

Well-known member
Is it feasible to have the cats after the turbo?

Are you asking about the "legal side" of a cat installed behind an aftermarket turbo setup?

If so, the cat is probably not such an issue (as long it is EPA-compliant & installed in stock location). Millions of turbocharged cars have left the factory with a cat behind a turbo.

The issues would be with all the other mods (turbo, EGR, ECU tune, etc). And that goes according to how strict the inspections are where the vehicle is registered. In some states, nobody really cares what is done to a vehicle after it left the factory. But in California (& other states), all the mods need to be C.A.R.B-approved.
 
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pmuller9

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Thinking about this engine combination for my 73 E200. Question: If I run E85 and a max 10psi boost, is it possible to make a hypereutectic piston survive for daily driving? Really would like to avoid custom pistons, and I've gathered that the forged 390 pistons are not ideal. Thanks
The hypereutectic pistons will survive as long as there is no detonation.
That means conservative compression ratio and ignition timing.

When you say engine combination do you mean the same turbocharger, cam profile and compression as the video?
 
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