My turbo T dyno...thoughts?

[4timesT]

So how many times are you going to contradict me in every freaking thread I post in?

Did I say that boost wouldn't make a bigger difference than a cam change? NO but I guess only a genius like yourself knows such lofty things.

Didn't you say his turbo was too big? YES and then I showed you the numbers posted by a stock unopened engine with a TE45A. Numbers I might add that are only 2 tenths and 4 MPH slower than your ported head, roller cammed, better turbo, 140K mile stock short block car. Yeah no $hit sherlock, the OP needs to run more boost to see the potential of his turbo...think I said that too.

All of a sudden you're the freaking guru around here cause you ran a good number with a 140K mile stock short block. Listen pal, I was running numbers in 2000 with JUNK parts, that took you how many years to run? Oh and you had to correct me in my thread too.

If you need any more proof then go speak to your engine builder or someone who runs stock eliminator.

 

[bison]

So how many times are you going to contradict me in every freaking thread I post in?

Did I say that boost wouldn't make a bigger difference than a cam change? NO but I guess only a genius like yourself knows such lofty things.

Didn't you say his turbo was too big? YES and then I showed you the numbers posted by a stock unopened engine with a TE45A. Numbers I might add that are only 2 tenths and 4 MPH slower than your ported head, roller cammed, better turbo, 140K mile stock short block car. Yeah no $hit sherlock, the OP needs to run more boost to see the potential of his turbo...think I said that too.

All of a sudden you're the freaking guru around here cause you ran a good number with a 140K mile stock short block. Listen pal, I was running numbers in 2000 with JUNK parts, that took you how many years to run? Oh and you had to correct me in my thread too.

If you need any more proof then go speak to your engine builder or someone who runs stock eliminator.

Post your achievements and what it took to get there then jack ass. At least 95% of your posts are in the political forum. You dont contribute chit here bud. You may be a political posting guru but thats all i can see from here.

 

[John Wilde]

Healthy debate is great, let's not turn this into a bromance.

For what it is worth Brian spends a lot of time on here helping
people with his experience. That does not mean his posts are the last
word, but I think as a community we should be respectful of the time and effort he is giving us.

 

[bison]

Healthy debate is great, let's not turn this into a bromance.

For what it is worth Brian spends a lot of time on here helping
people with his experience. That does not mean his posts are the last
word, but I think as a community we should be respectful of the time and effort he is giving us.

Thanks John. My posts certainly arent the last word. Im hear to learn. I do post what i have done myself on my own cars or to others cars and give the details whether it worked or didnt work. Im sure 4 timesT will be posting up his numbers/combos he ran back in 2000 with junk parts for a comparison. Maybe we will all learn something from him.

 

[GNBRETT]

All of a sudden you're the freaking guru around here...

Oh he has been a guru for many years. Nothing sudden about that.

 

[Jerryl]

I can see two philosophies, which I consider to be fascinating.
The term “Big” and “Small” cam is very subjective as these are relative terms. There are some enthusiasts who think you need to go BIG on the cam, while others subscribe to the opposite philosophy.
I break it down to this in my head . . .

1 – If you have bad flowing heads, so you need to get a bigger cam to fill the cylinder, since you need more time to fill and empty the cylinder. With a bigger cam, you can run higher RPM, but, if the port becomes the restriction, the cam will hurt the combo. You can still run high boost, but may never make it into the efficiency range for the cam. Ultimately, VE suffers, and area under the power curve is reduced.

2 - You have bad flowing heads so you need a smaller cam, since the heads only flow until the cylinder is full which does not take long under boost. With the smaller cam, the head will not be the restriction and you can run higher boost to make up the performance difference. Now, since you can get the engine in the sweet spot of the cam, VE is maximized for the combo and area under the power curve is increased.

If one studies the cam timing vs crank angle vs PR, the calcs clearly indicate that on a boosted application, the smaller cam (to a point) is superior because of the biggest enemy in the mechanical design in our application; Exhaust Back pressure, which limits effective rpm range

I can see the argument for both points of view . . . . . . . than there the real world.
Personally, I subscribe to the relative smaller cams philosophy (As Bison described), but take my response FWIW.

 

[bison]

I can see two philosophies, which I consider to be fascinating.
The term “Big” and “Small” cam is very subjective as these are relative terms. There are some enthusiasts who think you need to go BIG on the cam, while others subscribe to the opposite philosophy.
I break it down to this in my head . . .

1 – If you have bad flowing heads, so you need to get a bigger cam to fill the cylinder, since you need more time to fill and empty the cylinder. With a bigger cam, you can run higher RPM, but, if the port becomes the restriction, the cam will hurt the combo. You can still run high boost, but may never make it into the efficiency range for the cam. Ultimately, VE suffers, and area under the power curve is reduced.

2 - You have bad flowing heads so you need a smaller cam, since the heads only flow until the cylinder is full which does not take long under boost. With the smaller cam, the head will not be the restriction and you can run higher boost to make up the performance difference. Now, since you can get the engine in the sweet spot of the cam, VE is maximized for the combo and area under the power curve is increased.

If one studies the cam timing vs crank angle vs PR, the calcs clearly indicate that on a boosted application, the smaller cam (to a point) is superior because of the biggest enemy in the mechanical design in our application; Exhaust Back pressure, which limits effective rpm range

I can see the argument for both points of view . . . . . . . than there the real world.
Personally, I subscribe to the relative smaller cams philosophy (As Bison described), but take my response FWIW.

Good points. In class racing where closing the exhaust valve sooner is so important because of the extreme backpressures. This limits the amount of overlap and increases the speed of the cam profile making it hard to even get enough spring on the head for a hard running engine with iron heads. Problem with stock bottom ends is you really need to get it done under 6000 rpm. From my experience you are better off turning the boost up and extending the usable rpm that way vs more duration since you cant spread the lobes enough and wind up with a too aggressive profile for the small springs. The cars all seem to 330' better with smaller cam profiles. The stock bottom end will take 6000 rpm for a while. Wish i got some passes in with tall slicks at the 33psi i was running the car at for a few months before the #1 piston failed. That would have been interesting.

 

[4timesT]

Post your achievements and what it took to get there then jack ass. At least 95% of your posts are in the political forum. You dont contribute chit here bud. You may be a political posting guru but thats all i can see from here.

Can't use the search function? You posted in my thread, maybe that will help you out...Jack ass.

I did contribute in this thread and of course you jumped all over me, although everything I posted was on point. So STFU mr helper.

 

[John Wilde]

Let's clean it up please.

 

[GNBRETT]

.

 

[John Wilde]

This thread is under moderation, let's not comment unless you are helping the Thread Starter please.

 

[bison]

Can't use the search function? You posted in my thread, maybe that will help you out...Jack ass.

I did contribute in this thread and of course you jumped all over me, although everything I posted was on point. So STFU mr helper.

Yeah, big boy from behind the monitor. I used the search function and went back about 5 pages to see a bunch of posts in the political forum.

 

[John Wilde]

Thinking about locking this thread...

 

[4timesT]

I can see two philosophies, which I consider to be fascinating.
The term “Big” and “Small” cam is very subjective as these are relative terms. There are some enthusiasts who think you need to go BIG on the cam, while others subscribe to the opposite philosophy.
I break it down to this in my head . . .

1 – If you have bad flowing heads, so you need to get a bigger cam to fill the cylinder, since you need more time to fill and empty the cylinder. With a bigger cam, you can run higher RPM, but, if the port becomes the restriction, the cam will hurt the combo. You can still run high boost, but may never make it into the efficiency range for the cam. Ultimately, VE suffers, and area under the power curve is reduced.

2 - You have bad flowing heads so you need a smaller cam, since the heads only flow until the cylinder is full which does not take long under boost. With the smaller cam, the head will not be the restriction and you can run higher boost to make up the performance difference. Now, since you can get the engine in the sweet spot of the cam, VE is maximized for the combo and area under the power curve is increased.

If one studies the cam timing vs crank angle vs PR, the calcs clearly indicate that on a boosted application, the smaller cam (to a point) is superior because of the biggest enemy in the mechanical design in our application; Exhaust Back pressure, which limits effective rpm range

I can see the argument for both points of view . . . . . . . than there the real world.
Personally, I subscribe to the relative smaller cams philosophy (As Bison described), but take my response FWIW.

All fair and good but there's more to this than that. So when does the cylinder actually fill? You say that when that happens the heads stop flowing. So when exactlly is that?

The cylinder gets "full" when the intake valve closes.

In our application we are overfilling the cylinder. Boost is the reason for this but there's a limit to increasing boost and you've reached it when you lift the head.

If you have a good sealing long block and it can take 30 psi on a regular basis and don't want to start changing head gaskets by raising boost to a higher level....then you put in a bigger cam to see more gains. Of course this will also require a higher stall speed but I don't understand why Bison is making a big deal out of this since going to a larger turbo requires this as well.



Mr Bison here likes to jump on one thing while ignoring everything else in my post. A post that was directed at the specific combo in this thread.

Higher Boost DOES NOT increase the useable RPM range or RPM where peak TQ occurs. Quite the opposite. Increasing boost cause max VE to happen sooner....thus LOWERING the RPM where peak TQ occurs...which in turn lowers the usable RPM range.

Maybe he's confused about this because at the same time he recommends to lower the rear gear ratio or run a taller tire?

 

[4timesT]

Yeah, big boy from behind the monitor. I used the search function and went back about 5 pages to see a bunch of posts in the political forum.

Next time look further.

 

[bison]

Higher Boost DOES NOT increase the useable RPM range or RPM where peak TQ occurs. Quite the opposite. Increasing boost cause max VE to happen sooner....thus LOWERING the RPM where peak TQ occurs...which in turn lowers the usable RPM range.

Maybe he's confused about this because at the same time he recommends to lower the rear gear ratio or run a taller tire?

It doesnt? The data logs dont lie. Peak v/e occurs at peak injector duty cycle in my logs and every other log where the dc is highest and the actual a/f is the same at a given rpm. More boost = more torque and a higher flash stall which raises the usable rpm range up and raises the rpm at which peak torque occur unless your converter was way off and prevented the engine from even getting into the power band. It may be a narrower range but its still at higher rpm. Typically in almost all the 3 bolt applications the compressor is never maxed out because the backpressure is so high the turbo will not make more boost unless extreme pressure is used to keep the wastegate from opening. Removing gear loads the engine harder and will give a properly selected torque converter a chance to keep the engine in its most efficient range longer while raising the mph where the converter will couple giving the engine more room up top to clear the traps before it falls on its face if its running a hyd cam setup like most on here.

 

[4timesT]

It doesnt? The data logs dont lie. Peak v/e occurs at peak injector duty cycle in my logs and every other log where the dc is highest and the actual a/f is the same at a given rpm. More boost = more torque and a higher flash stall which raises the usable rpm range up and raises the rpm at which peak torque occur unless your converter was way off and prevented the engine from even getting into the power band. It may be a narrower range but its still at higher rpm. Typically in almost all the 3 bolt applications the compressor is never maxed out because the backpressure is so high the turbo will not make more boost unless extreme pressure is used to keep the wastegate from opening. Removing gear loads the engine harder and will give a properly selected torque converter a chance to keep the engine in its most efficient range longer while raising the mph where the converter will couple giving the engine more room up top to clear the traps before it falls on its face if its running a hyd cam setup like most on here.

I think you meant...peak injector duty cycle occurs at peak VE.

More TQ does raise the the flash stall, no doubt, but the reason why the peak TQ RPM went up is because the converter was too tight to begin with...thus the converter was off from the get go.

If you raise the MPH where the converter couples then you're defeating the purpose.

More gear is good...if you have the cam to take advantage of it.