Trying to summarize Super eta (S-eta) stroker build info.

[phenryiv1]

I have a 1988 (Super) S-eta that I am considering turning into a very mild stroker. I have pulled out the parts of http://www.r3vlimited.com/board/showthread.php?p=920959#post920959 that I think apply, and have re-posted them in this post. Because that thread started off as mostly an upgrade thread to the motronic 1.3, it got a bit confusing, and I think it tried to answer too much, dealing with i, e (eta), and s-eta motors all in the same thread.

Several points seem to be slightly off with what I have read elsewhere in the forums, including that thread. I will edit this post to try to ask clarifying questions about the concerns that I have. Any help would be appreciated.

As I already have the motronic 1.1, i exhaust, and domed s-eta pistons, my build should be greatly simplified versus the pre-88 builds, correct?

Now, on to the real questions. Here is what I think it the relevant portion of the original post:

1988 super eta, seta

Parts Needed:
i intake manifold, i throttle body, i 173ecu (computer in glove box), i cam, i double valve springs, i AFM, 17.5# injectors (preferred), i fuel pressure regulator (see Note 3?)

Optional Parts:
i dual exhaust, i radiator and expansion tank, i single fuel pump fuel tank and fuel lines, i flywheel, i transmission with drive-shaft(Must use original center support bearing), i differential(4.10 from ix), i brake booster, i 90amp alternator (recommended)

Based on what I have read, some things that are listed as "optional" are really more required than what is losted above. I have moved or added the bold entries. Am I missing anything?

Head Piston Options:

i head with s-eta pistons yields 8.5:1 compression with great torque and great acceleration
Note 7: The 1988 325,e,es 2.7 (super eta, seta) which is the only year with 2.7 domed pistons that mate with the i head and have proper compression for NA applications.

This woud be my preferred setup.

Notes

Notes 1, 2, & 5: Once 1.3 Moronic is swapped in you will rev past 5300rpm so you will need to install the 7000rpm i tachometer. None of the i parts will increase your rev limit (5300rpm) without the 173ecu 1.3 Motronic up-grade(6300rpm). For 7000+ rev limit check out various performance chips. Double valve springs are preferred for high rev applications but you can run the stock single valve springs under 5300rpms until you are ready to take the head off

This only applies if you switch ONLY the motronic unit, not if doing an actual stroker (i head/cam) install, correct? So if I am doing a stroker build, isn't this note is essentually moot? I'd think so, because I will already be digging into the top end, so I need to do the dual valve springs when I do the i head and the 1.3 conversion.

Also,

Note 6: After upgrading to 1.3 Motronic you may want to move your power curve up, so try the i cam or bigger in the eta head. The eta head will need to have oil passages drilled for the 3 extra cam journals at a knowledgeable machine shop so you can put the 7 bearing i cam or bigger in the eta head.

09/87 and newer build dates (basically the S-eta 1988s) do not need to worry about this, correct? Also, i will be using an i head (as opposed to an eta), so won't I be fine?

Did I understand that correctly?

Note 3: A 30amp fuse will be needed in the fuse box for the fuel pump.

A post by etaSport indicated that an i (or larger) fuel pump may not be necessary, even with 17.5# injectors. Did I read that correctly? Edit: I may have mis-read that. I now think he was referring to the fuel pump, not the injectors.

Note 4: 1.3 Motronic wire harness is larger then 1.0basic Motronic harness so the inlet hole on the firewall passenger side will need to be slightly enlarged.

This does not apply to 1988 eta owners, does it? The Motronic 1.1 that we have already has the correct plug, right?

Note 8: (e Crank, e rods, 88 super eta pistons, i head) is the most preferred and valued combination with stock bmw parts.

This is among non-super eta owners, correct? S-eta owners might as well do the cam, ecu, springs, and anything aft of the motor, as they see fit.

Some more references (for me) from the first post:

Note 12: Here is quote from Wikipedia.com supporting the 2.7i and explaining the 1.3 upgrade.

For the 1988 model year, the eta cars got a refresh from the factory. This included a newer Bosch Motronic version with adaptive idle control, a 325i head casting with the larger valves, ports, revised combustion chambers and water jacket, new pistons to fit the 2.7 L stroke with the 2.5 L head, a dual exhaust system and a 5300 RPM rev limit. Though it only made slightly more power in stock form, it could be easily boosted by bolting on a 325i head, a complete 325i intake manifold and throttle and plugging in the 325i engine control unit. Depending on which cam, chip and intake is used, the combination can make over 180 horsepower with the stock compression ratio.

In aftermarket modifications that are inspired by custom versions of Alpina and AC Schnitzer, the long-stroke eta engine block is often combined with a 325i head to a so-called 327i that combines the high low-rev torque of the eta with the top-range power of the 325i.

Links:
Old 2.7i thread with pictures
http://www.e30tech.com/forum/showthread.php?t=39960

Wikipedia
http://en.wikipedia.org/wiki/BMW_M20

Haynes Manual
E30ManualHaynescomplete.pdf (application/pdf Object)

1.1/1.3 Motronic Manual
DME_1.1_1.3.pdf (application/pdf Object)

1983-1992 Wiring Diagrams And Troubleshooting Manuals
http://shark.armchair.mb.ca/~dave/BMW/e30/

Dealer Manual
http://ee1394.com/bmw/docs/factory/repair/en/index1.htm

M3 Repair Manual
http://pagesperso-orange.fr/s14/index.htm

[TexasTerp]

As I already have the motronic 1.1, i exhaust, and domed s-eta pistons, my build should be greatly simplified versus the pre-88 builds, correct?

Simplified, Yes. You will still have plenty to do though.

Now, on to the real questions. Here is what I think it the relevant portion of the original post:

Based on what I have read, some things that are listed as "optional" are really more required than what is losted above. I have moved or added the bold entries. Am I missing anything?

You HAVE to have the Motronic 1.3 #173 ECU for the application, you can not do the 2.7i without it. The Dual exhaust is a definite, the rest of it seems appears to be something that I would highly recommend. When I planned my 2.7i seta build I started with a 325i car and was adding the bottom end. I would add as many "i" parts to the car as possible, it will handle the power better. Maybe someone else can help more on that.

This only applies if you switch ONLY the motronic unit, not if doing an actual stroker (i head/cam) install, correct? So if I am doing a stroker build, isn't this note is essentually moot? I'd think so, because I will already be digging into the top end, so I need to do the dual valve springs when I do the i head and the 1.3 conversion.

You MUST HAVE the motronic 1.3 #173 ECU in order for the stroker to work correctly, it is the ECU that regulates your RPM limit and the standard 1.1 software with the 5300rpm limit will absolutely hinder performance, regardless if the hardware is equipped to handle the higher rpms.

09/87 and newer build dates (basically the S-eta 1988s) do not need to worry about this, correct? Also, i will be using an i head (as opposed to an eta), so won't I be fine?

Did I understand that correctly?

This has nothing to do with model years and everything about the actual head that you will be using. Since you are using a full "i" head (885 cast, cams, valve springs etc) you will be fine and don't need to do anything in that department.

A post by etaSport indicated that an i (or larger) fuel pump may not be necessary, even with 17.5# injectors. Did I read that correctly?

not sure on this one, hopefully someone else can help here

This does not apply to 1988 eta owners, does it? The Motronic 1.1 that we have already has the correct plug, right?

Yes, the Motronic 1.1 harness and the 1.3 harness is the same the only difference is the ECU software.

This is among non-super eta owners, correct? S-eta owners might as well do the cam, ecu, springs, and anything aft of the motor, as they see fit.

Wrong! The only difference between the "e" and "seta" setup is the pistons which create different compression ratios. The absolute best setup of stock bmw parts requires a complete "i" head (885 cast, cams, springs etc) and the 173 ECU, you will NOT find a better combination in any setup regardless of eta or seta pistons.

[phenryiv1]

Thanks for the response!

Simplified, Yes. You will still have plenty to do though.

I don't doubt that one bit. :D

You HAVE to have the Motronic 1.3 #173 ECU for the application, you can not do the 2.7i without it. The Dual exhaust is a definite, the rest of it seems appears to be something that I would highly recommend. When I planned my 2.7i seta build I started with a 325i car and was adding the bottom end. I would add as many "i" parts to the car as possible, it will handle the power better. Maybe someone else can help more on that.

-and-

You MUST HAVE the motronic 1.3 #173 ECU in order for the stroker to work correctly, it is the ECU that regulates your RPM limit and the standard 1.1 software with the 5300rpm limit will absolutely hinder performance, regardless if the hardware is equipped to handle the higher rpms.

Maybe my first post was unclear...

In the original thread, very little was listed under the 1988 S-eta as "required," primarily because the original thread started out as JUST a thread about the motronic 1.3 swap more than a full-on stroker thread. What I did was take the parts associated with a stroker build from the "recommended" list and move them into the "required" list, because the point of THIS thread is to discuss the stroker build- not just a motronic 1.3 install.

Because the basic premise of my thread is to build toward a stroker (as opposed to just the Motronic install), I have more parts required and less that are optional.

For example, regarding just the motronic swap, the original post noted that "you can run the stock single valve springs under 5300rpms until you are ready to take the head off." This was based on JUST an ECU swap. Since this thread assumes that you WILL take the head off (to swap on the i head), there is no real reason to retain the single valve springs. Thus, I moved i valve springs from the recommended list to the required list. Make sense? Clear as mud?

Also, since my 88 already has the dual ("i") exhaust (as do ALL 1988 S-etas, I believe), that need to swap in the i exhaust is moot. Since this thread ONLY deals with 88 super etas, it is an unnnecessary item on the list, but I left it in the event that some 1988 eta cars still had single ("e") exhaust.

This has nothing to do with model years and everything about the actual head that you will be using. Since you are using a full "i" head (885 cast, cams, valve springs etc) you will be fine and don't need to do anything in that department.

Okay. I was a bit unclear on that. The original thread discussed drilling holes, but again, that was not specifically tailored toward the 1988 super etas, which already have the 885 head. (Right?!?)

not sure on this one, hopefully someone else can help here

I may have mis-read that. I now think he was referring to the fuel pump, not the injectors. (Edited first post)

Yes, the Motronic 1.1 harness and the 1.3 harness is the same the only difference is the ECU software.

I went back to the original post and saw this:

For the 1988 model year, the eta cars got a refresh from the factory with Bosch Motronic 1.1/1.3 Adaptive fuel injection a modification that adjusts the idle speed of a cold engine and a 6200 redline. It already has 1.1/1.3 Motronic wire harness and sensors.

You can click in a 325i,is,ix ecm and it would have a higher i rev limit.

But all it is needing is double valve springs to survive the higher rpms or something may break.

That clarifies a little more.

Wrong! The only difference between the "e" and "seta" setup is the pistons which create different compression ratios. The absolute best setup of stock bmw parts requires a complete "i" head (885 cast, cams, springs etc) and the 173 ECU, you will NOT find a better combination in any setup regardless of eta or seta pistons.

So for the 88 super eta, which already has the 885 head and the 1.1/1.3 harness, the i exhaust, and the domed pistons, the lists needed is still:

• i intake manifold,
• i throttle body,
• i 173ecu (computer in glove box),
• i cam,
• i double valve springs,
• i AFM,
• 17.5# (or 19#) injectors (preferred), and
• i fuel pressure regulator

[884door]

Don't know if its been discussed but you need the little brake booster vacuum line thing because the I intake manifold has 2 vacuum ports instead of 1. Either that or maybe plug the extra port

[phenryiv1]

Don't know if its been discussed but you need the little brake booster vacuum line thing because the I intake manifold has 2 vacuum ports instead of 1. Either that or maybe plug the extra port

Good point.

[884door]

Also forgot to mention, my fuel pump on my SETA is identical to every 325i pump I have seen so I don't think that needs to be changed.

[phenryiv1]

Also forgot to mention, my fuel pump on my SETA is identical to every 325i pump I have seen so I don't think that needs to be changed.

How about the FPR and the injectors?

[Flash]

If you have a super eta, this is all you need period....

325i 173 ECU
325i inner valve springs
325i cam
325i intake manifold
325i throttle body
325i throttle position switch
325i intake bellows
325i air flow meter
325i 3.0 fuel pressure regulator
325i vacuum line from brake booster, to bellows, and to throttle body side



thats it, nothing more, nothing less.
If your head is only drilled for 4 journals its like 20 bucks at a machine shop to get the additional holes drilled. You need a timing belt and tensioner, head gasket set, head bolt set, and water pump. Thats it.

Im still surprised that with all this information available there is still so much misinformation.

THIS is a definitive list for the super eta, its tried and true, other parts eliminated via realoem, you already have 325i injectors, wiring harness, pump etc...

[884door]

How about the FPR and the injectors?

You need both from a 325i.

[phenryiv1]

If you have a super eta, this is all you need period....

325i 173 ECU
325i inner valve springs
325i cam
325i intake manifold
325i throttle body
325i throttle position switch
325i intake bellows
325i air flow meter
325i 3.0 fuel pressure regulator
325i vacuum line from brake booster, to bellows, and to throttle body side



thats it, nothing more, nothing less.
If your head is only drilled for 4 journals its like 20 bucks at a machine shop to get the additional holes drilled. You need a timing belt and tensioner, head gasket set, head bolt set, and water pump. Thats it.

Im still surprised that with all this information available there is still so much misinformation.

THIS is a definitive list for the super eta, its tried and true, other parts eliminated via realoem, you already have 325i injectors, wiring harness, pump etc...

Thank you for this list.

On the donor, where should I look to pull the throttle position switch?

Also, what is the best way to pull the 173? Is it under/behind/above the glove box?

[Flash]

The TPS is under the throttle body, the ECU is held on by using a 10mm socket, about 6 inches of extension and a ratchet, above the glove box.
You already have the correct injectors, do yourself a favor and send them to cruzin performance to get rebuilt for CHEAP and correctly.
Ive done this swap on about 20 cars for people, BTDT, but its a complete list.
Only other things i forgot were oil, filter, and coolant (phosphate fee), with distilled water.
If you are a newbie, make sure to bleed the coolant :D

[phenryiv1]

The TPS is under the throttle body, the ECU is held on by using a 10mm socket, about 6 inches of extension and a ratchet, above the glove box.
You already have the correct injectors, do yourself a favor and send them to cruzin performance to get rebuilt for CHEAP and correctly.
Ive done this swap on about 20 cars for people, BTDT, but its a complete list.
Only other things i forgot were oil, filter, and coolant (phosphate fee), with distilled water.
If you are a newbie, make sure to bleed the coolant :D

Thanks a bunch for the help. Half of the stroker threads deal with putting eta parts into an "i" car, and 45% deal with adding the "i" top end to an eta car. The other 5% don't specify.

There is a TON of info here on building the motors, but VERY little info out there that clearly says where the user started- meaning, did they start with an i, e, or s-eta on the build.

While everyone says that the 1988 S-eta seems to be the EASIEST one to build, the HOW to build (specific to an s-eta) is really hard to find in the midst of all of the i and e information.

[Wh33lhop]

Yeah, I couldn't believe that no one had mentioned the seta has the right head until a few posts ago.

For further reference: http://en.wikipedia.org/wiki/BMW_M20#Super_Eta_based

Super Eta based

The easiest is to start with a September 1987 onward Super Eta and installing a 325i cam and springs, a complete 325i intake manifold and throttle and plugging in the 325i engine control unit. Depending on which cam, chip and intake is used, this combination can make 180-200hp with the stock 8.5:1 compression ratio and will rev to 7500rpm.

(not sure I'd go to 7500)

Shameless plug, I will probably have a 173 with a mark d clone and 19lb injectors for sale soon.. ;)

[phenryiv1]

Yeah, I couldn't believe that no one had mentioned the seta has the right head until a few posts ago.

UGHHH...I can't believe that was not in my first post. I know that the S-eta already has the 885 head (the "i" head") from the factory. I thought it was in there, btu in looking back, I don't think that I actually SAID that in the post.
Edit: Okay, it IS in there but it is buried in a wikipedia quote that is buried in another post that I quoted in my wall of text.

For further reference: http://en.wikipedia.org/wiki/BMW_M20#Super_Eta_based

Super Eta based

The easiest is to start with a September 1987 onward Super Eta and installing a 325i cam and springs, a complete 325i intake manifold and throttle and plugging in the 325i engine control unit. Depending on which cam, chip and intake is used, this combination can make 180-200hp with the stock 8.5:1 compression ratio and will rev to 7500rpm.

(not sure I'd go to 7500)

Shameless plug, I will probably have a 173 with a mark d clone and 19lb injectors for sale soon.. ;)

Send me a PM when you get ready to sell. Depending on where I am in my build, I may be interested.

[phenryiv1]

Someone on e30tech mentioned the Crank Trigger Wheel and thermostat housing from an "i" as well.

I have never heard of the first item being necessary, and can't figure out why the second one would be.

Thoughts?