[guerilla twang]

Originally Posted by Dubbedown

You just have to remember though race car engines are always torn down and rebuilt after each race.




Only thing I could fnid on the Sunbelt motor:

http://www.kssmotorsports.com/sunbelt/about_us.aspx
http://www.kssmotorsports.com/sunbelt/services.aspx

and their 2nd link (www.saidheadperformance.com) is dead.

But with that said, I'm sure James could provide some valuable technical info...

Very true, however I believe there are alot of things we could take from the race engine and use to beef up our N52's without making it a cranky racing engine..

[berserkerx]

Originally Posted by mike-y

There is a traditional style throttle body. I've held mine in my hands, so I know.


Also, the head isn't ported from the factory, it is however machined (not cast), so the ports are already very smooth (no casting seams or rough textures inside). They are also pretty much a straight shot from the manifold to the bowl (which is good). There could be improvements made to the bowl area, and also some chamber work, like deshrouding the valve area, but I haven't gotten a good look at what the chamber looks like. Larger valves would also be an option.


As far as the bimmerworld race car, they say "approximately 300hp" which could mean many things. They are probably estimating crank hp, so that would be about 250whp (or less) depending on how loose you use the word "approximately"

So what is the Valvetronic? I have been told thats why we don't have a throttle body? Valvetronic is why Kelford said they couldn't exactly do our cams but could give us specs to give to Schrick.

I was going to look into porting the head still. Going with larger valves and a bit of porting also. I would like to order a used head and have someone port it and see if the flow increases. Would it be better to port the head around a valve design or design a valve around port?

The race car is a dry sump oil pan. Which could almost in itself give it 300 at the crank with the 3 stage manifold and an exhaust with a tune lol.

[guerilla twang]

I don't see how a dry sump would give us that much of a gain..

[berserkerx]

I was saying if its at the crank. If a 330i gets 255 crank stock. then with exhaust meaning manifold also. Then tune it with a bit of headwork, and you are already at that crank power with a dry sump. I mean we would not be there but we would be close. I saw an increase of 50 awhp on a boosted car going to a dry sump.

[mike-y]

Originally Posted by berserkerx

So what is the Valvetronic? I have been told thats why we don't have a throttle body? Valvetronic is why Kelford said they couldn't exactly do our cams but could give us specs to give to Schrick.

The valvetronic is BMW's variable valve lift system. it basically uses a variable fulcrum point on the rocker arm to change the rocker ratio on the fly, which increases/decreases lift at the valve - even though the cam profile stays the same. It was rumored that the throttle body stayed open and only changes in valve lift controlled how much air was allowed to enter the engine. Someone proved this was not true by video taping their throttle body opening and closing, with throttle input, just like any other car.

I was going to look into porting the head still. Going with larger valves and a bit of porting also. I would like to order a used head and have someone port it and see if the flow increases. Would it be better to port the head around a valve design or design a valve around port?

You need to port the head based on what the flow tests tell you. you don't really design a port around a valve, if you go oversized, you can open up the seat, and increase the throat size of the port, but the overall size and shape of the port is not dictated by the valve size, only the transitional area at the valve seat.

Newer cars have much more advanced cylinder heads that are very efficient, so you can't just go and hog out the port and make power, like you used to be able to do with old cars. You can mess one up if you don't know what you are doing.

A good head porter will have a flow bench, and will need a spare/junk head to work with before he touches yours (unless he's already worked on n52 heads). I used to work at a cylinder head porting shop, and we would cut cylinder heads in half to see how thick the port walls were and how much material could safely be removed. Most of the time, you only need to remove a little bit of material. most of the work is in shaping/blending.

And you can't really tell how good a port job is by looking at it - even if it's super shiny and smooth, that doesn't mean it actually flows better.

[berserkerx]

Originally Posted by mike-y

You need to port the head based on what the flow tests tell you. you don't really design a port around a valve, if you go oversized, you can open up the seat, and increase the throat size of the port, but the overall size and shape of the port is not dictated by the valve size, only the transitional area at the valve seat.

Newer cars have much more advanced cylinder heads that are very efficient, so you can't just go and hog out the port and make power, like you used to be able to do with old cars. You can mess one up if you don't know what you are doing.

A good head porter will have a flow bench, and will need a spare/junk head to work with before he touches yours (unless he's already worked on n52 heads). I used to work at a cylinder head porting shop, and we would cut cylinder heads in half to see how thick the port walls were and how much material could safely be removed. Most of the time, you only need to remove a little bit of material. most of the work is in shaping/blending.

And you can't really tell how good a port job is by looking at it - even if it's super shiny and smooth, that doesn't mean it actually flows better.

Thanks that information really helped out. I am trying to decide if I should do a local shop or ship it off to someone that I know has BMW experience. Lol regardless I believe both places would require a different head.

So which one would you personally recommend? Getting the valves and then making the seat to fit them along with doing the rest of the porting and blending?

Okay and one last question. Since we would have the block off to put in the rods and pistons would you recommend honing? I was talking to an STI owner and he did that when he replaced his rods and pistons. He said he honed and went .001" larger rings. Or is it mostly for cast type cylinders?

[mike-y]

well, you don't necessarily need larger valves. just getting a good valve job will increase flow and yield power. most of the heads we worked on did not get new valves, we would re-profile the stock valves and install them with a new 3 angle or 5 angle valve job. Oversized valves were available, but we mostly only used those in race engines, or cars going forced induction from NA.

if you are putting in new pistons, you might as well get it honed.. I've seen newer cars go without a hone, and just install new rings, but if everything is out of th car, it would be best to hit it with a light hone.

Also, pay attention to the weights of the aftermarket rods and pistons.. you want to stay as light as possible, especially for NA. Also get the entire rotating assembly balanced too (crank, flywheel, clutch plate, rods+pistons matched) while the motor is apart.

though if you are on a budget, you can still get good gains with just the top end, without touching the block.. of course, a lot will depend on the tune.

[berserkerx]

Originally Posted by mike-y

well, you don't necessarily need larger valves. just getting a good valve job will increase flow and yield power. most of the heads we worked on did not get new valves, we would re-profile the stock valves and install them with a new 3 angle or 5 angle valve job. Oversized valves were available, but we mostly only used those in race engines, or cars going forced induction from NA.

if you are putting in new pistons, you might as well get it honed.. I've seen newer cars go without a hone, and just install new rings, but if everything is out of th car, it would be best to hit it with a light hone.

Also, pay attention to the weights of the aftermarket rods and pistons.. you want to stay as light as possible, especially for NA. Also get the entire rotating assembly balanced too (crank, flywheel, clutch plate, rods+pistons matched) while the motor is apart.

though if you are on a budget, you can still get good gains with just the top end, without touching the block.. of course, a lot will depend on the tune.

Thanks again for the information. I might still get some valves from Ferrea. They claim that their valves are light due to a hollow stem. If I can get enough information on it I would most likely get a new crank. So far its more promising to go with Wiseco for pistons and K1 for rods and crank. They are partners so I am sure it would work well.

But if there are enough people on board to do it Cosworth is always an option. But that also would depend since I am sure some would want different compression ratios. Some might even want to stroke it and I think that the batch would be identical.

Now we just need the specs and get them forwarded to the correct parties

[guerilla twang]

Here you go guys! Tech specs for the Bimmerworld 325i GTS car!

http://www.world-challenge.com/files..._325_Ver_3.pdf

[TSM330i]

Try contacting VAC. They have full machine shop capabilities and will do custom work. They have also built some pretty impressive race and street engines.
http://www.vacmotorsports.com/

[AlpineSwift]

Originally Posted by guerilla twang

Here you go guys! Tech specs for the Bimmerworld 325i GTS car!

http://www.world-challenge.com/files..._325_Ver_3.pdf

You are king ape, twang.

[guerilla twang]

Originally Posted by AlpineSwift

You are king ape, twang.

I don't know much of anything about all these engine specs you guys are throwing around, but I hope that link provides some useful info for the community.

[chris328i]

The minimal power gains hardly justify the cost to change internal components.

[guerilla twang]

Originally Posted by chris328i

The minimal power gains hardly justify the cost to change internal components.

I was waiting for someone to spout off something like this.

[AlpineSwift]

Originally Posted by chris328i

The minimal power gains hardly justify the cost to change internal components.

What is it with you guys and the doom and gloom attitude?

I swear you'd think comments like this would have fizzled out by now.

[John_01]

I've been wondering what would be the easiest way to increase the compression ratio in the N52. Maybe that would be a good way to get an instant power increase, providing we use fuel with a high enough octane rating. Any comments?

[micah_675]

Easiest way to increase compression is to replace the pistons. You COULD mil the head but, that could cause way more issues than you should be willing to accept. Mostly because no one I am aware of has done it.

Anyone know if the N52 is an interference motor? I am looking for someone who will produce a header for us (affordably) so we can have a good option in that route. If you guys know of someone who is actually making one please let me know.

@chris, go away, if you dont think its a good idea dont comment or follow the thread. Some people want to do stuff just to be the only one who has done it.

[ar design]

Originally Posted by TrackRat

Let's say you install new pistons, rods, cams, stroker crank and see a 50 HP top end increase. At a cost of $10,000+ this is a poor return on investment.

Take that nonsense elsewhere! LOL.... $200/hp is a bargain.

[chris328i]

It would be far smarter for $10K to install a good turbo system and gain more torque across the board and 150 HP.

[micah_675]

Originally Posted by chris328i

It would be far smarter for $10K to install a good turbo system and gain more torque across the board and 150 HP.

When you make one or find one, be my guest. Again some people want a one of a kind thing regardless of cost.

And can we get an IP check for chris and trackrat, they seem to pop up in rapid succession. Not to mention Chris join date so close to trackrats overload in the oil threads. Not to mention their typical OT replys are EXACTLY the same.

[guerilla twang]

lol!

[Johnny D]

This seems like a semi viable option on the subject. Price for what you get isnt bad, and if their performance numbers are accurate its pretty impressive.

https://racingdynamics.com/eStore/in...405290303.html
https://racingdynamics.com/eStore/in...r-systems.html