How much can a se bottom end handle ????

[Novice1]

mt.net full web address please.
Novice1

[93_Clubman]

mt.net full web address please.
Novice1

Ron,
www.miataturbo.net/

In particular there is a DIY turbo FAQ:
http://www.miataturbo.net/showthread.ph ... bf4&t=4288

[NitroDann]

Mate I spend ages on there. Its not power that breaks ANYTTHING, its torque. And 15psi on any turbo is NOT the same as any other.

Dann

[NitroDann]

Maybe I need to clarify this, torque is how hard the pistons gets pushed down by combustion pressure, power is merely a factor of the torque and the rpm which you can make that torque. Rods in MX5s break by bending, that is, they are broken by too much combustion pressure pushing down on them, ie its the torque NOT the power that they fail from.

Secondly, PSi is a measure of restriction of air NOT air flow. So stop telling people that 15psi is 15psi, it isnt that simple.

Dann

[project.r.racing]

really? i thought torque was a measurement of the force required to turn/rotate an object.

[NitroDann]

Correct, the downward force of the conrod levers on the crankshaft, producing torque.
Apart from helping determine capacity (which helps determine combustion pressure) the bore of an engine determines downward force, since pressure is force over an area the larger area the more force is generated against it (this is piston/bore size).

Apart from helping determine capacity (which helps determine combustion pressure) the stroke of an engine determines the length of the leverage arm the piston and rod has against the crank, think about it, when the piston is halfway down the bore the crank arm where that pistons conrod is pushing is at 90 degrees to the downward force (look up an engine gif if you still dont follow), so there fore the longer the stroke the larger the leverage on the crank, producing more torque.

Now imagine that there are 2 engines that both produce the same amount of torque, but one does it at double the rpm, we can gear it down to the same rpm as the other engine (2:1 reduction drive), now the output torque after the gearing is doubled and both engines output rpm's are the same, hence that engine makes more power. It makes the same torque at twice the rpm, therefore it makes twice the horsepower due to its ability to be geared lower, for a greater output torque, but still at the same rpm.

As for PSI isnt just PSI, psi is a measure of RESTRICTION. If you put a boost guage on a turo outlet thats not connected to an engine, it will still flow huge amounts of air but now your guage will read 0psi, because there is no restriction to airflow. 2 identical turbo engines, but one has cams, it produces more power at the same boost pressure as the stock cams engine. Therefore it can produce the same power with LESS boost. This is because with the cams its head flows better, and the same air MASS can flow through with less restriction, therefore less boost.
Its less boost pressure but its easy to see how it is the same airflow. Therefore ANY 15psi is NOT any 15 PSI.

i hope thats clearer to everyone.

Dann

[devski]

This still isnt right, read my post, it may be that 15psi on the stock turbo is the limit (yeah thats about right), but with water injection it might be 13 psi, a bigger turbo and water injection it might be 10 psi.

Dont just deal in absolutes with someone asking advice about his engine, if he throws a large frame garrett on there and boosts 15 psi with his new upgraded intercooler that is NOT the same as 15psi on a hot day from his stock turbo. Its much more.

Dann

I think you need to do some more research and quit speaking out your arse, either that or you fail to comprehend my post. 15psi+ will bend the stock rods with any turbo, not just the stock one. I also stated the power limit which the rods can handel relatively safely. You need to keep power below 200rwkw and 15psi to not bend the stock rods.

Do yourself a favor and go check mt.net

He could comprehend your post. He is just merely showing you how you are incorrect.
Not hugely incorrect but there is a lot more to the equation then you've said. Thats all he is pointing out.

So when you think about it theres no need to jump down his neck when he is trying to be helpful now is there?

It should also be noted that he has more training than " I READ IT ON THE INTERNET IM A MASTER NOW".

Have a good easter.

[NitroDann]

Sorry this post was sent with unneeded vigour because I incorrectly read the comment above regarding 'internet lernin'. I thought it was aimed at me, but i misread it, my apologies.

Dann

[SE10S]

well i have answered my own question lol 240rwkw and 17.5psi time for a stroker

[bundy_harry]

Correct, the downward force of the conrod levers on the crankshaft, producing torque.
Apart from helping determine capacity (which helps determine combustion pressure) the bore of an engine determines downward force, since pressure is force over an area the larger area the more force is generated against it (this is piston/bore size).

Apart from helping determine capacity (which helps determine combustion pressure) the stroke of an engine determines the length of the leverage arm the piston and rod has against the crank, think about it, when the piston is halfway down the bore the crank arm where that pistons conrod is pushing is at 90 degrees to the downward force (look up an engine gif if you still dont follow), so there fore the longer the stroke the larger the leverage on the crank, producing more torque.

Now imagine that there are 2 engines that both produce the same amount of torque, but one does it at double the rpm, we can gear it down to the same rpm as the other engine (2:1 reduction drive), now the output torque after the gearing is doubled and both engines output rpm's are the same, hence that engine makes more power. It makes the same torque at twice the rpm, therefore it makes twice the horsepower due to its ability to be geared lower, for a greater output torque, but still at the same rpm.

As for PSI isnt just PSI, psi is a measure of RESTRICTION. If you put a boost guage on a turo outlet thats not connected to an engine, it will still flow huge amounts of air but now your guage will read 0psi, because there is no restriction to airflow. 2 identical turbo engines, but one has cams, it produces more power at the same boost pressure as the stock cams engine. Therefore it can produce the same power with LESS boost. This is because with the cams its head flows better, and the same air MASS can flow through with less restriction, therefore less boost.
Its less boost pressure but its easy to see how it is the same airflow. Therefore ANY 15psi is NOT any 15 PSI.

i hope thats clearer to everyone.

Dann

That is by far the best damn explanation for both torque and PSI i have ever read, thankyou very much NitroDann


cheers
harry

[sledgehammer]

Pm sent

[NitroDann]

That is by far the best damn explanation for both torque and PSI i have ever read, thankyou very much NitroDann


cheers
harry

Thankyou Bundy,

Sorry sledgehammer, I didnt get a pm from you if youd intended to send it to me.

Dann