m52 with sunbelt sports or s52 cams

[evangreen]

Building an m52 w m50 intake and either s52 or after market cams. Ive heard good things about the sunbelt cams, but also that s52 cams are a nice upgrade for an m52. The sunbelts are 1400 and i can get a used set of s52 cams for around 400.
What will the power difference be on an m52?
Thanks

[SchnellerVert]

Sunbelts tend to be on the higher rpm scale for numbers. Cost 3 times as much and the dyno numbers did not seem to justify the cost on BFc.

[Stu]

Unless you're building a motor to maximize in a race series (such as a D-Mod M52), I'd stick with the M3 cams. You'll probably pickup 10-15whp with the Schricks or Sunbelts, but that's not useable power for a street driven car. The motor will definately be stronger with the Sunbelts as long as they're timed properly and have the right AFR's...but you'll probably find the M3 cams to be better suited from a cost/benefit standpoint.

Remember that a 2.8 M52 is not much different from a 3.0L M3 engine, it's 84x84 vs. 86x86 for the 3.0L...so 220+whp is not far out of reach with M3 cams.

[amdspitfire]

i got a pair of s52 cams for sale if you want, sunbelt and schrick are not worth the few extra hp

[evangreen]

the sunbelt sports say they increase low end torque as well as top end hp, is this not so?

also if i plan to possibly fi the motor which would be better

[Stu]

the sunbelt sports say they increase low end torque as well as top end hp, is this not so?

also if i plan to possibly fi the motor which would be better

True--Bimmerworld spec'd the Sunbelt cams to make more power down low and more overall area under the curve than the Schricks, plus be able to rev to 7600 on stock M3 valvetrain. They will increase low-end power somewhat, yes. However, I don't think you'll be impressed with the difference in comparison to M3 cams, considering the ~$1000 difference in price. Believe me, there are a lot of other areas on a non-M E30 that need attention with motors like these. I'd spend the $1000 difference on collecting parts for a 5-lug swap or a BBK for the stock 4-lug setup.

People always ask me why I didn't put headers or cams or FI on my 3.0L, and I always tell them that the last thing the car needs is more power--It needs money spent on brakes and setting up the car--also tightening the loose nut behind the wheel!

EDIT: The question on Cams and FI....Carl Hugh told me that they always made more power from their turbo kits using stock M3 camshafts compared to Schricks.

[evangreen]

good advice too all, Im doing the engine now only because I already finished the suspension wheels tires and rear end, I might get a bbk later but Ill have to see how the stock brakes hold up to the power.

How much power are we talking about? I mean there's a reason the s52 guys upgrade isn't there?

Thanks

[evangreen]

oh yeah amdspitfire, are you the guy selling them on cl in los gatos

[Stu]

good advice too all, Im doing the engine now only because I already finished the suspension wheels tires and rear end, I might get a bbk later but Ill have to see how the stock brakes hold up to the power.

How much power are we talking about? I mean there's a reason the s52 guys upgrade isn't there?

Thanks

On the street you'll be fine regarding braking, but if you plan to track it, you WILL need larger brakes.
I use a 3.0L in my 318is which is still relatively lightweight (~2600 w/o me in it)...and I don't have near the braking I need, using: Stock rotors, Hawk Blue/HPS, SS lines, dot5 w/25psi bleed.

[windnsea00]

How much power are we talking about? I mean there's a reason the s52 guys upgrade isn't there?

Thanks

If some of the S52 people are like me then they probably upgrade to get that fun top end that the S50 has and the S52 lacks. I know down the line I may want to upgrade, not solely for power but a more fun rush at the higher revs.

[BeirBrennerE30]

it makes a big difference... i like the cams but i have never drivin my car with out them so i dont really know the difference. The car definately pull though.

and if you are going FI you do NOT want cams that are commonly available for a BMW. FI cams are high lift with minimum overlap and are nothing like schricks or sunbelt whick are mid to high lift with lots of overlap. Basically with the high overlap you dont get proper cylinder filling with both valves open at the same time and a pressurized gas entering the cylinder. Its better to let the pressure fill the cylinder instead of trying to suck it in like in an NA application.[/cliffnotes]

[evangreen]

So if possibly going fi it might be a good idea to stick with the s52 stuff

[SpecM]

So if possibly going fi it might be a good idea to stick with the s52 stuff

-Yup. But just be careful with the power, like Stu said, upgrade susp/brakes/wheels/tires too.

-Example: my '88. I had a properly stroked m20 (2.7i) in a semi-gutted (2700 lbs w/ me, I'm about 170-ish) e30 with an open 4.10. Car was quick as all get-out. Stock suspention and brakes, b-caps, crappy tires. I wrecked that car BAD on dry pavement. Almost died. And it had MAYBE 180-190 hp at the crank. So just be careful/smart. ;)

EDIT: btw Stu's car is STUPID fast. He scared the carp outta me one time...