Other mods that compliment S52 supercharging?

[TX99M3]

I'm sure this info is in the forum but I've been searching for weeks with few clear answers. I am planning to put an AA stage 2 supercharger on my stock 1999 M3 (86K miles). I have owned her for 18 years and need to spice her up. Before the turbo fans chime in, I get it, but this is what works for me based on cost, simplicity, reliability, engine life and general driving characteristics. She has never been a daily driver and I do not plan to race/track her. Just looking for more fun on weekend spins out on the back roads.

I know there all kinds of other performance mods possible. My questions is: what other mods really compliment/add to the AA stage 2 without breaking the bank (and without sacrificing mid-range torque just for a higher top end)

Specifically, what benefits/effects might I expect from:
- m50 manifold swap
- aftermarket headers (and which are best)
- more aggressive cams (and which would be recommended)
- aftermarket cat back exhaust, etc.
- and any other suggestions relevant to my goals

If this is all spelled out clearly somewhere, my pardon and please just point a newbie to it!

[bluptgm3]

Most likely need larger injectors, 3.5” HMF and at least a mild tune.

SuperSprint Euro Headers, SuperSprint ‘cat’ section, SuperSprint Switzerland muffler.

Schrick 264/256 cams can be installed with stock springs.

Zionsville radiator for cooling.
3.38.1 LSD (from M3 automatic) mated with 330ZHP / S54 6-speed.

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[abradic]

At no point will you lose your midrange torque with a blower, you will always have more than stock. The M50 manifold, headers, and Schrick 264/256 cams will not give you any issues of mid range torque, you'll be way better off than stock. bluptgm3 has a nice setup in his suggestion, SuperSprint stuff is awesome. Others swear by RMS headers, that they're the best for supercharged cars, but you'll need to adapt it to your exhaust. I went with AA headers and track pipe going through an Eisenmann Race exhaust...it sounds absolutely amazing. You're probably on the original head gasket, throw in a cut ring head gasket. You'll need an upgraded clutch, I have been happy with my Clutchmaster FX250. You may even need to upgrade your suspension, I noticed way more nose lift on the stock setup. The one thing not on your list you should consider, especially in Texas, is a meth kit. I didn't go with one right off the bat but I should have. IAT's is the name of the game, and meth is a great addition. You don't have to tune for it, or you can do a slightly more aggressive tune for a bit more power.

[pbonsalb]

I agree with the posts above. I supercharged my 99 M3 with a Vortech based stage 2 kit and all supporting mods and enjoyed it. Stock clutch will start slipping around 300 lbs rwtq, which you might get with around 375 rwhp.

M50 manifold, headers, track pipe, water/meth injection, Schrick 264/256 cams, aftermarket tune and hfm and injectors and fuel pump for the mods and power. 42 lb injectors may be insufficient at 400 rwhp and a 255LPH pump is not good for much more. Remember, the supercharger drags a lot on the crank when the motor is putting down 400 at the wheels. The blower may be using up 50+ crank hp to produce that power, so the factor back to crank power should be greater than with a turbo that recycles exhaust gas energy.

Also liked a 3.38 diff. 3.64 was also fun but made me want a 6 speed.

You may need to enhance engine cooling with the blower in a hot climate, unless all you do is the occasional one-off highway pull for 5 or 6 seconds.

[TX99M3]

Thanks for all the input guys! If I have the head off to do the gasket and studs, would it be easier (cheaper?) to get the Schrick cam installed at that time (given I don't have the cam blocking tool BMW recommended)? Also, I have heard of people replacing the head studs without actually pulling the head. If I'm only looking at about 350 rwhp, could the stock gasket hold with ARP studs?

[pbonsalb]

Cam tools are about $40 on Amazon or eBay. Not changing the gasket is up to you. They don’t last forever and yours is over 20 years old. But if you buy the cam tools and change the cams yourself, it is really easy to change to studs then. When I did this, the cams were installed, which made it harder. Also you want to get all the oil out of the holes since liquids don’t compress well. Likely only a problem on the passenger side since oil drips downwards. Mityvac will suck it out and twisted up paper towel will wick it out.

If only 350 rwhp, why spend $1100 on cams plus the trouble of installing them?

[TX99M3]

My bad pbonsalb! 350 rwhp is what I understood could be expected from the AA stage 2 SC, I wasn't calculating in the cam. How much more could I expect adding the Schrick cam? I'm guessing that would make the new head gasket more critical.

Also, I didn't mean the cam block but the BMW cam removal tool. However I also found a really good youtube series showing how to swap out the cam without the cam removal tool. Seems especially easier if the head is removed so that goes hand-in-hand with a new head gasket.

My goal was the SC within the year. However seeing the SC add ons being recommended here, I may just source the parts in the TMS stage 3 performance kit and tune using their software in the next few months, then save a little longer and add the SC and retune with the provided SC tune from AA.

[bluptgm3]

However I also found a really good youtube series showing how to swap out the cam without the cam removal tool. Seems especially easier if the head is removed so that goes hand-in-hand with a new head gasket.

And at this point with the head off, new higher seat pressure valve springs would be a good idea….and easy.


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[pbonsalb]

I have done cams a dozen times and never used a cam removal tool. And I always install the cams with the head installed on the car —even if I had the head off, I install it and then do the cams. There are plenty of DIY showing how to do this.

There are some good aftermarket tuners to consider. The TMS tune probably has not been updated in 10 years.

The problem with just naturally aspirated mods is that the power gains aren’t that great. I’d just go right to the supercharger and skip the other mods rather than divert funds to the other mods and wait on the supercharger. I’d rather skip headers and track pipe and cams and have the supercharger. Maybe add those minor mods later when you have more money.

Cams that add 10 rwhp naturally aspirated might add 20 rwhp with 10-12 psi boost. But $1100 is a lot of money for 10-20 rwhp.

Sometimes used supercharger kits pop up. Just make sure it is complete. If you don’t know what you are doing you can end up with someone else’s headache.

[TX99M3]

SC first was my thinking originally. My main question really was which of the typical NA mods still give good benefit for cost if the car is already supercharged?

I saw a before and after dyno with the Schrick cam and it showed some fair low to mid-range torque gain also. Is that typical?

The m50 manifold swap is fairly affordable. Does it benefit a supercharged car as much or more?

I've seen some people post that the stock s52 headers and exhaust are fairly decent and that upgrades do not net that much, just sound better. Any thoughts on that? I won't be deleting the cat.

Is the tune that comes with the AA stage 2 SC decent?

[abradic]

SC first was my thinking originally. My main question really was which of the typical NA mods still give good benefit for cost if the car is already supercharged?

I saw a before and after dyno with the Schrick cam and it showed some fair low to mid-range torque gain also. Is that typical?

The m50 manifold swap is fairly affordable. Does it benefit a supercharged car as much or more?

I've seen some people post that the stock s52 headers and exhaust are fairly decent and that upgrades do not net that much, just sound better. Any thoughts on that? I won't be deleting the cat.

Is the tune that comes with the AA stage 2 SC decent?

The M50 manifold will probably the best mod you can do for a supercharged S52...or any S52 for that matter. That allows everything else to be maximized. There is absolutely no reason not to do it, or any drawbacks to it. Long tube headers will benefit you greatly, you will definitely see a great benefit to doing the headers and exhaust. On an NA car? You won't see much with just a header or exhaust car, but on a boosted car you will.

You can probably expect a roughly 15 to 20 whp and wtq gain across the power band with cams. The one thing with using them in a supercharged application is that you will have to degree the cams due to valve overlap. We installed them in my car when I supercharged it, and then shipped the car to AA for an in house dyno tune. Karl wound up having to degree them a bit due to valve overlap. I don't know what he set it at.

As for the off the shelf tune...I always think a dyno tune is best to get a better tune, safer, and the most power. However I don't have experience with an off the shelf tune since AA tuned it in house, so maybe others can chime in on that.

If you add cams along with water/meth injection, and associated bolt-ons, you could be knocking on the door of 400 whp. Or you could upgrade the entire kit to the C38-92 blower and really get some power It's a cost, but you have potential for over 500 whp down the road.

[pbonsalb]

So tell AA that you will buy an intercooled supercharger kit but you want a dyno tune. If you can’t go to southern FL, get AA to agree to revisions based on you local dyno results and your data logging through the obd2.

With an upgraded supercharger, intercooler, all the bolt on mods, 93 pump plus water/meth on an S52, I did 463/368 on a Dynojet in SAE at 17 psi on a first draft prototype tune. This was 13 years ago, and tuning has gotten better since. Abradic is in the same range with just 12 psi boost.

But totally stock other than 11-12 psi from an intercooled supercharger with an off the shelf tune on an S52 on 93 pump, you are looking at 375 rwhp, and 350 on 91. 450-475 is max if you do everything with custom tuning. Maybe 500 — I have read of 3 or 4 E36 3.2L (USA) with 500 rwhp from a centrifugal in 15 years.

I know you don’t want to hear about turbos. Turbo will literally run away from the supercharger — I remember running one of those 500 rwhp centrifugals at New England Dragway about 13-14 years ago after I changed to a turbo and it was close to a 10 mph trap speed differential. I had also gone 3.23 to 3.38 to 3.64 diff with the centrifugal to multiply torque better. The car really zinged to 7000 in every gear but I wanted a 6 speed. The turbo makes so much more torque than the centrifugal that I ran a 3.15 and have thought about a 2.93.

[Jamesons Viggen]

Yeah, I've been down this road.

I've got an update to post about my tuning saga, but yeah 500whp@18psi is where I've ended up. I learned some things the hard way during all this. For example, 15-18psi doesn't matter if you are inhaling HOT air with HIGH IATs.

[abradic]

Contacting AA for a remote dyno tune is a great option if shipping your car to them is not an option. There should be a performance shop with a dyno that would be willing to coordinate with AA, and AA may even have someone they work with in some close proximity to you. Bear in mind all of our power levels are with various blowers. I'm on a Rotrex C38-92, pbonsalb and Jamesons Viggen were on a Vortech V2 T-Trim, another great blower that's bigger and flows well. In actuality I wish someone made an intercooled kit for our cars with that blower, but it never happened. I love the Rotrex, but with Vortech you would have had more blower options. I'm guessing your blower is a Rotrex C38-81? If so you're probably going to max out at roughly 11 psi and with every mod 400-ish whp. At least that's what I have seen as the top end on here over the years.

Also, just as a correction to my signature which I edited. I have seen up to 13 psi on my setup. I was told 12 psi was all that was seen on the dyno but they were probably slightly short of redline. It's semantics really, but I'd rather have that more accurate. I have one more pulley option to get to 16-17 psi, as well as tuning for meth, but that requires pistons and rods.

Turbo is no doubt faster. If your goal is ultimate speed, or that punch in the back, pull like crazy torque, that's what you should look into. Not to say you don't have plenty of torque on the SC setup, you have plenty, but it's not close to a turbo setup. The supercharger feels more race like, motorcycle like in that as you rev out it gets better and better. Rather than a big punch and a big pull, it builds up as you go. It's a lot of fun to rev out, especially with our motors because they are so fun to rev out. It's what you want out of the car. You'll have to learn to peddle the throttle the first couple gears no matter which way you go! The best trap speeds you'll see on a supercharged setup is 120-125 mph, and that is with the best blower, meth, and all the mods. Turbos I have seen many in the 130-135 mph range. 60-130 mph times, with a dragy I was in the 9.5's. Turbos I imagine break into the 8's and 7's. With a maxed out C38-81, you'll probably be a 12-12.2 1/4 mile with a 116 mph trap speed.

[pbonsalb]

RMS used to sell its small liquid to air intercooler kit separately for Vortech blowers using RMS or Dinan brackets that space the blower towards the front of the car and use a dedicated blower drive crank pulley. Maybe they still would sell if you contacted them. It is what I used and what one guy used who made just over 500 rwhp on a Dynojet. I think Viggen has a custom air to air unit.

I would love to see a water to air charge cooler manifold like RMS has for the Euro E36 M3 but they never went past the prototype stage for the USA E36. Another great one would be a version of what Dinan did for the E46 M3 with an air to air unit in front of the radiator and very elegant custom piping through the radiator support sheet metal.

Also be fun to see what one of the new Vortech T trim would do—mine was an older impeller design. Still, a blower tripling stock power adds a lot of heat to the motor since it is dragging on the crank.

[Jamesons Viggen]

RMS used to sell its small liquid to air intercooler kit separately for Vortech blowers using RMS or Dinan brackets that space the blower towards the front of the car and use a dedicated blower drive crank pulley. Maybe they still would sell if you contacted them. It is what I used and what one guy used who made just over 500 rwhp on a Dynojet. I think Viggen has a custom air to air unit.

I would love to see a water to air charge cooler manifold like RMS has for the Euro E36 M3 but they never went past the prototype stage for the USA E36. Another great one would be a version of what Dinan did for the E46 M3 with an air to air unit in front of the radiator and very elegant custom piping through the radiator support sheet metal.

Also be fun to see what one of the new Vortech T trim would do—mine was an older impeller design. Still, a blower tripling stock power adds a lot of heat to the motor since it is dragging on the crank.

I have the RMS after cooler and use an Terminator Mustang heat exchanger.

While the car has been with CES for awhile, we found the RMS cooling just can't support my boost levels.

My IATs were through the roof.

The best solution we came up with is installing the Snow Meth kit. IATs dropped over 80 degrees as intended.

[TX99M3]

Thanks for all the great input and suggestions, guys! I appreciate you sharing your expertise and experience!