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Image depicts fabricated 1/4" steel.plate which replaces the ACIS butterfly valve assembly in the upper intake plenum during extrude honing. Notice the two countersunk holes that provide clearance of the registration pins (for butterfly valve assembly port centerinng) and allow flush mounting over ports. You can see perfect circular burnishing of plate where extrude honing material containment occured as it traveled entire length of intake runners Upper intake manifold plenum.
Block off plate covers the 8 inline butterfly valve ports to direct extrude hone material through entire runner length...without plate extrude honing material would bypass low speed RPM runners and shortcut through these high RPM runners. Another image of lower intake plenum taken at Extrude Hone facilities in Irwin, PA.
Some observation on the ACIS high RPM butterfly valve assembly ports;
This trumpet-shape area would respond well to simple radiusing of the sharp edge..(but above the port area where the plate closes)
This would allow smooth and even entry of air at high velocities into the high RPM intake tract with the flow stream adhering to the walls known as laminar (or smooth) The present configuration generates a fair amount of turbulence...especially at it's 4,000 RPM opening
I just want to see the numbers that compare the stock vs all this work.
Extrude honed intake installed today.... Dyno testing scheduled for June 19th.
I can report the idle is appreciably smoother because laminar flow is much improved, the intake runners are now more uniform in size..probably within 1-2%, of each other , acceleration is much more athletic due to increased velocity coupled with cooler intake charge and the traction control kicks in when applying full throttle while cruising at 40 MPH.
This feels like at least 20 H.P....it ceratainly is not 10...
According to Vizard, the amount of radius at an entry to avoid the "vena contracta" effect you show in the illustration is surprisingly small. The magic number (at least for std air density) is 3/8" radius. 1/2" show only a very small gain, but 1/4" is considerably worse.
IIRC the best effects of an Extrude-Hone are when:
1. the interior surface is rough "as-cast"
2. there are surface interruptions such as casting separation lines
However, the improvement isn't that great (and not as cost-effective) because moving air has mass and follows the outer wall radius, while the slurry's path is almost centered in the passage's diameter, thus removing material from surfaces where air motion is almost absent. I think it also tends to equalize cross-sectional area and removes proportionately more material from smaller passages.
Yes, it's still better than not doing it.
As cast, the stock.manifold has relatively pronounced casting seams in all upper and lower intake runners...about 4 hours work with Dremel tool remedied this before sending to Extrude Hone.
The Dremel tool effortlessly and uniformly removed a majority of these seams.
Several of the runners required more attention.
Casting flash and roughness was also lightly removed in intake runners with the Dremel tool where practical...and as ypu see, extrude honing took care of the rest .
I just want to see the numbers that compare the stock vs all this work.
EXTRUDE HONE DYNO RESULTS
Attached are before and after dyno results for Extrude Honing of 1999 LS400 intake manifold.
As discussed, off the line acceleration is more athletic and mid-range is much improved.
Mid-range acceleration is off the hook fast.
Dyno testing indicates max torque of 257.43 compared to earlier 230.36 and max rear wheel horsepower of 241.60 vs. 232.60.
More significant is uder the curve horsepower and torque differential;
Horsepower
before : 191.84@4,382 RPM,
after: 212.95@4,382 RPM
Torque
before: 229.93@4,382 RPM
after 255.24@4,382 RPM THANKS TO MCGRATH LEXUS CHICAGO AND EXTRUDE HONE IN IRWIN PENNSYLVANIA FOR SUPPORTING THIS PROGRAM!
As the high RPM runners are much shorter than low RPM runners, then this would in part explain the smaller spread in torque in horsepower improvements using the extrude hone process.
I did not smooth the inlet of high RPM butterfly valve trumpets to improve laminar flow...Perhaps one or two horsepower would obtain here.
Low and mid RPM seat of the pants results are phenominal...feels like I am pulling out of pits in an Indy car.
If anyone has questions, Rick Miller at Extrude Hone in Irwin,, PA is your contact.
Javier at McGrath Lexus has available a list of necessary parts, gaskets , hoses, clips, fasteners.
What were air temp and density on both days of dyno testing?
Are the peak hp/tq RPM numbers a typo? It's suspect that 2 runs would produce exactly the same peak RPM, and hp/tq peaks are usually at (slightly) different RPM.
Did the dealership and EH monetarily sponsor this test?
If we presume the numbers are true, and the temperature o both days of testing are exactly the same, i believe the result is mostly as expected. a 4% gain is within the margin of error for most chassis dynos, and as you only posted 1 run for after we have no measure for consistency. The TQ improvement seems signiicant but without more data it's hard to ay.
Given the cost of an extrude hone ($6-900 USD for similar manifolds), as well as the downtime, there are way better ways to make power for less money.
What were air temp and density on both days of dyno testing?
Are the peak hp/tq RPM numbers a typo? It's suspect that 2 runs would produce exactly the same peak RPM, and hp/tq peaks are usually at (slightly) different RPM.
Did the dealership and EH monetarily sponsor this test?
If we presume the numbers are true, and the temperature o both days of testing are exactly the same, i believe the result is mostly as expected. a 4% gain is within the margin of error for most chassis dynos, and as you only posted 1 run for after we have no measure for consistency. The TQ improvement seems signiicant but without more data it's hard to ay.
Given the cost of an extrude hone ($6-900 USD for similar manifolds), as well as the downtime, there are way better ways to make power for less money.
When I initially posted two "before" dyno runs, despite the fact they were almost exactly the same, the question arose whether they were "before" and "after (extrude honing).
In this instance I have available "before" and "after" dyno runs, so as to avoid that same question, as here, I had the operator post before and after on the same sheet for ease of comparison...
The second dyno run is not shown to avoid that question.
Indoor test facility, and temperatures were very similar...but think humidity was 32% and 36%.
McGrath facilitated the dyno testing.
Their parts department patiently compiled 3 pages of parts that I ordered for the project..I replaced all water and vacuum hoses, gaskets, fasteners (every fastener removed is new).
It is not "hard to say" on these results...
I reported earlier that the car accelerated not just a little faster, but significantly faster.
Idle quality improved, throttle response improved..admittedly the gas pedal is more touchy.
At full throttle from lower/ mid RPM's the power just seems to increase exponentially....
The lower RPM dyno results reduce to writing what I already knew.
Due to the manifold design, greater improvements seem to occur at low through mid-RPM range and then taper off a bit when ACIS throttle plates open to high RPM intake runners.
Recall that the extrude hone process does not port the intake runners in the traditional sense, but removes casting flash and seams, while polishing resulting in increased velocity and, equalizing flow to each cylinder...so the shorter the intake runner....here when the low RPM long runners become high RPM short runners by operation of opening the ACIS butterfly valve gang assembly..then in the case of this manifold design, HP. and torque figures do not show as much of a spread over stock.
If I wanted to honk out the runners then my high RPM figures would have been much greater than 10 HP at 6,000 RPM (My engine hardly spends any time at 6,000 RPM, but 4,000 to 5,000 RPM is prone to happen.)
This tells us that Toyota did a credible design job at 6,000 RPM but left about 20 HP and 25 ft.pounds of torque at lower RPM on the table.
The goal here was never to compromise ANY low end torque, but increase usable power across the curve.
I did not port match the intake to the heads....that would be worth a few HP
I felt presenting extrude honing process solely on its merits was the way to go.
I do not have the necessary resources to sort out and measure where additional power could be achieved, but on the 4,000-6,000 RPM range believe smoothing out the harsh transition on the ACIS butterfly valve inlet trumpets would produce improved laminar flow.(=HP)
I chose not to introduce variables nto this test, but will have my butterfly valve gang assembly sent out to remove the offending inlet transitions at some future date.
Meanwhile, I am contemplating extrude honing intake and exhaust ports on the cylinder heads...
The intakes look really good..almost vertical in realation to valve opening, but extrude honing exhaust ports would decrease dissipation of exhaust heat into the head..(rough casting area = increased heat absorsion ) increased velocity...and .perhaps allowing the ECU to advance the timing futher if the knock sensor is not alerting the engine to retard.
Probably would also employ other thermsl management techniques such as thermal coating of exhaust runners, cylinder head combustion face and valve faces..
I just wanted to thank you for the effort and time in compiling this. Having used extrude honing in the past on pushrod V8s, I've always wondered what the result would be in the Lexus V8. Being familiar with Ford DOHC V8s, I've seen 10+ percent increase in flow on their intakes after extrude honing. Because of those results, I've always had an inkling that even relatively minor improvements in intake and head breathing would yield nice results in the UZ. This engine loves to flow and your results confirm what I've always suspected. It seems after all these years despite many positive results people still doubt the effectiveness of this process. The improved surface finish increases intake velocity and that's what we're seeing here. The casting process leaves a dimpled surface finish (think of the dimples on a golf ball). By removing these surface imperfections you increase velocity and flow. And on a free breathing engine the results are usually positive.
That's again...This was a great project and I really appreciate it.
Curious about the cost? It's been a few years since I've done it. I'm guessing around $800?
I just wanted to thank you for the effort and time in compiling this. Having used extrude honing in the past on pushrod V8s, I've always wondered what the result would be in the Lexus V8. Being familiar with Ford DOHC V8s, I've seen 10+ percent increase in flow on their intakes after extrude honing. Because of those results, I've always had an inkling that even relatively minor improvements in intake and head breathing would yield nice results in the UZ. This engine loves to flow and your results confirm what I've always suspected. It seems after all these years despite many positive results people still doubt the effectiveness of this process. The improved surface finish increases intake velocity and that's what we're seeing here. The casting process leaves a dimpled surface finish (think of the dimples on a golf ball). By removing these surface imperfections you increase velocity and flow. And on a free breathing engine the results are usually positive.
That's again...This was a great project and I really appreciate it.
Curious about the cost? It's been a few years since I've done it. I'm guessing around $800?
The results were greater than expected
Rick Miller at Extrude Hone, Irwin Pennsylvania quoted $610 for ClubLexus members.
They have necessarytooling and fixturing for this intake.
amazing numbers, more than I thought possible. I never knew the newer VVTI intakes had secondary butterflies! great work by the pros and your efforts in showing your results.
do you think the ECM will eventually compensate for the better flow with more fuel usage?
amazing numbers, more than I thought possible. I never knew the newer VVTI intakes had secondary butterflies! great work by the pros and your efforts in showing your results.
do you think the ECM will eventually compensate for the better flow with more fuel usage?
The extrude hone process removes casting flash, casting seams and overall roughness while polishing the intake runners wwhich improves laminar flow, and velocity and allows the engine to breath easier across the RPM range.
Due to smooth runners, less heat is imparted into the intake stream, so besides ireduced thermal turbulence, the intake charge is cooler.....perhaps this is allowing the ECU to advance timing...
It also improve uniformity of flow between runners...the idle was already smooth....now it feels more so.
It is not porting in the traditional sense where lots of material is removed and power might be lost at low-mid range for some higher peak RPM..
Wasn't interested in sacrificing any low RPM power or efficiency.
Extrude honing should improve overall efficiency, so engine should use less fuel with reduced emissions at part throttle for low and mid RPM.
I think the ECU can accommodate this...
On information the stock ECU will handle plus or minus 10-20% (depending upon source)
However, at full throttle with improved flow the engine probably requires more fuel.
I think the ECU is capable because the dyno is showing increased power ourput...and because I feel.a dramatic difference in throttle response and acceleration.
Not suggesting that the ECU has not already exceeded its ability to compensate at higher RPM.
That could be occurring already at 6,000 RPM, but I do not think that is the case.
Perhaps one way to find out is to extrude hone the cylinder heads and dyno.at redline.
I also think that slight modification of the very sharp welded OEM exhaust pipe transition just past the catalytic converter flange on exhaust pipe will yield torque and H.P. improvements across the RPM range.would compliment the extrude honed intake.
05-23-17, 08:25 PM
