how much boost can stock eaton handle
- Thread starter Kiddk1
- Start date
More PSI shortens life by alot.
Also, the more boost you run on that little Heaton is going to create less efficient boost, not to mention make it extremely hot.
Also, the more boost you run on that little Heaton is going to create less efficient boost, not to mention make it extremely hot.
I'm no expert on this, but have done some research. With the eaton, it's not about boost, but more about RPM and heat. From everything I've been able to get my hands on, here's the skinny:
Eaton M112 manufacturer specifications show it's max RPM is 15,500RPM. The stock setup on the 03 Cobra spins the blower at 13,579RPM when engine speed is at 6500RPM. We all know that's good for about 8 - 9PSI boost.
The 2.93 pulley spins the blower about 25% faster throughout the entire RPM range, and at 16,916RPM with the same engine speed (6500RPM). This is 9.13% over the RPM max for the blower. This is good for about 11 - 12PSI boost.
The 2.80 pulley spins the blower more than 30% faster throughout the entire RPM range, and at 17,701RPM with the same engine speed (6500RPM). This is 14.2% over the RPM max for the blower. This is good for about 12 - 15PSI boost.
Not enough difference between the 2.8 and 2.76 to post here.
The real question is what are the differences in cylinder heat temps that may be causing some of the failures we're all reading about. IMO, go smaller than a 2.93 and you're chartering dangerous territory.
Our engines were not designed to handle the extra heat.
Mint
Eaton M112 manufacturer specifications show it's max RPM is 15,500RPM. The stock setup on the 03 Cobra spins the blower at 13,579RPM when engine speed is at 6500RPM. We all know that's good for about 8 - 9PSI boost.
The 2.93 pulley spins the blower about 25% faster throughout the entire RPM range, and at 16,916RPM with the same engine speed (6500RPM). This is 9.13% over the RPM max for the blower. This is good for about 11 - 12PSI boost.
The 2.80 pulley spins the blower more than 30% faster throughout the entire RPM range, and at 17,701RPM with the same engine speed (6500RPM). This is 14.2% over the RPM max for the blower. This is good for about 12 - 15PSI boost.
Not enough difference between the 2.8 and 2.76 to post here.
The real question is what are the differences in cylinder heat temps that may be causing some of the failures we're all reading about. IMO, go smaller than a 2.93 and you're chartering dangerous territory.
Our engines were not designed to handle the extra heat.
Mint
These KBs don't stay cool either ... I wish I could see some numbers comparing temp differences.
Anyway, Eaton becomes less efficient the faster you spin it.
You should be able to maintain 13 PSI to red-line ... maybe even 15. past that, you'll be losing boost, creating more heat, but would you ever end up with less boost on the big end if you start higher at the low end?
I know that with my KB running along side other comparable Eaton cobras, I'm neck-n-neck until the RPMs rise above 4K. At 6K, i'm pulling ahead and can continue to pull as long as i don't mess up...
but i guess the answer to your question is yes, both :lol1:
I do know that running too much boost can certainly shorten the life of you engine ...
Depending on what you want to do & how much boost or HP/TQ you are looking for may help us answer your question.
My eaton was at 15 PSI & only dropped a little up to red-line ... to ~13 PSI.
Anyway, Eaton becomes less efficient the faster you spin it.
You should be able to maintain 13 PSI to red-line ... maybe even 15. past that, you'll be losing boost, creating more heat, but would you ever end up with less boost on the big end if you start higher at the low end?
I know that with my KB running along side other comparable Eaton cobras, I'm neck-n-neck until the RPMs rise above 4K. At 6K, i'm pulling ahead and can continue to pull as long as i don't mess up...
but i guess the answer to your question is yes, both :lol1:
I do know that running too much boost can certainly shorten the life of you engine ...
Depending on what you want to do & how much boost or HP/TQ you are looking for may help us answer your question.
My eaton was at 15 PSI & only dropped a little up to red-line ... to ~13 PSI.
Last edited:
MY Eaton hits 17 - 18PSI with a 2.75 and 4lb lower. On the top end it drops to 15...
Stock Eatons.. I do not know how they do it, but they ride out..
So what are the standard gains say with like my car? I have a cat-back and FIPK.
How much would I gain with a
3.4
3.2
2.93
2.8
and how many rpm is the blower spinning with each setup?
What pullye size is hitting the 15,500 at 6500rpm on the motor?
How much would I gain with a
3.4
3.2
2.93
2.8
and how many rpm is the blower spinning with each setup?
What pullye size is hitting the 15,500 at 6500rpm on the motor?
Last edited:
03soniccobra01
Banned
Due to the worry of temp I am looking into devoloping a system that would keep the intake charge below 150 degrees @ 16 lbs of boost. It's almost done and when it is I will post the cost and avalibility date....Keep tuned hear! I am starting a tuner buss. and hope I can help you guys as well as myself.
Dont forget your fuel return system above 500rwhp.It will run cooler and much more efficiently.You can get one off a 99 GT and use some Earls larger diameter.
WE are now or very soon stocking this system,its perfected and good for 1000+ rwhp,a bit to powerful for my street car,but hell fire with my F series Prochsrger on my soon to be 8 second car.
We have to find the correct race category or go bracket with the ATI and C-4 trans and B&M ratcet shifter and 4:56 gears.
The best of luck and good graces of the Lord,Dave Smilovic
WE are now or very soon stocking this system,its perfected and good for 1000+ rwhp,a bit to powerful for my street car,but hell fire with my F series Prochsrger on my soon to be 8 second car.
We have to find the correct race category or go bracket with the ATI and C-4 trans and B&M ratcet shifter and 4:56 gears.
The best of luck and good graces of the Lord,Dave Smilovic
bump
ALA G8R
Banned
pulley.............................rwhp/tq.........max spin
Stock 3.65 (measured)..407/386........13134
3.4 (measured)..............429/397.........14099
3.2 (estimated)..............440/415.........14980
3.1 (measured)..............455/452.........15454
2.93 (measured).............466/472.........16361
2.76 (estimated)............470/485..........17369
If Mint Julep is right with the 15,500RPM Max for the eaton 03 Cobra spins the blower at 13,579RPM then the
3.10 is right under the safest 455/452..15454=46 under the limit
2.93 (measured).............466/472.........16361=861 over max
2.76 (estimated)............470/485..........17369=1.869 over max load!!! Were did you get this info Julep and ALA G8R web site???
I still can't decided what pulley size to go with, I hear of people useing a small 50 or 30 shot just for the cooling factors but is that very safe? So what should I go with..
3.10=Safe
2.93=Just Over
2.80=Plan on buying a new sc????
What to choose....:shrug:
Last edited:
ALA G8R
Banned
Heck, I've got the BilletFlow interchangeable system and ended up with one of each.
The 3.1 yielded good gains, but I like the 2.93 better. I am currently running the 2.93. I've got the 2.76 for when I port the SC. I'll probably use the 3.1 if I go on a long highway trip. All three use the stock belt with my 4-piece BilletFlow idler set.
If I were to choose only one, I would go with the 2.93.
The 3.1 yielded good gains, but I like the 2.93 better. I am currently running the 2.93. I've got the 2.76 for when I port the SC. I'll probably use the 3.1 if I go on a long highway trip. All three use the stock belt with my 4-piece BilletFlow idler set.
If I were to choose only one, I would go with the 2.93.
Last edited:
These are power numbers on an otherwise stock motor? I didn't think '03s put down that much power with a stock pulley.
ALA G8R
Banned
Oops. I had a catted x-pipe, catback, and CAI. All those numbers that say measured are just that, measured on a dyno (SAE).
Users who are viewing this thread
