Turbo 300 in a F150
- Thread starter Turbo_B
- Start date
The cam is advertised to be good to 5000rpm. Seat of the pants says it runs real strong from 1800 to 4200, at 4500 it is running out of steam. I hardly ever spin it to 5k.
I have the boost control bring in 2 more pounds at 3800rpm to keep the power up, if I were looking for more rpm with this setup it would probably need a few more pounds at 4400.
I have the boost control bring in 2 more pounds at 3800rpm to keep the power up, if I were looking for more rpm with this setup it would probably need a few more pounds at 4400.
Beemer+ford6lover
Well-known member
Its not really all that uncommon especially for factory turbo cars, the engines are designed to work within a set amount of rpms so the heads flow charateristics are set to best match those operatinf parameters. So when you really need the extra go they would squeze a couple extra psi of boost. But the engines won't survive sustained use at those rpms cause they are designed for that. Just periodic splurges into that extra boost. What he has done is pretty much mimic a factory boost set up if ford had ever made one. To bad they didn't 
FoMoCowboy
New member
Beemer+ford6lover":1mba85dv said:What he has done is pretty much mimic a factory boost set up if ford had ever made one. To bad they didn't
I might be a little confused on what you are saying, but Ford HAS put out turbo'd cars in the past and still are.
Beemer+ford6lover
Well-known member
I meant for the ford 300.
FoMoCowboy
New member
ahhhhh, gotcha. agreed, that would have been SICK if the 300 would have come turbo'd from the factory!!
Beemer+ford6lover":3rezmnr4 said:Its not really all that uncommon especially for factory turbo cars, the engines are designed to work within a set amount of rpms so the heads flow charateristics are set to best match those operatinf parameters. So when you really need the extra go they would squeze a couple extra psi of boost. But the engines won't survive sustained use at those rpms cause they are designed for that. Just periodic splurges into that extra boost. What he has done is pretty much mimic a factory boost set up if ford had ever made one. To bad they didn't
I have never heard of this before. Which auto manufacturers have done this? Do you have any examples you can share? I would say nomally you want the boost pressure to stay constant once it spools. An increase would be viewed as "boost creep" which can be caused by too small of a wastegate.
Beemer+ford6lover
Well-known member
None of the manufactures actually claim its being used, but i have looked at plenty of boost mapps from cars on the dyno, like mitsubishi evo's, subaru sti/wrx's, and even with my rx-7. What it does is it creates that peak horspower number that the heads weren't really designed for, well rx-7 its the ports. Thats why on any turbo vehicle porting of the head and matching of the cams alone(except rx-7 its all porting there) will produce a signifigant number change in the higher rpm band without really raising the boost, I have literally watched an evo with porting and matched cams and no change to the boost raise horsepower by almost 100hp just through those mods and careful tuning Manufacturing is a process of compromise, they take alot of these cars and have them raced and well alot of peopl want that similar experience. Most people just want that sudden explosion when ever they do decide to step on it. Very few will every keep the pedal to the metal and those that do are usually the jackass's you'll see on the side of the road with a blown motor.
Really the only way i could show you is to show a bunch of boost maps for stock vehicle and how they act in the higher rpms. But i don't have any.
edit/ oh yeah and you have to remember that most of these motors are using the most efficent turbo for the operating parameters, which is typically lower rpm use. This means most are slightly undersized so when rpm build up its gonna spin that turbo even faster than it normally does creating a slight boost spike, now the wastegates will even the pressure out but they still can only react so fast. edit/
Really the only way i could show you is to show a bunch of boost maps for stock vehicle and how they act in the higher rpms. But i don't have any.
edit/ oh yeah and you have to remember that most of these motors are using the most efficent turbo for the operating parameters, which is typically lower rpm use. This means most are slightly undersized so when rpm build up its gonna spin that turbo even faster than it normally does creating a slight boost spike, now the wastegates will even the pressure out but they still can only react so fast. edit/
FoMoCowboy
New member
Beemer+ford6lover":2n1y9ubr said:
RX-7's came turbo'd from the factory? with the rotary? I didnt know that, I didnt know that rotary's handled boost well (I *THINK* RX-7's only came with the rotary?) How do they handle nitrous?
Beemer+ford6lover
Well-known member
oh yeah all rx- series (3,4,7,8) came with a rotary now the 87 model was the first in the U.S. to have a turbo option and then the 3rd gen rx-7 in 93 was standard twin turbo. Now in japan the rx-7 was standard with a turbo 2nd and 3rd gen and was an option on the first gen if i'm not mistaken. As for nitrous don't really expect the apex seals to last long.
FoMoCowboy
New member
huh........ I only ever heard of the RX 7 and 8. what kind of pressures do guys run on those turbo'd rotaries?
Beemer+ford6lover
Well-known member
the rx-3 came out mid to late 60's and the rx-4 came out early 70's if i'mnot mistaken, as for pressures. I've seen modded engines pushing 38psi(they won't last long though) dailey drivers pushing (18-20) and making 450-550hp and most facotry setup were 9psi-13psi. As much as i love talking about rotaries i think we need to stop thread jacking.
Truthfully? Holsets are cheap and durable! The guys on the dodge truck forums sell their stock ones for not much money.
For this engine, you would not want a smaller turbo, gasoline or diesel based. I had a smaller turbo, made great power off the line, but also wanted to make boost on the highway and it made a lot of noise because of this.
I will never use this turbo to its potential, it will support a pressure ratio far greater than I need. But, its spool characteristics align with the rpm band that this engine is used in and so I chose to use this turbo.
For this engine, you would not want a smaller turbo, gasoline or diesel based. I had a smaller turbo, made great power off the line, but also wanted to make boost on the highway and it made a lot of noise because of this.
I will never use this turbo to its potential, it will support a pressure ratio far greater than I need. But, its spool characteristics align with the rpm band that this engine is used in and so I chose to use this turbo.
Ok, well i am going to get started soon on fabrication for my turbo system. I will start looking around for a diesel turbo in the local yards and ill look out on ebay. Any suggestions on a turbo, i would like a bearing turbo seeing as they spool up at lower rpm ranges and still keep spooling at higher ranges. Looking to start the spool at about 1200 to 1500 rpm and to cap it at 10- 14psi when i am all done with the total build. When i do it at first i want to cap it at 8 to 9psi but every 500 or so rpm i want to up the boost 1 psi to 2psi from the initial start at 1200-1500 rpm. I would prefer to use a cummins turbo or ford turbo from a 6.0L and maybe a 7.5L but i heard the 6.0L came standard with the bearing turbo.
country fried 6
Well-known member
Turbo_B":2pkw04qj said:
is there any disadvantage to the turbo being in boost while cruising, other than the noise?
