so, I finally have a spare block and will be building it out for boost. nothing to fancy M52 block bored to 87mm with a S52 crank with rods and 8.5 pistons. I am debating two power options:
option A: Eaton H122 off of a 2008 GT500 (at around 8k miles, helped a buddy do a blower swap and now is now using it as a paper weight, he said he would give me a killer deal on it)
option B: tried and true turbo. good and tight manifold with a hx35/40
I am budgeting for a MS3 PNP, so i will be self tuning this. (first time there as well.... joy.)
as far as i can figure the H122 with stock pulley should be around 575 crank horsepower (napkin math, i would be happy with 400. if you all want i will explain the math i used to get 575)
so! opinions! I know this forum is very pro turbo and anti centrifugal super charger. not sure how it feels about the larger positive displacement chargers.
I would go turbo because it's easier and does not drag on the crank, but I would enjoy reading about someone adapting a domestic takeoff positive displacement supercharger to one of these cars. A couple of people may be using upgraded twinscrew, like Tanks95. And one of our members was involved in the original AA twinscrew kit, maybe stimpee but I cannot recall for sure if it was him -- some searching would tell. Those guys might have ideas for you. Also Mr M52 has been involved in fitting pd systems and may have ideas or even a bracket.
Very Pro Turbo indeed we are, reason being is we try to save people the hassle of it all. Most guys here came from superchargers (not I) and know exactly what most people will go through. I took this same advice and hope I won't regret it. Just keep in mind you won't ever see that torque which is what you feel from a belt driven charger (on an inline 6)
1997 328is - Megasquirt PNP, Holset HX35, Deka 80lb injectors, SPA T3, Precision PW39 WG, Synapse Synchronic BOV, DKM Organic Twin Disc Clutch, Innovate LC-2 W/B, Mishimoto Intercooler, Mishimoto Catch Can, Mishimoto Rad, Devils Own Meth, Porsche 911 calipers with E46 M3 rotors, Corsa Exhaust
I have been talking to MisterM52 about this off an on, and he is all for it. it looks like it would be fairly simple, gut the smog stuff under the intake, use a M112 longer snout, flip the alternator to where the AC was. make a bracket off the motor mount and some of the mount points on the block. pipe the intake up into the factory air boc location. intercooling, gets a bit tricky with the piping but I think it is possible.
The main reason I am even thinking of a PD charger is the price, and that low end torque that would make the car fly. factory the blowers put out ~430 tq at the wheels, granted that was on a 5.4 V8, not a 3.2 I6
If I head down the blower route, I have some ideas that will up the feeling of that kick. just not sure which route I want to go.
Attachment 590951
Years ago, AA posted this dyno of its twinscrew kit versus its rotrex kit. It stopped selling the twinscrew in part because it did not offer enough low end gains to be worth the extra cost.
You can probably find a dyno of a higher power system in the Tanks95 thread. Maybe it is worth it, maybe not. With a responsive turbo, you can do pretty well in the torque department. CES has posted a dyno of an EFR8374 on a twinscroll Steedspeed manifold on an S52 making almost 300 lbs rwtq at 2500 rpm and over 400 lbs at 3000 rpm, which is pretty good response.
Attachment 590952
good info, thanks pbonsalb. how big was the AA twin screw and what was the pulley ratio on it?
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Ohh, also, is one form of boost easier to tune then the other?
AA used a twinscrew and I can't recall whether it was 1.6L or 1.7L. I don't know how fast they spun it, but supposedly it was maxed out around 400 rwhp on an S52.
I am not a tuner, but think a turbo and positive displacement blowers both require a lot more tuning effort than a centrifugal. I don't know that one of the two -- turbo and pd -- woukd be much easier to tune than the other.
after a bit of research the AA kit looked to be a 1.7L unit with a 88mm pulley. That gives it a pulley ratio of 1.65, that means it pumped out 2.8L of air per RPM, and a 3.2L uses 1.6L. that would put it at around 11 psi of boost. I am assuming 100% efficiency, even though that is blatantly wrong as it makes the math easier. using that same math the H122 i was thinking of using has the stock pulley which would be a ratio of 1.9, on a 2L so it would make 3.8L of air per RPM, which is enough for around 20 PSI.
I know the efficiency will drastically change the real world application of this, but since there appears to be no real world numbers for what i am thinking this is what i have. If anybody has any thoughts/experience that could give me a more realistic result i would appreciate the input.
Check with Tanks95. I think he runs a 2.2L twinscrew but am not certain. He has a thread.
1989 E30 - M50B28 Turbo - ZF 8 Speed
holy crap, that calculator is epic, thanks nutzy!
Last edited by chikinhed; 01-19-2017 at 03:51 AM.
'97 M3, Estoril blue, 2 dr, euro 6-spd, EFR 9180 divided T4 .92 IWG, RK tuning, CP 8.5:1 pistons, Eagle rods, Schrick cams, L19 11 mm ARP studs, O-ringed block, Supertech stainless/inconel valves, Supertech springs & Ti retainers, ported head, S54 oil pump/pan, 80 lb. injectors, OBD1 intake manifold, Steedspeed twin scroll T4, 3.5" SS exhaust, eBoost2 EBC, HFS-4 W/M injection, AEM Failsafe, Zeitronix data logger, Racelogic TC, OpenOBC w. ethanol %, Ireland Eng. engine mounts, UUC black tranny mounts w. enforcers, UUC twin disc feramic, ARC-8's, MCS 2-ways, Z3 rack, Rallyroad strut bar, X brace, Eibach sway bars, Ground Control LCAB bushings, Bimmerworld RTAB's, Powerflex subframe bushings, 210 4-clutch LSD, Stoptech BBK, titainium shims, steel braided lines, brake cooling ducts.
What happened at 5500? Melted the tyres?
1989 E30 - M50B28 Turbo - ZF 8 Speed
'97 M3, Estoril blue, 2 dr, euro 6-spd, EFR 9180 divided T4 .92 IWG, RK tuning, CP 8.5:1 pistons, Eagle rods, Schrick cams, L19 11 mm ARP studs, O-ringed block, Supertech stainless/inconel valves, Supertech springs & Ti retainers, ported head, S54 oil pump/pan, 80 lb. injectors, OBD1 intake manifold, Steedspeed twin scroll T4, 3.5" SS exhaust, eBoost2 EBC, HFS-4 W/M injection, AEM Failsafe, Zeitronix data logger, Racelogic TC, OpenOBC w. ethanol %, Ireland Eng. engine mounts, UUC black tranny mounts w. enforcers, UUC twin disc feramic, ARC-8's, MCS 2-ways, Z3 rack, Rallyroad strut bar, X brace, Eibach sway bars, Ground Control LCAB bushings, Bimmerworld RTAB's, Powerflex subframe bushings, 210 4-clutch LSD, Stoptech BBK, titainium shims, steel braided lines, brake cooling ducts.
You can spend $4000 on NA mods, a used supercharger kit or on a used turbo kit. We keep telling them to go straight to the 600+ whp turbo route. Many of us have done all three and are giving solid advice to go straight to the turbo.
I always get a kick out of it when people say "I like the linear power of NA" or "Turbos have lag and no power down low" and then you look at the dyno chart like the one I posted and wonder what they were thinking. With a turbo you can have your power at anywhere you want it under the curve by using your right foot or a boost controller.
Last edited by chikinhed; 01-19-2017 at 08:04 PM.
'97 M3, Estoril blue, 2 dr, euro 6-spd, EFR 9180 divided T4 .92 IWG, RK tuning, CP 8.5:1 pistons, Eagle rods, Schrick cams, L19 11 mm ARP studs, O-ringed block, Supertech stainless/inconel valves, Supertech springs & Ti retainers, ported head, S54 oil pump/pan, 80 lb. injectors, OBD1 intake manifold, Steedspeed twin scroll T4, 3.5" SS exhaust, eBoost2 EBC, HFS-4 W/M injection, AEM Failsafe, Zeitronix data logger, Racelogic TC, OpenOBC w. ethanol %, Ireland Eng. engine mounts, UUC black tranny mounts w. enforcers, UUC twin disc feramic, ARC-8's, MCS 2-ways, Z3 rack, Rallyroad strut bar, X brace, Eibach sway bars, Ground Control LCAB bushings, Bimmerworld RTAB's, Powerflex subframe bushings, 210 4-clutch LSD, Stoptech BBK, titainium shims, steel braided lines, brake cooling ducts.
1996 332IS
Built 3.2
CES/Steed TS Precision 6466, spraying a "$π!℅" load of meth.
Technique Tuning 80# tune.
1/4 mile 10.84 @ 136.72
Your 1 and only stop for all your BMW performance needs
WWW.CESMOTORSPORT.COM
I agree that the Centri style SC kits vs a turbo are a bad choice. If it was centri vs Turbo no question, I would be going turbo.
The real debate for me is this, Turbo is tried and true and a very well researched and documented on this board, but is usually 4-5k. The PD setup though would be a bit more unique, but not as well planned out requiring more effort on my end to make it work, projected price is about 2k with 500 of that set aside for figuring out parts/alternate things I need to do
To some people time is free, to others it's not. There is a clever local guy, with buddies that helped him with CNC work, that has installed a PD SC on his engine. It works but I don't think the power output is anywhere near what it would be if he would have spent the same time installing a turbo set up. If someone said it will cost you $500-$750 above what you will spend for the PD set up and you can have double the horsepower would you do it? Buy a used Spa manifold and a used turbo and that's probably where you'll be at.
'97 M3, Estoril blue, 2 dr, euro 6-spd, EFR 9180 divided T4 .92 IWG, RK tuning, CP 8.5:1 pistons, Eagle rods, Schrick cams, L19 11 mm ARP studs, O-ringed block, Supertech stainless/inconel valves, Supertech springs & Ti retainers, ported head, S54 oil pump/pan, 80 lb. injectors, OBD1 intake manifold, Steedspeed twin scroll T4, 3.5" SS exhaust, eBoost2 EBC, HFS-4 W/M injection, AEM Failsafe, Zeitronix data logger, Racelogic TC, OpenOBC w. ethanol %, Ireland Eng. engine mounts, UUC black tranny mounts w. enforcers, UUC twin disc feramic, ARC-8's, MCS 2-ways, Z3 rack, Rallyroad strut bar, X brace, Eibach sway bars, Ground Control LCAB bushings, Bimmerworld RTAB's, Powerflex subframe bushings, 210 4-clutch LSD, Stoptech BBK, titainium shims, steel braided lines, brake cooling ducts.
I was just going to say that I think once you price things out you'll find that much of the stuff needed for a turbo setup will be needed for a supercharger. Injectors, maf, tune, exhaust, bypass valve, piping, intercooler, fuel pump, wideband, clutch, etc... So the only real difference is the cost of the turbo and manifold vs SC and the brackets and pullies. I think you'll find you will need an 8 or 10 rib pulley setup to drive that effectively and will need to build all the brackets and mess with relocating the alternator and a bunch of tedious BS. I think a used spa and an hx35 or s300 sounds like a lot better budget setup to me.
Yup, I agree with those points as well, and am leaning towards the turbo build. I also just thought about the pressure ratio, I think the Eaton would make insane amounts of heat as I would be running it against 4 times the pressure it did factory. factory boost was 8 PSI, so running it at 34 psi is probably not going to be efficient in the slightest.
It will be a flame thrower at 32 psi and the leakage past the rotors will be appalling
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And would need a 10 rib pulley
that kind of settles it on the turbo, not sure how much a set of custom 10 rib pulleys would be, but that inefficiency would probably bring it down below the centri levels of power.
Thanks for all your help, look for a build thread soonish.
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