Anyone give me a ball park idea on my boost. 1 5/8 kook long tubes, comp stage 2 cams. Mild port job. I have a stock lower and a 4lb lower and a 3.350, 3.50 and a 4.0 upper I can run. The blower is a 3.4 with crusher. Really wanting to see about 24lbs
3.4 Boost Question
- Thread starter MurderedMach
- Start date
Why? :shrug:
Cranks are snapping off on the larger blower/high boost cars
We have 3.4 crusher with 3.5 blower and the 6.55" underdrive crank pulley stock cams and the bowls cleaned up with 1 5/8 long tubes 3" collectors we see 25psi.
Don't know the HP but went 132mph hitting the limiter at 1000' in a 4200lb race weight Marauder.
I tend to disagree with your assessment.
Is it a good idea to maintain the stock lower cage? Yes it is.
There are many cars with big blower running aftermarket lowers with out issue.
I am also wondering what a 4lb lower snd 3.5 upper would produce on a 3.4 crusher
29 or so on stock heads. Mine made 26 or so with a 3.5
Ok...anyone know what the 4lb lower and 4.0 upper would make?
I gonna guess about 25psi. Going by the 4.0 is 14% larger than the 3.5 so 14% less than 29 is 25 psi.
What are you trying to make?
What are you trying to make?
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Trying to make 20 for pump gas and 25-27 race fuel
Mine spiked my 30psi boost gauge and came down to 29 with a 3.5 upper and a 4lb lower and it made 920 tq hope this helps it has some left in the tune that was on e70 it will get e85 tuned in a few weeks
I love blanket statements about failures.:shrug:
There were a few threads about broken cranks when these cars were still big news.
I broke my crank in two with an aftermarket lower.
Don't talk shit to the guy because you run an aftermarket lower and want to sleep better at night.
Enjoy your motor rebuild. :beer:
I broke my crank in two with an aftermarket lower.
Don't talk shit to the guy because you run an aftermarket lower and want to sleep better at night.
Enjoy your motor rebuild. :beer:
Not talking shit. Just expressing an opinion based upon many year of experience with these cars.
I have slept quite well since I installed the aftermarket lower in 2005.
Actually i am looking forward to a build but 730+ is enough for now.
You might not be able to tell by my SVTperf post count, but I've been around long enough to have seen threads reporting broken cranks and for every broken crank there is some larger number of happy lower pulley users. I even remember a guy with a 3.4 that was cracking blocks due to the blower drive torque cranking down on the stock support center thread, essentially pulling the crank forward. So it could be said that an aftermarket lower would prevent that failure...
The one thing I noticed they all had in common was the stock balancer. Yes I am taking a bit of a leap of faith hoping my IW balancer and Metco ring doesn't break my crank. If it does I won't be going back to a stock lower. I'll be going with a custom billet multi key crank.
The one thing I noticed they all had in common was the stock balancer. Yes I am taking a bit of a leap of faith hoping my IW balancer and Metco ring doesn't break my crank. If it does I won't be going back to a stock lower. I'll be going with a custom billet multi key crank.
Sorry but... :bs:
I did a simple search for "cracked block" in the term section of the mfords forum and found two reports of cracked blocks with big blowers using the factory lower that was showing signs of squishing the rubber grommets. The first thread actually cracked 3 blocks before he figured out the lower pulley was pulling/thrusting the crank.
If you don't want to do the search I described above, go ahead and keep your head in the sand. Personally I like to take in as much data as possible before throwing my hat on an opinion. Which is the whole reason I asked for the data supporting Foofinators opinion. I wasn't being rude. I simply am interested in seeing more data points.
Right now every crank failure I've seen was using a stock balancer. I remember one admitting the metco adapter had come loose and was wobbling which would throw a ton of harmonics through the snout of the crank.
Hell "Joes GT" suffered a crank failure and it wasn't spinning a blower at all! It was spinning a stock balancer though...
If you don't want to do the search I described above, go ahead and keep your head in the sand. Personally I like to take in as much data as possible before throwing my hat on an opinion. Which is the whole reason I asked for the data supporting Foofinators opinion. I wasn't being rude. I simply am interested in seeing more data points.
Right now every crank failure I've seen was using a stock balancer. I remember one admitting the metco adapter had come loose and was wobbling which would throw a ton of harmonics through the snout of the crank.
Hell "Joes GT" suffered a crank failure and it wasn't spinning a blower at all! It was spinning a stock balancer though...
I think there is something to your balancer thought. I have broke a crank not on a mod motor but on my V6 due to a bad stock balancer. The hub on our stock balancers are aluminum and they tend to woller out the keyway then everything goes out of whack.
I never thought about the mod motor balancer causing all these crank failures that I've heard about. Its always been in the back of my mind since we went to the 3.4.
Thanks for bringing it up.
I never thought about the mod motor balancer causing all these crank failures that I've heard about. Its always been in the back of my mind since we went to the 3.4.
Thanks for bringing it up.
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Been running the car with 3.3 upper and 4lb lower making 26.3lbs of boost. Wondering if turning it up to 28lbs would be ok? Anyone know what the sweet spot on the 3.4 are?
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