INTRODUCTION


I have used the IPD plenum for 2 years or so and have been very pleased with the performance of this mod. “Turbo” Mike who designed the plenum has been a great source of tuning information and an overall fantastic guy! He is candid, honest, and doesn’t pull any punches when it comes to cars and car enthusiasts! He also does not sell anything that doesn’t work and he stands behind all his products. When he asked me to evaluate his newest product, I jumped at the chance…

The new products from IPD are turbo and header insulator blankets. These have a proprietary multi-layer construction, which includes an inner layer of inconel alloy and stainless wire and an outer layer of a carbon fiber-look material. Inconel is an expensive alloy of nickel, chromium, iron, manganese, and other elements. It was first used as an insulator for the interior of jet engines. It is currently used in the exhaust of the McLaren supercar. It can handle a constant temperature of 2200 F. These blankets are custom fitted to each model of turbo and header.

The theory behind these blankets is not new. Smokey Yunik wrapped headers of Chevys with insulation material in the 1960s. He claimed the hotter the exhaust in the header the more power you could make. His explanation was that exhaust gases cool quickly from the combustion chamber progressively down the exhaust system. As the gases cool they slow down in the pipes causing a relative backpressure. If the gases are maintained at a higher temperature they move quicker out of the exhaust system and the cylinders are more effectively scavenged. Thus, the engine is more efficient and powerful.

When you introduce a turbo(s) into the system things get more interesting. Since the turbo derives its compressive energy from exhaust flow, maintaining greater heat and velocity in the gases has a positive effect on boost threshold (spooling). If exhaust gases have more energy (speed) the turbine will spin faster and at lower engine speed (rpm) giving less lag and harder turbo hit. This effect is accentuated by adding blankets to the hot sides of the turbos. Then the exhaust is insulated from the head all the way through the turbo. These are the two primary ways the blankets can benefit 996/997TTs.

Additionally, there are two secondary benefits as well. By insulating hot exhaust pieces underhood temperatures can be lowered which may help preserve electronics and wiring under the bonnet. IATs may also be lowered. Secondly, by insulating the hot side of the turbos, this lowers the effect of radiational heat to the cold side thus potentially helping with lowering IATs.

These pics show the outside and the inside of the turbo blankets and header blankets respectively.

 

THE PRODUCTS AND INSTALL

After IPD had the blankets cut specifically for my Tial A28 turbos and for my EVOMS Clubsport headers, I received them in two boxes. One contained the turbo blankets and one contained the header blankets. The outer surfaces have the grayish-green carbon fiber-look material. The inner surface has a stainless steel mesh. The inconel alloy is the first of several layers of insulation beneath the stainless wire. The blankets are firm but are flexible material. They are sewn with coated stainless wire. Due to this stainless wire you should wear gloves while installing to avoid cuts to your hands. The header blankets attach to the header bolts via the three crush washer holes. They wrap around the header and close with the springs and hooks. The turbo blankets simply wrap around the hot side of the turbos and are secured with the springs and hooks. The turbo heat shields are removed during installation since they are no longer needed and get in the way of the install. The whole process was fairly painless (for a P car) and took about three hours. The fit was excellent so we fired her up. The first thing we noticed was that the engine noise was softer without as much valve noise being transmitted through the headers.There was some smoke present for a few hours and an interesting smell for a few days so don’t be alarmed!

The first three pics are macros of the interior of the blankets and the exterior carbon-like material. The last two pics are of the install.

 

TESTING

Initially, I tried the car with just the turbo blankets installed. I just went for a short test drive without the performance box. The car felt subjectively more responsive and seemed to boost quicker. We let her cool down and then installed the header blankets. I had some baseline (before the blankets) Pbox data in which I ran some 60-130s entirely in fourth gear in hot humid conditions very similar to what we are having now. The best of these was 6.92s. The reason I ran them all in one gear was to eliminate the huge variable of shift speed. I then drove out to the same spot and ran several more 60-130s with the blankets installed. The car went progressively faster on each run topping out with a best 6.64s.

As you look at the chart and graphs, note that the red speed line and green g line is “with blankets” and the blue speed line and black g line are “without blankets”. The software wont let me exactly superimpose the lines for some reason. As you can see, the blankets have a noticeable advantage in turbo hit/spool. The blanketed car gets about a 1.7 mph advantage in the first 1.5s of the pull. After that the car pulls slightly better throughout the entire rev range. I have enlarged the first part of the pull to better show the spool advantage which is about 13% better spool than without the blankets! This spool advantage was seen in all the runs. This has big implications for roll on races in “Mexico”!

Two more install pics followed by PBox chart, 60-130 run, and enlarged first portion of the 60-130 runs so you can see the spool advantage of the blanket mod.

 

DISCUSSION

These blankets will soon be available at IPD. If you want some, you must know your exact header style and your turbo model. Greg and Mike have patterns for many different header/turbo combinations already. However, they may need to lay hands on one like yours if they don’t already have one. Todd Z and Ian were very gracious to send a set of headers like mine to IPD so that a pattern could be made. Once the pattern is available the turn around time is only 2-3 days. Ask Mike about the pricing.

I will continually be evaluating these products and plan to post updates as I learn more. Next month I intend to try these blankets at the Texas Mile where I have Pbox and video for six prior visits. Hopefully, this mod will help me get that magic number and that monkey off my back!!

Finally, I have no connection to IPD or any of the manufacturers of these products…

 

Nice write up.
Mike and Greg are great. Turbo Mike is the man. He really helps people out like your his long time buddy.
Now if we could only get some more of his tricks on our cars...

 

Great job on the testing and write-up Mike. I would be surprised if these didn't make a difference, especially after a couple of runs with hot insulated headers and turbos. I suspect in cooler weather the difference would be even more dramatic. Is there any concern of the turbos getting too hot? It would be interesting to see the EGTs of insulated vs non-insulated but that would require more work for you.

 

Thanks!!

I suspect you are right about the cold weather... I will find out for sure soon!
Turbo Mike has already tested EGTs on his car. Only 10 or so degrees so not significant. Long term effect of turbos and headers is a concern. I guess we will find out...

 

Is there a risk that the life of the turbo bearings/cartridge will be shortened because of the hotter oil/water temperatures?

 

mike congrats, they look good, now you should be able to break your 5.54 run 60-130 without even raising a lb of boost. we love to see you raising the bar and setting new record for A28s. congrats mike

 

I love the idea of the Header and turbo blankets, I have a question when using with K series turbos that are oil cooled, I have used blankets extensively before with water cooled turbos but never with oil cooled is this an issue? as it is my impression that the oil cooled turbos are more sensitive to overheating and resulting damage the bearing. I can not qualify this with any data just a hunch?

 

Those really sound that they would be a must in colder weather.....

 

Excellent write up Mike. Thanks for the hard work and sharing the info!

As my car is equipped with VTG turbos, I share TTdude's concerns about the turbos getting too hot.

 

Thanks Rich! Hope you are right about 60-130!

Thanks John. I believe the colder it gets the better too!

 

I considered this turbo longevity issue myself. I have had these on only about a week. Turbo Mike has been running them on his DD (997 GT2) as well as several friends VTG cars for 4-5 months. None of these folks has had an issue but that is all the info we have at this point. I definitely give her a good cool down before shutoff every time I drive.

 

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