Latest Project - Headers

[911st]

Brian,

Again, congrats's and thanks for the answers.

A different sound makes sense. An equal length is going to reduce the magnitude of the exhaust events so there is less high's because of the better pulse timing. The exhaust will come out more as a flow than a pulse.

Compare two straight pipes off equal length headers on a NA race car to a system where they are merged and you get basically the same effect. Even with no muffler the sound level drops.

The rpm shift should not effect the validity of the TQ numbers much. Just shift them a bit. However, moving the Hp peak up 250rpm would mathematically raise the HP numbers about 5% above there true level.

Thus, the system has either moved the HP peak up 250rpm or there was an error in the measurement.

Still, TQ increased from 315 to 349 ft lbs or 11%. Thus, HP increased at least 11%.

Anyway, I think your conclusion that TQ is up 25# and HP 30 is probably very close.

I love trying to figure things out and what dynamics' might be at work.

Studying SSI v stock HE's on a 3.2 the largest increase in VE was about 5% and only over about a 1000rpm range. Here we see a 10% increase over a large range.

Thus, it could be there is more than one factor at work. Most of which should be from the better design.

Part of it is the increased VE that comes from equal length headers as we expect but that is probably not more than about 5%.

Second, and I am only guessing, but another part might be that the same thing that makes it sound different is letting more exhaust gasses to make it through the turbine and thus delay the point where the K27-7200's turbine begins to choke.

This is kind of what a K27-7006 turbo dose. It has an smaller compressor than a 7200 but its larger hot side not only reduces back pressure but also dose not choke as early allowing it to spin the compressor wheel a bit faster and hold boost a bit longer. Such an improvement can be good for about 20hp by its self.

However, here we get the early boost response of a 7200 turbine with the top end of a 7006.

Cool stuff.

Something else that is interesting. Note the 'lean surge' when going to WOT. AFR goes from about 14.5/1 to about 16/1. Also, it stays to lean for max TQ/HP.

A vaccum sensing WUR like the 3.0 turbos had instead of the 5psi acceleration enrichment of the 3.3 turbo could make for a noticable improvement in this area.

I was able to do this with my custom WUR and throttle response and pre boost power improvement was quite noticeable.

Originally Posted by RarlyL8

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[JFairman]

Originally Posted by WERK I

I seem to recall B&B made their claims off an '87 930. I'll see if I can find the literature that claim with the headers. The graph below is off their web site and is the current claim, but no test mule info is there. The important thing that I took away after that cussed-installation, is the response was so much better with the B&B's compared to the factory headers with J-pipe. By "response" I mean the turbo spooling curve had been lowered by about 400RPM.

Ok, now did you have the better euro heat exchangers or the POS choked up heat exchangers that came on USA cars before 1986 when you switched to B&B?

If you had the better euro heat exchangers did you use the same muffler that was on the stock system or the better flowing 3" inlet/outlet B&B muffler? I ask because a muffler with lower backpressure makes alot of difference in performance.

You would have to put whatever muffler was on your factory headers onto the B&B headers to make an accurate measurment of how much power the B&B headers made by themselves.

I still say with nothing else changed on a CIS 930 that has the better euro or 1986-'89 USA heat exchangers (which are the same)... and then bolt on
B&B headers with the SAME muffler you were using before, you will only gain around 5-8 horsepower with boost arriving a little earlier because of the shorter header tubes.
The B&B headers with heat exchangers also weigh less than the origonal heat exchangers.

Anotherwords the "44 horsepower increase with B&B headers" is the usual exaggerated marketing you always see with mass produced high performance street car products like that.

[WERK I]

Originally Posted by JFairman

Ok, now did you have the better euro heat exchangers or the POS choked up heat exchangers that came on USA cars before 1986 when you switched to B&B?

If you had the better euro heat exchangers did you use the same muffler that was on the stock system or the better flowing 3" inlet/outlet B&B muffler? I ask because a muffler with lower backpressure makes alot of difference in performance.

You would have to put whatever muffler was on your factory headers onto the B&B headers to make an accurate measurment of how much power the B&B headers made by themselves.

I still say with nothing else changed on a CIS 930 that has the better euro or 1986-'89 USA heat exchangers (which are the same)... and then bolt on
B&B headers with the SAME muffler you were using before, you will only gain around 5-8 horsepower with boost arriving a little earlier because of the shorter header tubes.
The B&B headers with heat exchangers also weigh less than the origonal heat exchangers.

Anotherwords the "44 horsepower increase with B&B headers" is the usual exaggerated marketing you always see with mass produced high performance street car products like that.

I changed the the exhaust system completely. I had the original factory system that came on the Special Wishes cars. It had a different kind of muffler in which the exhaust gases exited on the right side of the muffler out the right side of the valance and the wastegate exhaust exited out the left side of the valance. The heat exchangers were the Euro's, same as the HE's found on the later 930's. The muffler added was the B&B single out (left side).

Turbocharger was not changed. It had the standard KKK K-27 7006 found on the Special Wishes.

No dyno runs were made after the change, but the "seat-of-the-pants" told me that no big HP gains were made, but boost onset was very noticeable (and very welcome).

[DDDD]

Wow that is awesome.

No way in hell that B+Bs do better than that. I think they advertise +38-40 with the whole system, including headers and B+B muffler, and that is versus the restrictive american exhaust system.

[911st]

B&B's quotes 44hp improvement.



Euro 300.
Late US 282 ----- 18 less than euro
Early US 265hp -- 35 less than euro.

Euro muffler v Zork per Bruce Anderson adds 10hp.

Assuming a sport muffler might add 5hp, said 44hp would be 39 for just the headers.

This could equal about a 6 to 21hp to the B&B headers depending on if the base turbo was an early or late.

This is compared to Brian's quote of about 30hp for the fully equal length over the late US headers.

[turbobrat930]

Originally Posted by 911st

Brian,

Was looking for a B&B dyno chart for comparison and came across a note from 2007 that your were making 350whp at .75.

Seeing this I have to ask, what turbo and headers were you running then that made the same HP as the new headers?

Dyno Question

If I may... If you are talking about the part in his sig line where it says 350 WHP at .75 That is his updated signature. Any time you update your sig line, it will show up on all the posts you have made...including older ones...

[911st]

That makes sense, Thx.

[DDDD]

Originally Posted by 911st

B&B's quotes 44hp improvement.

Early US 265hp
late US 282
Euro 300.

Euro muffler v Zork per Bruce Anderson adds 10hp.

282+44 < 300+44. Good job Brian!

[DDDD]

This will put a dent in B+B sales amoung the enthusiast crowd...maybe not overnight...but how often does a 'better' mousetrap come along in the 930 community?

[copbait73]

Just got back home and checked the postings, Congratulations.

[911nut]

Another data point: YouTube - 964 Turbo Dyno Run

This, until recently, was Drew Hollingsworth's car (Rennlist member).
B&B headers, .9 bar, sport muffler (don't recall what brand) otherwise stock 3.3 L 965.
352 whp.

[boxermania]

Just looking at the dyno results and taking in consideration the 250 rpm offset, I conclude the following:

• Baseline dyno and the new headers dyno tests are two years apart.
• No A/F trace for the new tubes has been recorded.
• On paper it appears that the new headers flow better than the baseline.
• Evaluation of the torque trace, specifically the dip from ~3500 rpm to 4100 rpm, points to the possibility that enrichment needs to take place earlier to sustain the gains.
• The torque curves decay on a parallel path at the top end, don't see a fuel issue there.

Certainly the above doesn't diminish Brian's excellent workmanship and vested interest in the development of new ideas in support the community.

[RarlyL8]

I've done a bunch of dyno runs in the past 3 years. All show baseline right at 300HP and 315TQ. I used this particular baseline because it best represented that average.

AFRs were measured and on the graph but very faint. There is a fueling issue as I was never below 12.0:1 and leaned out to 12.5:1 @6000rpm. The stock WUR is at it's limit.
I will put on my adjustable WUR and tune the fuel before going back for another run. I wish to back this up as it is not a good graph. I took the liberty of smoothing the original data and that is my goal when the fuel tuning is complete.
Today was another beautiful day. I took the car out for a short ride in the mountains and man do I like the smooth torque off boost. You really can't see that on the graph. I can lumber at 1500rpm if I wish and pull off from a stop at 1000rpm, basically at idle. I do have a 915 but that has to help in a 930 4spd as well.

[Helmsy]

Just to get off topic what is the ideal AFR under full boost?

Oh and also I just noticed DDDD has 930 posts. I like that number....

[911st]

My two cents on AFR's:

Max turbo HP is near 13/1 but a 930 turbo will not live at that level.

A well designed turbo motor that is not pushing the limit to much or is water cooled and or EFI can usually run in the low 12/1's and make a lot of power.

However CIS is not accurate or balanced enough to do so under hight duty load like on the track.

More like the mid to low 11's for a 930. Especially at TQ peak where cylinder pressure is highest and risk of detonation at its peak. After HP peak I suspect we can run a little leaner like at 12/1.

Many current modern EFI turbos actually run in the 10's from the factory as a precaution. Extra fuel creates a cooling effect and reduces detonation potential.

Off boost something close to 13/1 makes more HP.

[RarlyL8]

Once I am finished tuning the fuel system I will be comfortable with 11.5:1 at max torque and 12:1 at redline. The entire CIS system will be flow and volume balanced.

It is important to note that I am running stock boost pressure and 93 octane fuel. Even at 12.5:1, with 60F ambient air and 180F oil temps the engine was safe for that run.

Once the fuel is re-tuned I will go back to the dyno to get an adjusted number. Lean mixture = HP so by richening it up I expect to drop a few ponies. This is one reason that individual results can vary. If you have a pig-rich worn out WUR running in the 9's then a bunch of power is on the table. It is also the reason I offer fuel tuning as a service when adding my upgraded parts. You need to at least verify the curve to get the most out of your performance parts.

[sjf911]

Congratulations! I know what I will be buying when my current headers give up the ghost.

[911st]

Originally Posted by RarlyL8

...The entire CIS system will be flow and volume balanced...

The more power we make the more important this goal becomes.

The equal length headers seem to be an an important part of this. Equalize the exhaust side and it helps to equalize the intake side. This helps by better equalizing the residual exhaust pressure that stays in each cylinder when the exhaust valve closes.

However, a balanced head, injectors, and exhaust is not enough to make for a balanced system on a 930.

Bench tests have shown the air flow per cylinder is far from balanced with the stock 930 intake manifold.

We can Extrude Honed the intake manifold to get it pretty well balanced. However the manifold has to be opened up significantly to achieve this. With this the injector blocks then have to each be hand tapered to transition from the enlarged intake manifold to the stock heads as each manifold runner will be a different size.

Say we get our systems truly in ballance. We still have a problem. Our systems do not adjust or compensate well for changes in environmental conditions.

With EFI one might run 12.2/1 AFR and a bunch of timing advance and make a bunch of HP.

However, it also has built in features like using oil/intake air temps, measuring air density instead of air volume, and monitoring knock sensing to then pull timing back, increase the AFR's, or even pull back boost to protect the motor.

The 91-94 C2 CIS Turbos do have some added protection and can adjust timing about 6 deg from cold to hot temps and its WUR has some compensation for altitude changes. None of the 76-89 turbos do.

So yes we can make biger HP numbers on a dyno with aggressive AFR's and timing values. We can probably even get away with settings that make big power on the dyno and or on the street in most situitions.

However, if we set the motor up on a cool day and we try to run this at the track on a hot after noon; try to do our best 1/4 miler away from a stop light after sitting with our AC on; or just get a poor tank of gas-- we may get in big trouble quickly.

Still, the more balanced we are the more insurance we have as we run closer to peak power making AFR and ignition settings.

Brian's new headers with an Extrude Honed intake might be a nice combination to think about as to making more HP and running a safer CIS motor.

[RarlyL8]

However, if we set the motor up on a cool day and we try to run this at the track on a hot after noon; try to do our best 1/4 miler away from a stop light after sitting with our AC on; or just get a poor tank of gas-- we may get in big trouble quickly.

Yes which is why you must know your engine well if tuning yourself. The build/tune sheets I use for adjustable WUR's include consideration for track use and environmental conditions. You always add in a tweek for safety/longevity.
I am planning to do some turbo testing this spring which will require fuel head adjustments. It becomes even more critical to balance the distribution of fuel as HP, heat and boost increase. I'll be going to 1.0bar at 7000rpm which is much less forgiving than the 0.75bar at 6000rpm we did for initial testing of the headers.

[911st]

I screwed that one up.

Correction -- if AFR's are set on a hot day they can go lean on a cool day where the air is denser. CIS measures air volume, not so much density and dose not compensate.

Still, we need to be aware CIS can not compensate for environmental variances and is not as accurate as EFI so we should run a little fat compared to other turbo's at the expense of some peak HP.


Also interesting is with more boost CIS delivers less fuel. EFI uses the fuel pressure regulator to increase injector delivery pressure when manifold pressure increases as compensation. CIS dose not have any compensating provision for this. Thus, the higher the boost the lower the gross amount of fuel that can be delivered.


PS, 7000rpm is not safe with stock rods on a 3.2/3.3.