Thoughts on bolt-ons for Dinan/RMS Stage 2 Supercharger

[m3f_Baby ///M3]

Hello all,



I am hoping to improve the performance and reliability of my supercharger setup, which is as follows:



Dinan/Vortech V2 supercharger

RMS aftercooler

RMS 8-rib setup with 6 crank pulley and 3.45 or 3.43 blower pulley

M50 manifold

42lb injectors

Porsche 803 MAF

Nick G. tune

Dinan exhaust



The car currently has 61k miles and I've just replaced both 02 sensors and catalytic converters with new OEM units. I understand and don't dispute that the most efficient way to make power is to go with turbo. However, I need to stick with my current setup as it is important for me to 1.) Pass the CA smog test the right way, and 2.) Use as many period correct parts as I can to build my car.



Recently, the car put down 362rwhp and 300lbs of torque on a Dynojet dyno at 9-10psi. In the past few years, I've been getting between 355rwhp-365rwhp on the 1st pull in 3rd gear. After that, the car would lose around 15-20rwhp on the 2nd pull and thereafter. Also, the oil tends to get hot even under moderate driving conditions. It's not atypical for me to see 250 degrees on the gauge after driving on the freeway for 20-30 minutes in mildly warm weather.



As most of you know, supercharged S52s don't usually feel like it's supercharged unless you're revving the engine past 4k RPM. That said, I was wondering if anyone of you who's experienced in this area can provide some advice as to how I may improve the mid-range power of the car; and perhaps add a little more top end power as well? I would be happy to see anything that's close to 400rwhp.



From what I've gathered, the easiest way increase power is by replacing the blower pulley with a smaller one and adding a meth injection kit. The problem with this is that I am not sure if this is going to provide the additional low end power that I wanted. Also, I am not sure about whether having a meth injection kit is going to reduce the overall reliability of the car since there is now one more thing that I have to worry about breaking.



I was looking into getting a set of RMS headers but really didn't get much positive feedback on them from others. Many said they are not worth the money and won't provide much power increase.



I was also thinking about getting an oil cooler to remedy the issues associated with the high oil temperature. Does anyone know what type/brand of oil cooler I should get and what's the cost of having one installed?



What are your thoughts? Any comments and opinions would be highly appreciated.



Jon

[m3f_Richardsperry]

I'd ask in the FI section of the "other" forum.


But from your description, are you sure the water pump for the aftercooler is working. That's a lot of heat soak after 1 pull...


There are several guys over there, that have made 500+ rwhp with the RMS configuration.

[m3f_Braymond141]

You will need to go to 12psi to get more but that is the max you want to run with stock compression and ARP studs are required. What V2 trim charger? S or Si? T or Ti will be needed beyond 400whp. 12psi is a lot different than 9-10. It really starts to feel like forced induction.


RMS headers are good, just expect to do fab work on them. Full gains won’t be realized unless you have high flow cats and large diameter pipe the whole way. They are a top end horsepower header though. I ran them but I think done over again I would choose a stepped euro style header with Grp N style mid to muffler. The stepped header provides a happy medium between torque and horsepower.


Before adding even more “shit” (this is my word for constantly needing to add stuff to s/c setups) to your car like a meth system, try to improve upon the cooler you have. GT500 heat exchanger (or similar) that mounts in the bumper and an uprated pump (GT500 guys have suggestions) should help. Your current heatsoak issue is normal.


If you do go meth, I would not tune for it, only use it as charge cooling. Yes, you will get more power tuning for it, but if you run out it can be dangerous for your motor. If you use it as charge cooling only it will not matter if it runs out. Or just tune conservatively.


Oil cooler is a big yes. The S54 housing, lines, and cooler all bolt right up. You will need a new s/c feed fitting and a new vanos oil feed banjo bolt to run on the S52.

[m3f_Baby ///M3]

Yeap. I also posted in FI section of the other forum and got some good feedback from the helpful guys there. :thumbs:



The Bosch water pump is definitely good and circulating properly. That was the first thing I had my mechanic check out.



I was a bit disappointed that the car didn't make more power but it seems like there are also many others putting down 360-380rwhp with similar mods. Perhaps the 500rwhp guys are running a bunch more supporting parts?

I'd ask in the FI section of the "other" forum.



But from your description, are you sure the water pump for the aftercooler is working. That's a lot of heat soak after 1 pull...



There are several guys over there, that have made 500+ rwhp with the RMS configuration.

My car's Dinan/Vortech supercharger was installed by a BMW dealership sometime in the early 2000s. Is there a way to verify which type of V2 trim I have?



You're right. I need to make sure that my current setup is capable of handling the heat soaking issue before I start adding more crap to it. Forgive my ignorance, the heater exchanger is an add-on part that further cools the engine, and does not replace the aftercooler, correct? Can a heat exchanger be used concurrently with a meth kit for charge cooling purpose?



I would love to do the heat exchanger and oil cooler at the same time to see how the car drives before messing with other stuff. It's much better to have the full 365rwhp consistently than 400rwhp on one pull and lose 20-30rwhp on each subsequent pull. I believe neither mod is tune related so I won't have to worry about retuning my software, correct?



Thanks again for your help!



Jon

You will need to go to 12psi to get more but that is the max you want to run with stock compression and ARP studs are required. What V2 trim charger? S or Si? T or Ti will be needed beyond 400whp. 12psi is a lot different than 9-10. It really starts to feel like forced induction.



RMS headers are good, just expect to do fab work on them. Full gains won’t be realized unless you have high flow cats and large diameter pipe the whole way. They are a top end horsepower header though. I ran them but I think done over again I would choose a stepped euro style header with Grp N style mid to muffler. The stepped header provides a happy medium between torque and horsepower.



Before adding even more “shit” (this is my word for constantly needing to add stuff to s/c setups) to your car like a meth system, try to improve upon the cooler you have. GT500 heat exchanger (or similar) that mounts in the bumper and an uprated pump (GT500 guys have suggestions) should help. Your current heatsoak issue is normal.



If you do go meth, I would not tune for it, only use it as charge cooling. Yes, you will get more power tuning for it, but if you run out it can be dangerous for your motor. If you use it as charge cooling only it will not matter if it runs out. Or just tune conservatively.



Oil cooler is a big yes. The S54 housing, lines, and cooler all bolt right up. You will need a new s/c feed fitting and a new vanos oil feed banjo bolt to run on the S52.

[m3f_Braymond141]

The heat exchanger is what cools the liquid to circulate through the aftercooler... a radiator simply put. If you have the style that mounts in place of the front aux fan, I have an RMS extra thick race version to replace it. If you have the bumper mount style then look into the GT500 parts.