Bigger "SSI" system

[Falk930]

Talked to Mr. Eisenmann today, they had a 3.2 in there and still work on details. We discussed a few points: At first he told me, that they will allow a cat option. There will be flanges direct after the collectors, secondary tubes or cat will be offered, O2 bung is planed. They changed design slightly to allow the tubes to be bended in one piece. No way to leave original oil lines, they work on their own backdate oil lines. I personally like the backdated ones better anyway, had build these for my 930 time ago:Oil lines by myself Asked about availability, they plan to get the final version ready this year. Falk

[gliding_serpent]

Originally Posted by Roger 911

Yikes, considering that these might give you 5-10 hp (depending on mods). I guess I'm too cheap. They look nice though.

Roger

At a certain point insanity sets in. I am at 290hp at the crank with my 3.4, depending on what you believe, and hope to cross 300 soon... need to upgrade the ssi's.

Small changes add up, and can be synergistic. 10-15hp on a stock car can be more depending on what it is pared with... but 10-15hp is a fair number to expect. Mind you, you get those same numbers with a stock heat exchanger on our cars... so the crazy part is important...

[White911SC]

Originally Posted by Falk930

Talked to Mr. Eisenmann today,
they had a 3.2 in there and still work on details...

...They changed design slightly to allow the tubes to be bended in one piece....

Falk

One piece tubes is a nice improvement to addresses any concerns about tubes having welds internal to the heat exchangers...(not that it would have been a deal breaker but better safety and reliablility is always appreciated for any component).

Originally Posted by Roger 911

Yikes, considering that these might give you 5-10 hp (depending on mods). I guess I'm too cheap. They look nice though.

Roger

I currently have SSI's which are perfect for my use in almost everyway for my 3.0L SC. But..I'm collecting parts for a 3.5L build which includes Carrera heads. I would be very interested in a thick flange 3.2 version of these 1 5/8" heat exchangers with the assumption the final configuration is compatible with backdated heat routing same as the SSI version I currently have.

Although...if it turns out the 3.5L really needs a 1 3/4" version to reach it's full potential I would strongly consider the Rarley8/M&K headers w/heat as a quality option...

As far as cost, when modifying your P-Car for performance if all related components are not matched accordingly within your build you should also consider the value of lost potential of other upgrades due to mismatched parts.

[Maxhouse97]

I like the long tube headers that increase mid-range torque, in addition to the good heat and classic look.

[stephen1070]

Good afternoon - is there an update on these eisenmann SSI's?

Thanks!

[Lyle O]

I would like to know as well. The Eisenmann web site still only shows the larger version for older engines (F-model, 2.8 & 3.0 race engines), not yet anything for 3.2 G-model...

Etwas neues, Herr Falk?

Besten dank!

[DG624]

OK we know the cost but do we know the benefit? What power increase over stock 3.2L with CAT bypass? I like the look but will it really help?

[gliding_serpent]

Originally Posted by DG624

OK we know the cost but do we know the benefit? What power increase over stock 3.2L with CAT bypass? I like the look but will it really help?

On a car with a muffler, i will take the bet that it is no better than stock. Sure you have equil length primaries that are 31 inch long tube. But with a muffler those benefits are marginal. The key is the primary diameter.

And they will be heavy. Ssi's are a mild weight savings over stock, and most of that is due to the cat.

If you are building a race car, get headers. Skip the heat and save the weight.
If you want heat, stay with stock, even with a pretty hot 3.2 or 3.4.
Any more power, go with flipped 993 headers (for heat), or go with larger 1 3/4 headers.

My honest opinion.

[Jonny042]

Originally Posted by DG624

OK we know the cost but do we know the benefit? What power increase over stock 3.2L with CAT bypass? I like the look but will it really help?

The benefit would be the 42mm primaries vs the 38mm you get with the SSI's (or smaller eisenmann HE's).

So if you were getting (or had) SSI's already they would be a better option for a larger displacement engine, all other things being equal.

[Jonny042]

Do we know if the secondaries are the same size between the SSI, and the two sizes of Eisenmann heat exchangers?

Is secondary diameter a consideration, or is standard big enough for 300+ hp?

[Bill Verburg]

Originally Posted by Jonny042

Do we know if the secondaries are the same size between the SSI, and the two sizes of Eisenmann heat exchangers?

Is secondary diameter a consideration, or is standard big enough for 300+ hp?

Due to firing separation of 240° on each bank, collector size won't be an issue

[gliding_serpent]

Agreed. Primary diameter is key.

[Jonny042]

I contacted Eisenmann and have been really pleased with their correspondence, both from the North American distributor and the home office in Germany.

The pricing is a little better than what we've seen in this thread - there are other factors however as I am in Canada and would have them shipped direct from Germany, so others results may vary.

I myself am beginning to doubt the benefit of them however for my application.... It is long overdue that I start a thread about my engine build, but the short version is it's a 3.2SS with MFI. Hoping for 260-270hp but wouldn't mind more , using Mod S cams (open for debate) 2.7RS space cam/MFI pump, 38mm intake ports, 40mm throttles, plastic stacks bored, and 9.5:1. Nothing groundbreaking.

Due to the MFI my initial plan was to get SSI's made for MFI (with the additional heat exchanger for the thermostat) and use a 2 in, 1 out, dansk sport stainless muffler with the 70mm tip (also set in stone as I don't want to cut my factory made 2.7RS rear bumpers for a second pipe).

The other option is the Eisenmann 42mm HE's and their muffler to match. The 42mm primaries seem well matched to the 3.2 but wonder if the rest of the system is up to the task? The collector/secondary tubes are 50mm regardless of primary size. I'd also have to come up with a manual enrichment system for warm up but that's not insurmountable and may actually simplify things in the long run.

So if I boil it down - is the single outlet muffler going to choke the engine so much that the few extra mm of primary wont be worth the trouble?

[Bill Verburg]

Originally Posted by Jonny042

I contacted Eisenmann and have been really pleased with their correspondence, both from the North American distributor and the home office in Germany.

The pricing is a little better than what we've seen in this thread - there are other factors however as I am in Canada and would have them shipped direct from Germany, so others results may vary.

I myself am beginning to doubt the benefit of them however for my application.... It is long overdue that I start a thread about my engine build, but the short version is it's a 3.2SS with MFI. Hoping for 260-270hp but wouldn't mind more , using Mod S cams (open for debate) 2.7RS space cam/MFI pump, 38mm intake ports, 40mm throttles, plastic stacks bored, and 9.5:1. Nothing groundbreaking.

Due to the MFI my initial plan was to get SSI's made for MFI (with the additional heat exchanger for the thermostat) and use a 2 in, 1 out, dansk sport stainless muffler with the 70mm tip (also set in stone as I don't want to cut my factory made 2.7RS rear bumpers for a second pipe).

The other option is the Eisenmann 42mm HE's and their muffler to match. The 42mm primaries seem well matched to the 3.2 but wonder if the rest of the system is up to the task? The collector/secondary tubes are 50mm regardless of primary size. I'd also have to come up with a manual enrichment system for warm up but that's not insurmountable and may actually simplify things in the long run.

So if I boil it down - is the single outlet muffler going to choke the engine so much that the few extra mm of primary wont be worth the trouble?

MFI is very sensitive to exhaust changes, It's just not very fllexible. You may have to have the pump custom modified to suit whatever you end up w/

[Jonny042]

Originally Posted by Bill Verburg

MFI is very sensitive to exhaust changes, It's just not very fllexible. You may have to have the pump custom modified to suit whatever you end up w/

Or build an MFI test bench and do it myself

I have a 2.7RS space cam which is the commonly used starting point for a large displacement MFI motor (including the factory 3.0RS). I am sure the MFI gurus would like us to think there's some black art to it and they're whittling new custom space cams from fairy dust in their back rooms but I'm pretty sure that's not the case. (edit - would like to be proven wrong on this)

I really should start a thread on the motor build, but the last decision I need to make is camshaft choice. My intake and exhaust paths are pretty well established (with possible exception of primary tube dia), but I need to choose a cam profile for the motor, I am aiming to create a torque curve that is the same shape (but hopefully shifted up on the vertical axis) as that of a 2.7RS. I think that gives me the best chance of hitting the fuel curve the space cam gives me and hopefully keep the tweaking to a minimum.

In other words, building a motor to suit the MFI system, not the other way around. I'd love to hear your thoughts on it.

[Bill Verburg]

Originally Posted by Jonny042

Or build an MFI test bench and do it myself

I have a 2.7RS space cam which is the commonly used starting point for a large displacement MFI motor (including the factory 3.0RS). I am sure the MFI gurus would like us to think there's some black art to it and they're whittling new custom space cams from fairy dust in their back rooms but I'm pretty sure that's not the case. (edit - would like to be proven wrong on this)

I really should start a thread on the motor build, but the last decision I need to make is camshaft choice. My intake and exhaust paths are pretty well established (with possible exception of primary tube dia), but I need to choose a cam profile for the motor, I am aiming to create a torque curve that is the same shape (but hopefully shifted up on the vertical axis) as that of a 2.7RS. I think that gives me the best chance of hitting the fuel curve the space cam gives me and hopefully keep the tweaking to a minimum.

In other words, building a motor to suit the MFI system, not the other way around. I'd love to hear your thoughts on it.

If you have the skills, for large departures from normal parameters most will need the services of Pacific Fuel Injection or similar.

That's why most modern builders will go to one or the other electronic engine management resources.

My experience was w/ a 2.4SMFI, it didn't like exhaust mods on an otherwise stock motor, maybe you'll have better luck

[kent olsen]

Larger exhaust doesn't always equate to more HP and Headers are not always equal length. Racers like Bill know tuning the exhaust to the engine displacement and expected rpm range is critical to a broad HP/Torque range.

[Jonny042]

Originally Posted by Bill Verburg

Due to firing separation of 240° on each bank, collector size won't be an issue

Makes sense when you think of exhaust pulses - one at a time into (and out of) that pipe.

How does this translate to the tailpipe? In other words, will a single 60mm outlet on the muffler be big enough not to cause undue restriction?

I want to keep a stock look to the car and not go with additional pipes (and noise), hence the single outlet.

Perhaps a 2 in, 1 out, with a 70mm tip would be best? And pair well with the 42mm heat exchangers.

[Bill Verburg]

Originally Posted by Jonny042

Makes sense when you think of exhaust pulses - one at a time into (and out of) that pipe.

How does this translate to the tailpipe? In other words, will a single 60mm outlet on the muffler be big enough not to cause undue restriction?

I want to keep a stock look to the car and not go with additional pipes (and noise), hence the single outlet.

Perhaps a 2 in, 1 out, with a 70mm tip would be best? And pair well with the 42mm heat exchangers.

The Porsche H6 has one of the best firing patterns on any engine, it is an even fire design w/ each pulse 240° apart in each collector, when the sides are merged the pulses are still 120° apart, there is some congestion in most muffler designs, but that isn't the issue w/ MFI. The issue is that MFI is fairly tightly and rigidly constrained wrt operating parameters. Deviate from those parameters and the system just doesn't respond well. Minor changes to a stock engine such as muffler changes alone move the operating envelope uncomfortably close to the edge, bigger changes such as cam or displacement changes will expand the envelop even further, this is where places like Pacific become invaluable. An owner just can't fiddle the knobs far enough, internal changes to the MFI pump become mandatory for a good running engine.

Pipe size is correlated to displacement and rpm range, it's like the story of Goldilocks and the porridge, not too small and not too big is what is desired and what's right for Baby Bear isn't the same as what's right for Papa Bear. SSI primaries are 35mm(same as oe was)this is fine for up too ~3 liter & ~6800rpm, you could use these on a 3.6 but above ~5500rpm the small pipes will be choking the engine. On a 2.4 SSI are probable ya tad big at the lowest rpm and just right at the top, as the displacement increases the sweetest spot moves down the rev range for a given pipe size. By the time you get to 3.2 and especially for 7k+/- power range you need to increase the pipe size over what is found in SSI the 42mm pipes discussed here are great for that app, as you go to 3.6 and 3.8 and 4.0 or as the revs go to 7.5k or 8k or more the pipe size again needs to go up, these engines want 45-47mm pipes. This is only for max power at max rpm, some motors are tuned for more midrange and can profit from somewhat smaller pipes.

No matter what the intake and exhaust need to be in harmony for best results.

[Jonny042]

Originally Posted by Bill Verburg

No matter what the intake and exhaust need to be in harmony for best results.

Thanks, Bill, for the (as usual!) detailed and useful reply. I've been doing a little more research (too much information, mostly subjective) about single outlet sport mufflers and it seems the lack of a second outlet tip doesn't cost much power.

As for harmony from one end of the engine to the other, I'll have MFI stacks with a small diameter at 39, throttle plates at 40.5 (with thinner profile on the shafts for greater flow), intake ports at 39 matched to the throttle bodies, and exhaust ports at 35mm if I choose SSI, and perhaps a little bigger if I go with Eisenmann.

These dimensions are up against physical limits of the MFI stacks and throttle bodies, but IMO should suit a 3.2SS with a 5000rpm torque peak and a 7000rpm rev limit, with a torque curve similar to that of a 2.7RS.

With my objective of creating an engine with a similar VE to the 2.7RS at a given RPM, the space cam should be a close starting point (albeit with some gross volume changes in fuel delivery at the plunger collars). I can tweak the fuel delivery based on datalogging the AFR, engine RPM, and throttle position.

NOW.... back on topic!! I got a message from Eisenmann today and sounds like there are promising developments with their 3.2 Carrera system with catalytic converters!! I'm sure there will be new news soon.