From knowing nothing to having a Thunderbird supercharger on an m20b27i

[Ether-D]

I will do that Taco. But keep in mind guys, that the intercooler is not functioning at all. After I get the intercooler functioning I'll hook a laptop to it so I can data log and observe while driving. If the temps are still high, I'll consider the meth.

BTdubs, those intake temps were after I'd been revving it and whatnot for 15 minutes. It was completely up to operating temp. And non functional intercooler (no liquid in it or pump to pump it).

And my tune starts pulling back timing at 130.

[The Dark Side of Will]

"Sitting there idling" could be heat soak & pulling radiator air too.

Ditto on "get more data"

[Ether-D]

"Sitting there idling" could be heat soak & pulling radiator air too.

Ditto on "get more data"

Definitely heat soak.

[Q5Quint]

Sorry about your rocker- I try to keep my old head below 5500 to attempt and prevent this, and pull more timing more than I should above 5500.

I am trying to find a log of my turbo car idling but cant seem to find one. During some runs it look like my mat temps were at 80-90F and then would spike over 100 after a few pulls. Around 100 or below seemed normal, so if you are hitting 150 heat soaking that is pretty woah, also considering you are not sucking air through a spinny blade attached to your hot exhaust.

Ambient here doesn't get over 80F usually, so I was quite happy with my gigantic intercooler and 80-100F temps.

Also make sure your IAT sensor is calibrated correctly, ie ambient actually reads ambient.

GL sir and I hope we see her back on the streets soon.

[Ether-D]

It won't be long.

I got the head off my parts car and the thing is completely original. All rockers are date stamped 86. All original head bolts, pre recall. The parts car is an 87. Was Elring the original HG manufacturer? Nice cross-hatching in the cylinders. There is almost zero wear on the cam lobes. So I'm gonna take all the rockers from the 87 and put them in the Supervert. Just for the summer while I build the 2.8 out of the block from the 87.

[The Dark Side of Will]

If you're going to take the summer, why stop at 2.7 or 2.8? Brab an M54B30 rotating assembly and build a supercharged 3.0 ;)

[Ether-D]

Does that mean just the crank, or the crank and rods? Cause I'd be down for whatever. If it's not that simple, what all is involved with a 3.0 build? Link?

[The Dark Side of Will]

This is a pretty pricey one, but the M54B30 crank + rods and I'm not sure what pistons. The extra displacement will bump your compression ratio, so I'm not sure if a blower friendly build can be done with stock BMW pistons.

EDIT:

http://www.r3vlimited.com/board/showthread.php?t=317505

[Ether-D]

Oh lawd that looks expensive! I'll just do the 2.8 stroker by way of eta rods and m52 crank. It's at or around $1000 total in parts and machining. And I believe the compression ratio is a smidge lower than m20b25. Don't quote me.

[Q5Quint]

Don't quote me.... but would a m50 would be cheaper than that?

;-)

I think my e30 dreams look like this:

Get supercharger working on ratty 325is.
Ratty 325is eventually explodes or rusts away, or both.
Move supercharger bits over to clean e30 vert
if m20 ever explodes, swap to m50, make a new supercharger bracket.
drive for life, sex all day.

I should have started with a vert but there was a coupe for sale cheap literally just up the street from me. I think I would also m50 before a stroker- I am finding s50+tranny for about $2500 but I havent found any active sales yet. M50 seems to be about $500 lol

example of dreams + likely m3 fender hate:



If you are into building the stroker- go for it for sure. I love the m20 engine stock, but when you can drop in the m50 + cams for around the same price as a quality rebuild, and be moving again within a week, it is a hard argument to compare.

http://www.e30dohc.com/wiki/index.php?title=DOHC_Swap_Basics#What_Are_the_Required_Parts

[Ether-D]

I'll do my full retort later, but I have no love for m50. None. I want to make a m20 that gets it's balls lovingly licked by m5xs.

[Q5Quint]

I am.... worried.... about where we can go with superchargers on m20s based off of other dyno results. The supercharged buick our charger came off of had 240hp and 280tq at 3600rpm at the crank..... but it was 3.8 liters. With mods it would hit 300hp.... but on our smaller 2.5 (or 2.8 if we stroke it out) I think the m90 has the flow in cfm, but it will struggle with the higher pressure ratio ie higher boost required to get those numbers on a smaller displacement engine.

Stock this thing ran 7-8psi on the buick, and with a pulley 11-12psi.... so 12psi on a smaller engine will be no problem but.... but on our smaller engine we will have smaller power. Looking at the efficiency charts~ I dont even think 15psi is actually an option as it is literally off the chart:



If we can hit 240 at the crank, like the buick, I think we will be in job well done territory. +70hp over stock is pretty good. I think the charger is good for more than that- maybe till 350hp based on flow... but you would need to use it on a 5.0 v8 or a 3.2l m engine for that due to leaving the efficiency zone of a 1.5x pressure ratio (8psi btw). After that we are creating more heat from inefficiency than we may be getting back in power.

However- More power to you for sticking with the m20! I didn't mean to come off as a negative nancy, I am just spoiled by $300 engines at a local pick n pull so it is hard to rebuild anything. Black friday deal = 1/2 any engine. 32v northstar or 1.6liter vw bug engine from 1969- they dont care lol.

I have a dollar on a 2.8l stroker m20 with a m90 and a cam hitting 240hp crank at 13psi, about what the buick was doing at 8psi. Most of that is just due to the smaller displacement/ pressure ratio efficiency thing.

[Victell]

How much can heat be brought down with a large intercooler? Maybe get some heat efficiency back?

[Ether-D]

I am.... worried.... about where we can go with superchargers on m20s based off of other dyno results. The supercharged buick our charger came off of had 240hp and 280tq at 3600rpm at the crank..... but it was 3.8 liters. With mods it would hit 300hp.... but on our smaller 2.5 (or 2.8 if we stroke it out) I think the m90 has the flow in cfm, but it will struggle with the higher pressure ratio ie higher boost required to get those numbers on a smaller displacement engine.

Stock this thing ran 7-8psi on the buick, and with a pulley 11-12psi.... so 12psi on a smaller engine will be no problem but.... but on our smaller engine we will have smaller power. Looking at the efficiency charts~ I dont even think 15psi is actually an option as it is literally off the chart:


If we can hit 240 at the crank, like the buick, I think we will be in job well done territory. +70hp over stock is pretty good. I think the charger is good for more than that- maybe till 350hp based on flow... but you would need to use it on a 5.0 v8 or a 3.2l m engine for that due to leaving the efficiency zone of a 1.5x pressure ratio (8psi btw). After that we are creating more heat from inefficiency than we may be getting back in power.

However- More power to you for sticking with the m20! I didn't mean to come off as a negative nancy, I am just spoiled by $300 engines at a local pick n pull so it is hard to rebuild anything. Black friday deal = 1/2 any engine. 32v northstar or 1.6liter vw bug engine from 1969- they dont care lol.

I have a dollar on a 2.8l stroker m20 with a m90 and a cam hitting 240hp crank at 13psi, about what the buick was doing at 8psi. Most of that is just due to the smaller displacement/ pressure ratio efficiency thing.

I'm gonna hit 250chp, but the torque is what I'm loving. I can't wait to see the curve on this thing. I have 6psi now with the big pulley, and was faster (not bragging) than an m50 swap that I ran a bit with. That tells me that I must be at least 190chp (thinking this is conservative, btw). I want a torque monster with a long curve. That would be perfect for DD'ing. HP aint nuthin' but a number.

How much can heat be brought down with a large intercooler? Maybe get some heat efficiency back?

I'm thinking of "deleting" the A/C. I could just use the a/c condenser as the external heat exchanger for the intercooler. Perfect loation, fan attached with on/off button (a/c button) already installed, perfect size. It's killing me to think of getting rid of the a/c though. Somebody make this decision for me...

[The Dark Side of Will]

Oh lawd that looks expensive! I'll just do the 2.8 stroker by way of eta rods and m52 crank. It's at or around $1000 total in parts and machining. And I believe the compression ratio is a smidge lower than m20b25. Don't quote me.

Well... the way HE did it is expensive. You don't need the S52 crank, for example. The M54 unit will do fine. Check eBay out.

As Q5Quint mentioned, every extra cc you can get will help the supercharger work better.

Don't ditch your A/C. It gets just as hot in TN as it does in VA and I will never leave A/C out of a modified car... ever.