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The extrude hone project also posted before and after dyno results...unfortunately torque and H.P. increases do not agree with everyone's thinking.
can we agree that the stock new hp is 290?
your dyno run got 241.6 hp, i'll give you the complete benefit of the doubt and factor in a 20% drivetrain loss (almost certainly too much but lets roll with it), 241.6 * 1.2 = 289.92 crank hp
your dyno run got 241.6 hp, i'll give you the complete benefit of the doubt and factor in a 20% drivetrain loss (almost certainly too much but lets roll with it), 241.6 * 1.2 = 289.92 crank hp
idk how 289.92 is a gain from 290
Before and after chassis dyno (rear wheel) results
The Corvette has an OEM ECU...and before/after dyno results suggest increased power from a simple thermal barrier
The extrude hone project also posted before and after dyno results...unfortunately torque and H.P. increases do not agree with everyone's thinking.
Feel free to develop and post particulars of your reflash project.
The corvette is again using the fuel margin unless they tuned it, if they tuned it a LS based car will gain 15% from a remap alone plus GM cars in general have far less advanced emissions targets vs Lexus vehicles allowing more wiggle room even on the stock program.
As far as your chart goes you should have done the runs with full heat saturation for each and averaged them, as it stands your car was making below rated power when stock. I will bet if you redo the run after a hour drive you will not see any more power than the original figure.
I don't really have to update on anything since what I intend to do is a known upgrade and guaranteed to give at least 10% more wheel HP. I do plan to do a stock 1/4 mile run and compare the changes in that metric though but I'm not going to waste money on dyno time for a LS
You are factory speced at 6.3 0-60 and 14.8 1/4@97mph and I am curious what you are getting vs these numbers. At least do a 0-60 test to see if you gain anything or if you have room run up to 97 and see how many seconds that takes vs 14.8 to see if anything is improved at all.
If you just would tune the thing already you would see real gains. What you are doing is like what I did to another one of my cars but not tuning it and expecting more power, you can't double the output using a stock map even if all the parts support a 245 up to 425 increase. It's just not going to work and I hate to see the effort wasted.
The engine valley contributes significantly to heat soak into Aluminum intake manifold.
This post presents application of DEI thermal insulating material beneath the intake manifold as a heat barrier to significantly decrease intake temperature.
After 70 MPH highway driving, thermal readings range berween 91 - 104 degrees Fahrenheit
Prior to application of thermal barrier, top of intake manifold was way too hot to touch.
Welcome forum members to post "Before" temperature readings.
Ceramic coating of exhaust manifolds and exhaust manifold heats shields may be a contributing factor. See;
The corvette is again using the fuel margin unless they tuned it, if they tuned it a LS based car will gain 15% from a remap alone plus GM cars in general have far less advanced emissions targets vs Lexus vehicles allowing more wiggle room even on the stock program.
As far as your chart goes you should have done the runs with full heat saturation for each and averaged them, as it stands your car was making below rated power when stock. I will bet if you redo the run after a hour drive you will not see any more power than the original figure.
I don't really have to update on anything since what I intend to do is a known upgrade and guaranteed to give at least 10% more wheel HP. I do plan to do a stock 1/4 mile run and compare the changes in that metric though but I'm not going to waste money on dyno time for a LS
In response to:
"As far as your chart goes you should have done the runs with full heat saturation for each and averaged them, as it stands your car was making below rated power when stock. I will bet if you redo the run after a hour drive you will not see any more power than the original figure."
The Extrude Hone post contains that an extra intake manifold was acquired for extrude honing.
So the before dyno readings are with the stock intake manifold, and the after with extrude honing, albeit different days.
The dyno facility is booked solid so works on scheduled appointments.
In both dyno runs, a 45 minute highway drive, and upon arrival, you are in the dyno bay and running.
There were two before dyno runs and the figures were identical.....so not necessary to average.
Am satisfied with the controls in place.
Perhaps you conduct your own extrude hone program and post results.
Located this informative article presenting benefits of using thermal isolating gaskets between cylinder head and intake manifold....AND some before/after data.
While Toyota/Lexus incorporated a similar concept starting 1998 LS400, so it appears 1990-1997 LS400 did not use these improved gaskets...(curious if 1998-2000 LS400 intake gaskets will work on 1990-1997??)
1998-2000 LS400, 2001-2006 LS430 insulating intake manifold gasket Insulating material sandwiched between two metallic compression style gaskets. Metallic top and bottom gaskets held in place with rivets. Image depicting the crush or compression feature of OEM intake gasket. These are used, so the raised portions are not as prominent as new...why reuse is not recommended. Also (low) torque spec to avoid cracking the inner gasket...torque wrench is a necessity.
The author has manufactured gaskets, but would sandwich the thermal isolating material between two thin metal gaskets as Toyota did.
"Why it Works
While many avenues exist for boosting the power output of an engine, most approaches focus on ways to increase the volumetric efficiency of the system. Ported heads, larger diameter exhausts, headers, and bigger throttle bodies serve to decrease the resistance to airflow through the engine. The modification shown here, however, does not increase the volume of air flowing through an engine, but rather increases its mass flow.
Cold air is more dense than hot air and takes up less space. So if your engine can ingest cooler air, more air can be mixed with more fuel, which gives more power. An additional benefit is that cooler air has a higher resistance to knock, allowing more ignition timing advance - or boost in supercharged applications. Either way, they both equal more power! This is the theory behind cold air intakes, ice on the manifold, and intercoolers.
The intake air in EFI engines is drawn through the airflow meter and throttle body, and then into an alloy intake manifold. During its residence in the intake manifold casting, the air charge picks up unwanted heat from the manifold, increasing its volume and lowering the resistance of the engine to knock. One of the possibilities for reducing the intake air temperature is to install a cold air intake. However, another possibility is to reduce the heat conduction from the hot engine to the intake manifold by thermally separating the two. By replacing the steel intake manifold gaskets with an insulating spacer, heat conduction to the manifold can be greatly reduced. The best material for the spacers has a low thermal conductivity, high compressive strength, is able to withstand up to 300 degrees F (~150 degrees C), and is affordable. Phenolics, with excellent insulating properties, high stiffness, and the ability to withstand 500+ degrees F (260 degrees C), are commonly chosen for similar applications. Additionally, the coefficient of thermal expansion of a phenolic is similar to that of aluminium, which helps to reduce sealing problems in this particular use.
When compared to the 0.025 inch steel gasket it replaces, a quarter inch thick phenolic insulator will conduct 200-1000 times less heat! Although the insulation benefits increase with thickness, ¼ inch (6.4mm) sheet was chosen because this is the thickest that can generally be used with stock mounting studs and bolts.
Finding 'Em
Several companies, including Ford Motorsport, offer insulators for 5.0L Mustang owners as well as for carburetted applications - just look through a Summit Racing catalog!. The most common thicknesses are 3/8 -1 inch and prices are generally in the US$50-$60 range. However, as is usually the case when it comes to performance mods beyond intakes and exhausts, nothing was available for my Mazda V6. This is one reason I decided to look into the possibility of designing and fabricating some insulating spacers for myself (and also anyone else who was interested). Building upon a previous spacer design, I was able to create a CAD drawing of the item and got several quotes for making a production run of approximately 50 sets potentially utilising everything from standard milling and machining to abrasive water jet cutting. I found a competent local company and after working through some initial fabrication problems, I was able to get sets made that were of very high quality. Too bad you can't see them after they're installed!
I now have insulators to suit the Mazda 1.8L-2.0L-2.5L K Series V-6 engines, with more than 75 sets so far being sold for this engine. I am currently considering expanding the coverage to include some other vehicles in the sport compact segment (Honda, Nissan, Toyota, etc) - please contact me for more details.
Installation
Installation of a set of insulators should take approximately 3 hours and can be accomplished by the average home mechanic with common tools. I did the install outside in my driveway and had no major problems. I was initially concerned about the amount of jury rigging that might be required, but was pleasantly surprised that for the most part, it is a bolt-on job.
Results!
Having seen the unsubstantiated claims of numerous bolt on parts suppliers who say that their product will give you "up to XXXX extra horsepower!", I was determined to be able to show data that the insulators indeed worked as claimed, or didn't work, if that was the case. I have used three different methods of testing the effectiveness of this mod - dyno numbers, temperature data, and quarter mile drag strip results.
Dyno Numbers
I wish I could say that I have a chassis-dynamometer in my garage, but such is not the case. I do have a G-Tech Pro, but I have not been overly impressed with its accuracy or repeatability. So how did I do the testing? I heard about a computer program called The Home Dyno while I was lurking on a Honda/Acura list (gotta know what the competition is up to!). In a nutshell, you make a recording of your spark plug pulses taken from an inductive pick-up on one of your plug wires during a 1500-7500 rpm acceleration run. You then download the pulses into your PC and The Home Dyno is able to construct a power plot using the relative time differences between the pulses. Being a mechanical engineer by day, I was somewhat doubtful about the method, but after giving it some thought, I decided to purchase the program and give it a shot. After using it for the past several months, I have been absolutely amazed by The Home Dyno's accuracy and repeatability. The program outputs a graph as well as a load of data that can be dumped into Excel or other spreadsheets and then manipulated. It also corrects for altitude, weather conditions, driveline loss and aerodynamic drag. In addition to the graphical output, the HomeDyno also outputs several pages of numerical data. It really is neat little program and I highly recommend it, especially for those all wheel drive vehicles that cannot so easily be dyno'd.
During my dyno runs, I was always careful to pay attention to vehicle weight (there is a scale near my home), weather conditions, and I did a run in each direction then averaged the results to take care of any road grade and wind discrepancies. My runs before and after the installation of the phenolic spacers were done on the same day with all variables as close as I could manage, ie warmed up engine, same stretch of road, etc. According to the plots, I gained approximately 7hp and 11 ft-lbs of torque using the spacers over the majority of the power curve. I can make no claims as to the accuracy of these results, but they do seem reasonable.
Manifold Temperature Data
The basic function of the insulators is to reduce intake manifold temperatures, so what better way to test than to record and compare temp data before and after the install? I took the temperature readings from the front centre intake runner using a professional quality CPS T200 temperature sensor with a time constant of the order of 5 seconds. The sensor was mounted on the front middle intake runner for all tests and the vehicle was driven as close to 60 mph (~100 km/h) as traffic would allow. After the driving test, the engine was allowed to idle for a sufficient time to show the maximum temperature.
The data is shown as a temperature change above ambient. As you can see, the temperature of the intake manifold reached a steady state of approximately 30 degrees F (17 degrees C) lower - 40 degrees F versus 70 degrees F - with the insulators than without during 60 mph cruising. During the idle test (the higher temps at the right end of the graph), the non-insulated engine was 52 degrees F (29 degrees C) hotter and still climbing when the test was aborted. A non-quantitative comment: I can place my hand on the intake after a drive with the insulators installed, whereas I would have burned myself previously!
Quarter Mile Drag Results
My best time prior to the spacer install was a 15.360 at 88.469 mph with a 60 foot time of 2.209 seconds. This was during last year's season where I ran 29 races at Thompson Drag Raceway in north-eastern Ohio. The first time back at the track this year I ran a best of 15.262 at 89.315 mph with a 60 foot time of 2.282 seconds and with the insulators as the only additional modification. The temperature during both races was about 55 degrees F (13 degrees C). To summarize, I was ~0.1 seconds quicker and ~1 mph faster, all with a .073 second slower launch.
Summary
Having seen many people shell out hundreds of dollars for performance mods of dubious value, I wanted as much data as possible to show that this intake manifold insulator thing really worked. I was able to show that:
The intake ran 30 degrees F (17 degrees C) cooler at cruise and at least 50 degrees F (28 degrees C) cooler at idle;
According to my dyno plots, I gained up to 7 horsepower and 11 ft-lbs of torque over the major portion of the power curve.
My best time at the track was ~0.1 seconds quicker and ~1 mph faster."
With (VVT-i) – Variable Valve Timing (You No Longer Have An (EGR) Valve)
No (EGR) Valve With (VVT-i) – Variable Valve Timing(VVT) systems have made Exhaust Gas Recirculation (EGR) valves obsolete. (EGR) valves put smog causing nitrous oxides back into the intake manifold. Consequently, The (VVT) system controls the timing to leave inert gas in the chamber for the next combustion cycle. As a result, Controlling the combustion temperature and the production of nitrous oxides.
In internal combustion engines, exhaust gas recirculation (EGR) is a nitrogen oxide (NO x) emissions reduction technique used in petrol/gasoline and diesel engines. EGR works by recirculating a portion of an engine's exhaust gas back to the engine cylinders. This dilutes the O2 in the incoming air stream and provides gases inert to combustion to act as absorbents of combustion heat to reduce peak in-cylinder temperatures. NO x is produced in high temperature mixtures of atmospheric nitrogen and oxygen that occur in the combustion cylinder, and this usually occurs at cylinder peak pressure. Another primary benefit of external EGR valves on a spark ignition engine is an increase in efficiency, as charge dilution allows a larger throttle position and reduces associated pumping losses.
EGR valve the top of box on top of the inlet manifold of a Saab H engine in a 1987 Saab 90In a gasoline engine, this inert exhaust displaces some amount of combustible charge in the cylinder, effectively reducing the quantity of charge available for combustion without affecting the air-fuel ratio. In a diesel engine, the exhaust gas replaces some of the excess oxygen in the pre-combustion mixture.[1] Because NO x forms primarily when a mixture of nitrogen and oxygen is subjected to high temperature, the lower combustion chamber temperatures caused by EGR reduces the amount of NO x the combustion generates. Gases re-introduced from EGR systems will also contain near equilibrium concentrations of NO x and CO; the small fraction initially within the combustion chamber inhibits the total net production of these and other pollutants when sampled on a time average. Chemical properties of different fuels limit how much EGR may be used. For example methanol is more tolerant to EGR than gasoline.[2]
So thermal management should assist an ECU reflash affecting EGR function.
...
When compared to the 0.025 inch steel gasket it replaces, a quarter inch thick phenolic insulator will conduct 200-1000 times less heat! Although the insulation benefits increase with thickness, ¼ inch (6.4mm) sheet was chosen because this is the thickest that can generally be used with stock mounting studs and bolts.
....
Done this in my previous Nissan Cedric using 10mm phenolic board. Used high temperature glue to make the inlet surface of the spacer smooth to avoid unnecessary turbulence. Result: smoother engine, a bit more powa, better FC.
Done this in my previous Nissan Cedric using 10mm phenolic board. Used high temperature glue to make the inlet surface of the spacer smooth to avoid unnecessary turbulence. Result: smoother engine, a bit more powa, better FC.
1998-2000 LS400 intake manifold gaskets sandwich a resin material between thin metal.gaskets as a heat barrier.
Lexus parts department is ordering a set of intake manifold gaskets for 1990-1997 LS400 to see whether template is same as 1998-2000 LS400.
05-04-20, 08:46 PM
One of the possibilities for reducing the intake air temperature is to install a cold air intake. However, another possibility is to reduce the heat conduction from the hot engine to the intake manifold by thermally separating the two. By replacing the steel intake manifold gaskets with an insulating spacer, heat conduction to the manifold can be greatly reduced. The best material for the spacers has a low thermal conductivity, high compressive strength, is able to withstand up to 300 degrees F (~150 degrees C), and is affordable. Phenolics, with excellent insulating properties, high stiffness, and the ability to withstand 500+ degrees F (260 degrees C), are commonly chosen for similar applications. Additionally, the coefficient of thermal expansion of a phenolic is similar to that of aluminium, which helps to reduce sealing problems in this particular use.
Building upon a previous spacer design, I was able to create a CAD drawing of the item and got several quotes for making a production run of approximately 50 sets potentially utilising everything from standard milling and machining to abrasive water jet cutting. I found a competent local company and after working through some initial fabrication problems, I was able to get sets made that were of very high quality. Too bad you can't see them after they're installed!
Being a mechanical engineer by day, I was somewhat doubtful about the method, but after giving it some thought, I decided to purchase the program and give it a shot. After using it for the past several months, I have been absolutely amazed by The Home Dyno's accuracy and repeatability. The program outputs a graph as well as a load of data that can be dumped into Excel or other spreadsheets and then manipulated. It also corrects for altitude, weather conditions, driveline loss and aerodynamic drag. In addition to the graphical output, the HomeDyno also outputs several pages of numerical data. It really is neat little program and I highly recommend it, especially for those all wheel drive vehicles that cannot so easily be dyno'd.
The basic function of the insulators is to reduce intake manifold temperatures, so what better way to test than to record and compare temp data before and after the install? I took the temperature readings from the front centre intake runner using a professional quality CPS T200 temperature sensor with a time constant of the order of 5 seconds. The sensor was mounted on the front middle intake runner for all tests and the vehicle was driven as close to 60 mph (~100 km/h) as traffic would allow. After the driving test, the engine was allowed to idle for a sufficient time to show the maximum temperature.
My best time prior to the spacer install was a 15.360 at 88.469 mph with a 60 foot time of 2.209 seconds. This was during last year's season where I ran 29 races at Thompson Drag Raceway in north-eastern Ohio. The first time back at the track this year I ran a best of 15.262 at 89.315 mph with a 60 foot time of 2.282 seconds and with the insulators as the only additional modification. The temperature during both races was about 55 degrees F (13 degrees C). To summarize, I was ~0.1 seconds quicker and ~1 mph faster, all with a .073 second slower launch.
No (EGR) Valve With (VVT-i) – Variable Valve Timing(VVT) systems have made Exhaust Gas Recirculation (EGR) valves obsolete. (EGR) valves put smog causing nitrous oxides back into the intake manifold. Consequently, The (VVT) system controls the timing to leave inert gas in the chamber for the next combustion cycle. As a result, Controlling the combustion temperature and the production of nitrous oxides.
