Exhaust collector configuration. 2

[mburgess]

Has anybody had experience with designing headers with primary & secondary collectors ie. 4-2-1 layout for inline 4 cyl engines as opposed to 4-1 collectors. I have been making some headers with mixed results for some time now. The designs have been based on what I have seen at racetracks and in magazines. However I still really don't know why one design works & another doesn't. The fabrication side of it is the easy part. Are there any relatively inexpensive modelling packages available that anyone has had some success with.
Regards,
MB

 

[MaxRaceSoftware]

if you have a really great exhaust port
and Ex/In Ratio, cam specs, engine combination, etc
along with correct pipe diameters/lengths
along with correct intake port velocity

the 4-2-1 will not make a substantial difference


if you have an exhaust port that is not so great, or bad E/I Ratio, incorrect intake port velocity, etc
there is a much greater chance of gaining with 4-2-1 system

its something you have to tryout on the Dyno and especially at the Track, as engine will accelerate
different rates on Track than Dyno



Larry Meaux (maxracesoftware@yahoo.com)
Meaux Racing Heads - MaxRace Software
ET_Analyst for DragRacers
Support Israel - Genesis 12:3

 

[mburgess]

Thanks Larry,
Thats pretty much where I'm at. Fortunately I have a friendly dyno operator. Just trying to narrow down the options before heading there.
MB

 

[MaxRaceSoftware]

mburgess ,

if you post all the "Inputs" required in the Link below

http://www.maxracesoftware.com/prod05.htm

i'll run a computer simulation ...then you can see how close it came when you get on the Dyno



Larry Meaux (maxracesoftware@yahoo.com)
Meaux Racing Heads - MaxRace Software
ET_Analyst for DragRacers
Support Israel - Genesis 12:3

 

[mburgess]

Larry,
I would be interested in results, info as follows,

Bore: 2.264
Stroke: 1.535
Rod: 3.485
Cyl: 4
Comp: 13.00

Intake,
Valves/Cyl: 2
Valve Dia: 0.866
Stem Dia: 0.157
Max Lift: 0.298 (valve lift after rocker)
Duration @0.05: 216
Deg Cent: 110

Exhaust,
Valves/Cyl: 2
Valve Dia: 0.748
Stem Dia: 0.157
Max Lift: 0.292 (valve lift after rocker)
Duration @ 0.05: 219
Deg Cent: 108

LSA = 142 deg, does this sound right, I'm only use to twin cam heads.

Thanks in advance,
Michal Burgess

 

[mburgess]

Also was duration meant to be at 0.05 or 0.005
is req at 0.005,
Intake = 345 deg
Exhaust = 338 deg
Regards,
MB

 

[MaxRaceSoftware]

yes, duration was at .050" (popular method)

you forgot to state the RPM point you want to make Peak HP at ?? ....thats the single most important "Input" in this program..needs to be within 100 rpm accuracy

i need a good accurate guesstimate of Peak HP RPM ?

if you are going to be on the Dyno for more than 1 day or post Dyno "peak HP RPM numbers" after a few tests,
then i can do a quick simulation ..it will give you something to look at and compare..you might be able to get more out of the engine ?




Larry Meaux (maxracesoftware@yahoo.com)
Meaux Racing Heads - MaxRace Software
ET_Analyst for DragRacers
Support Israel - Genesis 12:3

 

[mburgess]

Sorry, bit late last night,
Looking for peak hp around 13300 rpm, limiter at 14500, can be programmed to 15000 for a bit more overrev. Rev range used from as low as 8000rpm however 10000 to 14000 most commonly used.
I can post previous dyno runs.
Thanks,
MB

 

[MaxRaceSoftware]

MB , here is a Link with results

thats the smallest engine i've ever tried to model
maybe we will both learn something ??

http://www.maxracesoftware.com/Pipe_1.jpg

for 13,300 RPM

MB ... whats this engine going in and what kind and Brand name ??


Larry Meaux (maxracesoftware@yahoo.com)
Meaux Racing Heads - MaxRace Software
ET_Analyst for DragRacers
Support Israel - Genesis 12:3

 

[mburgess]

Thanks Larry,
Engine is a Kawasaki ZXR400, 400cc inline 4 motorcycle. There is a class here in Aus for them. Race against Honda CBR400 (inline 4) VFR400 (v4) RVF400 (V4) Yamaha FZR400 (inline 4). Not huge amounts of hp so you have to really concentrate on cornering. However a good rider can really give someone on a 1000cc machine a bit of a shock. They can be rev'd to 16000rpm however aftermaket valve springs are not available so not real keen to do this. BTW the jap manufacturers also make 250cc inline 4's that rev to 22000rpm. These have a bit of a habit of burning holes in pistons when run that hard for extended periods. Ridden by learners so not alot of attention paid to fuelling. So far have got the machine from 56hp at the wheel to 68hp with a better spread of power.
Regards,
MB

 

[MaxRaceSoftware]

What did the engine want as far as ;
Primary pipe OD and Length
Collector OD and Lengths ?



Larry Meaux (maxracesoftware@yahoo.com)
Meaux Racing Heads - MaxRace Software
ET_Analyst for DragRacers
Support Israel - Genesis 12:3

 

[mburgess]

Exhausts that have been tested so far. These are header pipe lengths. Exhaust port is 50mm (2") from exhaust valve to gasket face.
#1 Standard 4-2-1 system. 1 1/8" headers 600mm (23.6") into 1 1/2" secondary 250mm (10") into 2" tailpipe 560mm (22") & 450mm (17.7") reversing flow muffler. Most restricive. Power peaking at 12000rpm 56hp.
#2 As above with straight through perforated core muffler. 59hp at 13000rpm.
#3 4-2-1 system. 1 1/4" headers 600mm (23.6") into 1 1/2" secondary 250mm (10") into 1 3/4" tailpipe tapering to 2" 550mm (21.6") & 450mm (17.7") straigh through 2" muffler.
64hp at 13500rpm. More power from 5000rpm to 14500rpm. Significant increase from 8000rpm onwards.
#4 4-1 system. 1 1/4" headers 600mm (23.6") into a 2" tailpipe 680mm (26.8") & 450mm (17.7") straight through muffler. 63hp at 14000rpm however was lower from 9000rpm to 11000rpm.
#5 4-1 system. 690mm (27.2") header tapering from 1 1/4" to 1 3/8" after 150mm into 1 5/8" tailpipe tapering to 2" 660mm (26") long & 450mm (17.7") straight through muffler. Very similar results to #3 however power curve wasn't as smooth with less throttle response. Jetting was different as well. 1 3/8" headers was based on sizing of the honda's seem to run well with them.
#6 4-2-1 system. 1 1/4" headers 600mm (23.6") into 1 1/2" secondary 150mm (5.9") into 1 3/4" tailpipe tapering to 2" 550mm (21.6") & 450mm (17.7") straigh through 2" muffler.
64hp at 13500rpm. Very similar to #2 however power stayed on more after 13500rpm.
Also have found more power by experimenting with length & dia of entry of velocity stack's.
Of particular not with this engine is that it had large exhaust ports, approx 1 3/8" in dia with standard header being 1 1/8". Seeing that best results obtained with 1 1/4" header I am now in the process of preparing a head with welded up exhaust ports to approx 1 1/8" dia to give a slight reversion barrier for a 1 1/4" header. Wanted to experiment with a taper in muffler to give a megaphone effect try & make 1 3/8" tapered header work. Maybe too big.
I also noticed that you did run at 2.00am in morning. Much appreciated. Just putting new head together now to experiment with.
I thhink I will buy a copy of your prog to experiment with. I am assuming you can multiply out tuned lengths for better packaging. I also foun some books on SAE website that deal with wave theory in exhausts an manifolds that I have ordered.
Regards,
Michael Burgess

 

[MaxRaceSoftware]

Many Thanks for sharing your Dyno data

the smallest engine i usually model is the Jr. Dragster 14 to 15 cid 2-valve gasoline or methanol

yours was the smallest 4-Valve engine i've had good enough data to model

i'm calculating approx

1 1/8 dia Primary Pipe(Largest) and no longer than 28.6 inches for best power curve

1 7/8 dia Secondary Pipe (with exh pipe/muffler length)
and no longer than 41 inches for best power curve

Total Exh System Length to atmosphere = 69.6 inches

-----------------------------------------------------
it looks like your best results are with ;
1 1/4 dia Primary pipe and 23.6 inches

and about close to 1 7/8 dia as an average Secondary Pipe
around 45.2 to 49.7 inches

Total Exh System Length to atmosphere =
between 68.8" to 73.3


i'm not doing good enough in accounting for the excellent
Low-Lift 4-valve flow -vs- 2-Valve..along with the siamesed
2 valve going into one larger cross-sectional area on the exhaust and intake sides of 4-Valve heads -vs- 2-Valve heads

but at least i wasn't a mile off




Larry Meaux (maxracesoftware@yahoo.com)
Meaux Racing Heads - MaxRace Software
ET_Analyst for DragRacers
Support Israel - Genesis 12:3

 

[MaxRaceSoftware]

On the Intake side

i calculate 7.4 " as best Mid-Port Intake Length

from seat angle-to-runner entry in plenum


Mid-Port is also the center of the port
the imaginary port length along the center of the port



Larry Meaux (maxracesoftware@yahoo.com)
Meaux Racing Heads - MaxRace Software
ET_Analyst for DragRacers
Support Israel - Genesis 12:3

 

[mburgess]

Larry,
I thought that you cal's were pretty close. If you added primary to secondary lengths (sys #6, 23.6"+5.9"=29.5") is very close to your calculation of 28.6". For the intake I am currently running around 220 - 240mm (8.7" - 9.4"). These are derived totaly by experimentation. I had a gut feeling that shorter again may be the go, so you might be on the money. There seems to be a fasion in the latest exhaust design (in Grand Prix motorcycles)to taper from a small dia at the exhaust port to a relatively large dia header with a megaphone style muffler. Strange how history repeats, very similar to exhaust design on bikes in the 60's. I think that I will try your calcs, will be a couple of weeks before I am back on the dyno. From experiments I have found so may variables. also found that Airbox volume had a significant effect on midrange.
Regards,
MB

 

[mburgess]

Also header dia's seemed spot on. 1.140" header = 29.0 mm
1 1/4" 18 guage tube ID = 31.75 - (2 * 1.2) = 29.35 mm
Tailpipe of 1.894" = 48.1 mm
2" 18 guage tube ID = 50.8 - (2 * 1.2) = 48.4 mm .
What does the H pipe & X pipe refer to?
regards,
MB

 

[Windsor377]

I don't know. You better keep an eye on what the MaxRaceSoftware guy has to say!

Larry and MB, do you mind if I ask another header related question here? The 4 2 1 configuration has me pondering the "un-equal" length headers I need to run in SSO combinations.

 

[MaxRaceSoftware]

Larry and MB, do you mind if I ask another header related question here? The 4 2 1 configuration has me pondering the "un-equal" length headers I need to run in SSO combinations.
-------------------------------------------------

Henry, the "un-equal" primary pipes make my Collector calculations somewhat wrong . It still gets the total exhaust system lengths correct, but if you test the engine on the dyno with just the collector (without the rest of exhaust pipe/muffler/tail-pipe lengths), the unequal primaries makes the collector too sensitive to length
and responds too much to many lengths that wouldn't ordinarily work, and you can never make the engine make its max torque its capable of, but it can sometimes widen the torque/power curve with unequal lengths.


Larry Meaux (maxracesoftware@yahoo.com)
Meaux Racing Heads - MaxRace Software
ET_Analyst for DragRacers
Support Israel - Genesis 12:3

 

[Windsor377]

Thanks Larry. I didn't think there was an easy way out. I'll ask one more question then leave MBs thread alone.

Would it make any sense at all to try to build step headers with the "un-equal" length primaries. If so, would it make more sense to tune each step of each pipe with regards it's length and implied optimum rpm, or try to map the lengths to the overall power curve of the engine?

 

[mburgess]

Windsor377, ask away, not just our thread, I put the question out for all idea's. Can I ask what is SSO?
regards,
MB