Performance Mods to stock CSI - Most bang for the buck.

[tripower]

I know this topic has been brought up before but I want to bring it up again but mostly in terms of a very strick price limit.

If you had $2000 to spend on the engine alone where would you allocate that money to a stock CSI engine and what kind of RWHP do you think you could achive for that kind of money. Keep in mind that you could do some or most of the work yourself with a well stocked garage only farming out stuff like machining parts and such.

 

[decoupe]

$2,000 question

My guess would be a swap to a 3.5 litre like the one below. If you can find it for less, great. You would still have another $1,000 to spend on other goodies (cam change, porting, headers etc).

Assuming you have pulled the transmission be sure to have the flywheel lightened ($150) by 40% - cheap performance mod based on reducing rotating mass.

Product SKU Description Price
Special 6- M30 Engine-3.5 liter Euro "L" block
spec6 M30 Euro "L" block engine $1,000.00
M30 (big 6) Euro 3.5 liter "L" block. Complete engine including injection, alternator, starter etc.
The "L" block has the larger 93.4mm Euro bore.

 

[x_atlas0]

Higher comp pistons would help, since it bumps up power by about 10-20%. (8:1->10.5:1) This change requires premium gas, however.

 

[AndyM]

Unless you have some compelling reason to keep it, don't waste your money on the stock csi motor, really. The csi 3.0 is already 9.5:1 so its really not worth the money for custom pistons to bump up the compression. If you are inclined to stay with the 3.0 and the short block is still in good shape, then I'd spend the money on electronic ignition, a mild cam, head and intake porting and a header with free-flow exhaust. You should be able to get the D-Jet to run that with some tweaking since the new Schricks are pretty mild on the duration, but make up for it with increased lift. You may gain 20-30 hp. I don't know what the RWHP would be -- probably still less than 200 at the wheels.

On the other hand, if you really want a noticeable performance upgrade, I would suggest getting a 3.5 block and start there. I just built mine for well under $2k with a Schrick cam and 9.5:1 pistons (or thereabouts) farming out the machine work (block hone, valve job, rebuilt rods) and assemblying everything myself (including the valvetrain). This includes all new bearings, rockers, timing set, oil pump, etc. -- basically everything was renewed. It will blow the doors off the 3.0 that was in there. The only caveat is whether you can get it to run with the D-Jet. I didn't even try to run the D-Jet on mine and went straight for the programmable ECU. Unfortunately, that adds extra $$$ that would probably put you above the $2k budget. I think you can get the D-Jet to run this combo with some tweaking (increased fuel pressure, MPS adjustments, temp sensor resistors, etc.), but you'd need someone knowledgeable to get it set up right.

 

[velocewest]

$2,000? I'd find a used M30B35 with all the Motronic accoutrements, add a Schrick 284, lighten the flywheel, and install an EAT chip. With some diligent shopping that's within the realm of $2,000, and it's simple, quick to accomplish with minimal shop time and guaranteed to deliver reliable oomph. The M30B35 was 218 HP in US trim, so the cam and the chip should get you to 250-260 HP, with a big increase in torque that you'll really feel when you hit the loud pedal.

 

[AndyM]

True, but then you're stuck with that goofy Motronic intake manifold and you still have to deal with the brake booster clearance issues. Not insurmountable by any means, but very distracting from an otherwise attactive stock engine bay IMHO.

 

[tripower]

Engine swaps

Seems like the engine swap is a very popular performance mod. I was at a show this past weekend and a guy had an E9 Coupe. He had an e36 M3 motor that Korman had dropped in and said it was pushing out over 300+ HP. In a car that light that is a monster amount of HP.

 

[tripower]

Back to the original question...

.... If one were so inclined how much HP could you eek out of the original CSI engine?

 

[x_atlas0]

Re: Back to the original question...

.... If one were so inclined how much HP could you eek out of the original CSI engine?

With enough time and money, anything is possible, especially if you put on a huge turbo. With the TCD kit, the M30 has made a good 360rwhp and 400ft-lbs of torque. Of course, your numbers would be smaller, as detonation (possibly) could be an issue with your CSi high-comp pistons, and the displacement is significantly reduced.

If you have a budget of 2k, then you have to ask yourself... "How important to me is originality?"

 

[AndyM]

You really can't beat a turbo or supercharger for the most bang for the buck. Then again, you'll probably be rebuilding the 3.0 within the first 5k miles so it may be false economy. Plus, you'll need to figure out the fuel injection since that won't work with the D-Jet.

If you want to keep it somewhat original, I wouldn't worry so much about max hp ratings. I'm sure there are folks out there who can squeeze 275-300hp out of a naturally aspirated 3.0 -- but it will only make that power above 6500 rpm. Great for a track car, but not so useable on the street. My motor has a pretty mild cam which "comes on" around 2,500 and pulls hard to around 5k. It has power to spare, but I bet its only about 240-250 hp at the crank. I'm going to dyno it at some point, but haven't gotten around to it. I'm guessing the 3.0 would be about 220-230 hp with similar modifications.

I guess you kind of need to figure out what your goals are and go from there. For the street, a nice, fat torque curve will give you great acceleration and passing ability. You'd probably be really happy with the extra 40-50 hp you'll get from the suggestions above (cam, headers, port work, ignition, flywheel). Just don't overdo it on the cam or it'll end up idling like a POS and will be a dog off the line.

 

[tripower]

Heads

I'm resurrecting this thread in the hopes of looking more indepth at how I can glean more HP out of the original CSI engine. So specifically what can I do to the original cylinder head (port, polish, etc.) to see significant gains in HP or should I look at a new cylinder head (specifically for track use).

 

[M635forever]

I´m putting a M106 (m30B34 with oilcooled pistons) and a KKK27 turbocharger in my -75 3.0Csi(the 5th last, of the E9 production)!
My goal is about 390hp and 700Nm! :lol:
The chassie is getting stiffed up and maby getting a rollcagen in the coupe!
My father got a M30B34 218hp and 5 speed Getrag 260 from a Euro M535 in his E9!
And it runs really great! :shock:

 

[tripower]

I´m putting a M106 (m30B34 with oilcooled pistons) and a KKK27 turbocharger in my -75 3.0Csi(the 5th last, of the E9 production)!
My goal is about 390hp and 700Nm! :lol:
The chassie is getting stiffed up and maby getting a rollcagen in the coupe!
My father got a M30B34 218hp and 5 speed Getrag 260 from a Euro M535 in his E9!
And it runs really great! :shock:

Sounds very cool. I want to keep mine NA, so no FI.

 

[x_atlas0]

If you want to keep the CSi injection system, I think you are confined to the older head.

If staying NA, there are some things you can do:
Headers
320i intake runners on your log-style intake manifold
P&P
Larger valves
284 cam

The rest of the limitations are mostly tied to the CSi injection system and the lack of tuning available for it. If you switched to Motronic (which can be used with the log intake, it just takes some tricky wiring) you would be able to have many people retune the car for any changes made, like a bore and stroke, as well as high comp pistons. To get the same effect, I suppose you could decrease Vc in the head, rather than dissassembling the bottom end.

Like was said before, the best bang for the buck would be a B35, Motronic, a 284, headers, and an EAT or Conforti chip. I'd put that in with 320i runners and your old manifold.

I have a dyno of a B35 with the log manifold, 320i runners, and a Conforti chip. It put down ~180 rwhp and ~200 rwtq. Factoring for drivetrain loss, this translates to about 210 crank hp and 240 crank tq.

 

[jmackro]

What about CARBURETION on a 3.5 ?

All this discussion of increased displacement - going to a 3.5L - has gotten me thinking. My old 2800CS has dual carbs (Weber downdrafts with JAM adapters for the stock air cleaner - NOT DCOE sidedrafts). Would that setup - probably with some revisions to the jetting - work with a 3.5? Would my 2.8L manifold fit the 3.5 head?

Yea, I understand that aftermarket EFI, or even later factory EFI, would probably produce more HP. But, hey, increasing the displacement by 25% has got to produce some noticable gains, even if it isn't optimal. And it seems a shame to add all that wiring & plumbing to the simple underhood area of my 37 year old car.

Thanks

 

[x_atlas0]

So you have the dual 38's? I don't know if that would give you enough breathing room, since the 38's tend to die out up top with the 3.0L block. There is only so much you can re-jet. An upgrade to double 40 DCOE's or triple 40's would give you a lot more breathing room.

 

[velocewest]

Re: What about CARBURETION on a 3.5 ?

All this discussion of increased displacement - going to a 3.5L - has gotten me thinking. My old 2800CS has dual carbs (Weber downdrafts with JAM adapters for the stock air cleaner - NOT DCOE sidedrafts). Would that setup - probably with some revisions to the jetting - work with a 3.5? Would my 2.8L manifold fit the 3.5 head?

Yea, I understand that aftermarket EFI, or even later factory EFI, would probably produce more HP. But, hey, increasing the displacement by 25% has got to produce some noticable gains, even if it isn't optimal. And it seems a shame to add all that wiring & plumbing to the simple underhood area of my 37 year old car.

Thanks

If you're willing to take the leap of faith -- pick up a set of rebuilt original Zenith INAT carbs. Those will feed a 3.5 no problem. 32/36's are too small for a 3.0, and 38/38's are marginal and get crap fuel economy.

 

[velocewest]

Re: Heads

I'm resurrecting this thread in the hopes of looking more indepth at how I can glean more HP out of the original CSI engine. So specifically what can I do to the original cylinder head (port, polish, etc.) to see significant gains in HP or should I look at a new cylinder head (specifically for track use).

So, what is the reason for keeping the original engine? The D-Jet is well documented to be less than ideal for modding.

The 3.5 block gets you an instant boost of torque (the real seat of the pants improvement) for no work at all.

A stock 3.5 running late L-jet will be a noticably more powerful engine than a D-jet 3.0, get equivalent or better fuel economy, look almost identical and could be in your car and running for under $1,000. With a $1500 limit you could probably get a performance cam and headers in the mix. With a little more expense and not too much more work, you could install MegaSquirt and have tuneable FI that could improve both power and economy, eliminate the intake restriction of the AFM, still look more or less stock, and opens the door to pretty much any mechanical mods you want. Peter Florance from the FirstFives board is becoming a supplier of MS for L-jet cars (and Motronic, for that matter), offering a nearly plug-and-play setup.

I'm not criticising your choice, it's you car and your call. I'm just trying to suggest that for all it's goodness in the 1970's, a d-jet 3.0 is not the best base for performance in 2007, and might be a more expensive base than other options.

 

[tripower]

Re: Heads

So, what is the reason for keeping the original engine?

I'm cheap and lazy.

The D-Jet is well documented to be less than ideal for modding.
The 3.5 block gets you an instant boost of torque (the real seat of the pants improvement) for no work at all.

What's the reason with you guys always suggesting an engine swap as the only way to get any real power out of these cars?

A stock 3.5 running late L-jet will be a noticably more powerful engine than a D-jet 3.0, get equivalent or better fuel economy, look almost identical and could be in your car and running for under $1,000. With a $1500 limit you could probably get a performance cam and headers in the mix. With a little more expense and not too much more work, you could install MegaSquirt and have tuneable FI that could improve both power and economy, eliminate the intake restriction of the AFM, still look more or less stock, and opens the door to pretty much any mechanical mods you want. Peter Florance from the FirstFives board is becoming a supplier of MS for L-jet cars (and Motronic, for that matter), offering a nearly plug-and-play setup.

I'm not criticising your choice, it's you car and your call. I'm just trying to suggest that for all it's goodness in the 1970's, a d-jet 3.0 is not the best base for performance in 2007, and might be a more expensive base than other options.

I just don't agree. Some guys actually want to keep their cars stock for a reason. And I think there are some smaller things that can be done to the car like opening up the intake, exhaust, putting in a hotter cam, etc. that are far less radical and can allow me to appreciate the car as is. I already know what BMW can do in 2007. Believe me my E46 M3 gives me all the HP and Torque that I can handle I don't need reinvent the CS to find that out.

 

[velocewest]

Re: Heads

I'm cheap and lazy.

I resemble that remark!

What's the reason with you guys always suggesting an engine swap as the only way to get any real power out of these cars?

It's not the only way, but the 3.5 swap is arguably the most cost-effective way to add power. Good used 3.5's for $300-$500 are not rare, so starting there puts you well ahead of the 3.0 or 2.8 for the equivalent of a head refresh and a gasket set.

I just don't agree. Some guys actually want to keep their cars stock for a reason. And I think there are some smaller things that can be done to the car like opening up the intake, exhaust, putting in a hotter cam, etc. that are far less radical and can allow me to appreciate the car as is. I already know what BMW can do in 2007. Believe me my E46 M3 gives me all the HP and Torque that I can handle I don't need reinvent the CS to find that out.

I wasn't intending to suggest you should shoot for the performance equivalent to a modern car. I was just pointing out that the options for shade tree performance tweaking circa 2007 can far exceed the capacity of the d-jet system, so there's benefit to be had by opting for alternate engine management. Not owning a d-jet car myself, I'm relying on anecdotal evidence. Like I said, your car, your choice. For me, tweaking an older car is more engaging, and fits my cheap nature better. Your e46 is worth more than all three of my cars combined!