RICESP Water Injected RX7

[RICE RACING]

Originally Posted by Grant M

That looks like someone has done bird shit welding in there! What's happened too it? What turbo did you swap too and why?

Too much heat retained in the housing causes that, similar thing that happens to exhaust pipes when you heat tape wrap them, the material structure breaks down with time and the end result is above.

*You must never ever insulate exhaust components or turbine housings* a heat shield is the only option to run, something with an air gap that can allow the heat to be rejected and flow away is the ideal.

A few posts back I reached the limit of this turbo in terms of the performance (over speed, too much turbine pressure) so I changed it. New turbo is my own specification

[RICE RACING]

Hey Grant, here is a good explanation into why heat wraps and turbo bags fuck the structure of the Iron and its derivatives *basically makes them DIE*
Taken this off the interweb, its not a bad explanation of the effects and what I found in this test

"Why Header Wraps Destroy Your Headers ... and *TURBO BAGS!!!*
Why Thermal Ceramic Coatings are Recommended

Regularly we are asked about, or have commented on the use of header wraps (header tape, thermal tape, heat tape). This issue is a real pet peeve of mine. Good or bad about a product I will give my opinion based upon direct use and fact, and this stuff screams "Do Not Use on Exhaust Headers!"

THE FACTS:

* Header wraps are designed to keep the heat in the header to improve scavenging of the cylinders. Keeping the heat in the header allows the exhaust speed to remain high. (the right idea)
* Header wraps, by keeping the heat in the header, also reduces the radiant heat in the engine bay.
* There are no header manufacturers that I know of that will warranty their headers if any header wrap is installed on their products.
* In most cases the header wrap damages the headers beyond repair. (I will explain below)
* If you run a lean mixture, you "may" see a slim performance gain using header wraps. A rich mixture may show slim to absolutely NO gain in performance.
* If you do not mind replacing your headers and header gaskets regularly, and you like that ugly look of a wrapped header, go ahead and use the heat wrap.

BACKGROUND INFORMATION:

In the past, almost all NASCAR and other racing engine builders and crew chiefs used header wraps for the added power gains and thermal control benefits offered by their use. Problems occurred when these same teams had to replace the headers after each race (NASCAR) due to the wrap being about the only thing holding each header together. Most engine builders, crew chiefs, and definitely the header manufacturers themselves do not promote the practice of installing these wraps directly on the headers! They now utilize the thermal coatings that are chemically and electrically applied to the headers. Popular header coating services include Airborn, Jet Hot, HPC, and some header manufacturers now applying the thermal coatings in-house.

Imagine having to replace a $1500.00+ set of headers after each race weekend! Few but the most financially well-off race teams can afford to do this. Also, consider the downtime in remaking a custom set of headers. Most custom header makers do not have copies readily available.

I believe that the wraps are good to protect various underhood 'items' from heat, but not for the use of holding the heat in the header. For example: you can use the wrapping for the protection of fuel and oil lines, wiring, covering a starter motor, etc.

Cool air needs to be around the header, and insulating it with a wrap to hold exhaust heat in makes the header material surface temperatures reach near molten levels. When you wrap the header you trap the heat in the header, but also suffocate the material that needs to breathe to dissipate heat for it's own survival.


Engineers, Metallurgists, and other experts out there will state that there is no way that the material can fail because it was designed to withstand the internal temperatures of exhaust gases. This is very TRUE! But, when the header is not allowed to cool (or breathe) so as to dissipate those extreme temperatures that the wrap is controlling, you have now developed a heat absorption that compares to thermal friction. This causes temperatures to continue to rise beyond the normal exhaust gas temperatures (EGT's) the header material was designed to withstand. This holds true as with most any type insulation.

Try this experiment the next time you launder a load of bath towels and then dry them. Immediately pull them out of the dryer and just toss them in a snug pile on your bed. Now leave them there for a many hours, even a day, and then open them. You will find that there is still a considerable amount of heat left in the center towels. This heat, even though the outer towels and bed are normal room temperature have been able to contain their heat. This is a simple thermal insulation test, but compared to your headers you have an internal heat supply constantly coming from the engine when running. The heat on the outside portion of the header material is trapped between the wrap, and soon will begin to fatigue the header. This build-up of heat is amplified by the wrap. Your freshly dried bath towels do not need to breathe, your header material does.

The EGTs stay the same but the properties of the header material changes by amplifying the temperature due to the insulation. This action goes against normal laws of thermal dynamics, but this effect is fact, and you have to pull the ears off most engineers before they believe you. This is the trouble with plenty of education, but a lack of something that is often just as important, that of "common sense"! If you decide not to believe these statements that is your choice. Go ahead and install the header tape on your headers ... we'll be happy to sell you a new header set!



HERE ARE A FEW TEMPERATURE READINGS TAKEN AT DAYTONA MOTOR SPEEDWAY:

Below are the test parameters and results using Jet-Hot Coatings? coated and uncoated headers:

(10 Laps; the same engine and car with identical headers; one header set is uncoated, one header is Jet Hot? coated. The engine is operated between 6,900 and 7,500 RPM, and temperatures are measured immediately after the last lap with the engine idling at 2,000 RPM with identical sustained EGT's of 850? F.)

MEASURED AT:

JET-HOT? COATED

NO COATING

COATED DIFFERENCE
1" from engine

300? F.

750? F.

- 450? F. Header Coating Benefit - Thunbs Up
2" above header port (on header)

210? F.

300? F.

- 90? F. Header Coating Benefit - Thunbs Up
1" above floor pan (in car)

115? F.

165? F.

- 50? F. Header Coating Benefit - Thunbs Up

Pretty impressive difference, and with any of these coatings you should take care to not damage the coating. The thermal coating becomes part of the header material. Most of the other coating brands are comparable to these figures (if they are multi-layer, inside and outside of tube applied and using proper materials).


SOMETHING ELSE THAT FEW RACERS and CAR OWNERS REALIZE:

Headers Oxidize!

Under normal use, and even more with higher EGTs and header surface temperatures, your headers will oxidize and small amounts of material is actually removed from the headers. This means your uncoated headers will become lighter and weaker over time.

Examine these actual test numbers:

* Mild Steel (1010) uncoated header exposed to continuous 1200? F. in normal air will have a weight loss percentage of roughly 25% with only 10 hours use at this temperature.
* Stainless Steel (410) uncoated header will have roughly 8% weight loss in the same 10 hour period.
* A coated mild steel header will have NO weight loss at temperatures up to 1200? F. In fact it will actually gain a bit of weight! Between 1300? F and 1600? F the coating will begin to show signs of mud cracking or like the look of lacquer checking. However, limited diffusion takes place between the coating and the substrate, producing a very thin film of iron aluminide, which continues to inhibit oxidation.

Header Oxidation Graph



Now, think about the information provided above and consider the added thermal stress generated by the header wraps. What do you see? Remember that the wrapped metal cannot cool properly and the header wrap is causing the material to super-heat and pre-maturely fail!

BASIC UNDERSTANDING:

Because of the expanding gases, if you have had the experience (as I have) to see first hand what header warp has done to a header, you would notice the locations on a header where the material failures occur. This is typically where a step would be, or where there is an expansion pulse of exhaust gases inside the header tube. I have had headers in my hand where literally the only thing keeping the header in one piece was the wrap. Whole chunks of the header material was gone, simply melted away. If you were to speak to most "engineers" (I use that title with caution) they will probably tell you that aliens stole the metal as the car was racing around the track! They say this because the conclusion that the wrap is causing problems is not part of normal metallurgy and thermal dynamics theory <key word>. The header wrap allows temperatures between the wrap and the header to turn the material molten.


IN CLOSING:

We know that header manufacturers will NOT WARRANTY a header which has had a wrap installed on it. We know that I (and many others) have personally witnessed, tested and inspected headers that have been destroyed after running headers wraps, and these headers were on a perfectly tuned engines.

Just because an item or product is advertised for a specific use does not mean it does not do what the promotion or advertisement states. But, it also does not mean it is the best choice either, or that there are negative consequences. We have all seen TV commercials on all of these "medical miracles" and "overnight diets" that do such feats as fast weight loss and re-grow your hair. How often have we laughed at the side affects, like the most common being penile failure. Oh sure, I want to take some drug if my hair starts falling out that makes other body parts fail to function. NOT !!! Those pharmaceutical companies can pucker up and kiss my backside! I'd rather have function than hair!

The same can hold true with automotive and marine products. Heat wraps are great, just do not use them ON the header. Use them on a device or component on your vehicle that you are trying to protect from header heat.

If you want a true thermal barrier that will reduce thermal loss in the header, reduce under hood temperatures, and make a few horsepower in the process, have your headers thermal coated by one of the many companies available or the header manufacturer themselves. Most all of the coating companies offer inside and outside, multi-layer coating as standard. DO NOT allow your headers to only be coated on the outside, or just a single layer application! This is not a complete or quality process.

*NOTE my EGT is perfect! pipes up to the turbine housing look like new as do the EGT probes* so 100% turnine heat bags FUCK your turbine housing!!!"

[RICE RACING]

Originally Posted by GySgtFrank

Good info. This has been my experience with header wraps as well. Headers rust away fast enough on their own if uncoated. Wrap them and they last maybe a quarter of the uncoated header lifespan. It's interesting that the same type of degradation can be seen with turbo bags. I would have thought the cast iron would have stood up to heat soaking better than that. Guess not, thanks for the heads up.

No worries, I always wanted to prove that TURBO BAGS are fucking shit, and as you can see they 100% are

I suppose like I said in my first post if you are a show pony or drug racer or generally some fagot who does not actually use the power of your car often then you may find that "nah man, bags are fine, never ever had a problem" you will only never have a problem if you do not use the power (I.E. Generate enough heat!@ consistently) to degrade the housing.

My last housing was a 1.00A/R twin scroll size, and it was on for a few thousand km until it became a restriction and I swapped it out, it ran a bag but because the power level was low and not as much true proper high speed testing was done it did not look this bad. It takes BIG POWER and repeated power after power runs to accumulate the "heat" in the housing and not let it dissipate to over stress the housing. (NOTE: one or two consecutive laps on a low speed track racing for a plastic trophy!! is not high stress LOL) Its just proof of how hard I run my set ups in the name of true proper endurance testing and in that environment BAGS are a KUUUUUUNT!

Originally Posted by silverfdturbo6port

I've used bags and wrap n street machines for many many years with no issues. Even with drag racing, autocross and numerous 180+mph pulls on 100* days I've never seen them "BDC" nor myself turn into a "KUUNT" but those are not harsh conditions like a race car as stated by Peter.
But for a dedicated "Race" car I will guarantee you will see the effects like in the OP.
But for daily driving/street use and you want to keep the bay temps down then Bags, wrap, shielding, heat coatings all work great.

It's a function of power, restriction, retained heat, time used at high power.
Anyone familiar with FD3S twin turbo systems who has used them at high power (1.5bar boost @ ~400bhp or so) and over a huge length of time (say 50,000km+) will attest to the similar degradation of manifolds and turbine housings (non insulated!)

If you are making lower power, use it less frequently, have larger housings, turbo's etc all of this simply means you have less if ever any likely hood of seeing such things

*If you are making the power (with associated heat input!)
*Use it often and at high duration
*Even on a T4 platform with the biggest housing you can run and super low restriction outlet *see proven tests* you will fuck the housing if you insulate it... proven.

[Grant M]

will you ceramic coat your manifold or stay with the heat shield? iv been looking at whether coating the turbine housing is a good idea? as i would have thought you dont want to keep a huge amount of heat in there once the engine is switched off and cooking the CHRA, although any rotary turbo owner shouldnt be turning their car off after thrashing the arse off it without cooling it down first.

my turbine housing runs extremely close to my LIM, within 10mm, maybe less. the LIM is going to be polished to help reflect the heat away however i want to be able to stop the heat from the turbine housing and i may not be able to fit a heat shield and this is where i thought of actually ceramic coating the turbine housing, what do you think i should do?

you got some pictures of the inside of the WI nozzle placement please?

with your new turbo spec are you planning to add more boost? see how far you can go with your CDI and WI?

[RICE RACING]

Originally Posted by Grant M

will you ceramic coat your manifold or stay with the heat shield? iv been looking at whether coating the turbine housing is a good idea? as i would have thought you dont want to keep a huge amount of heat in there once the engine is switched off and cooking the CHRA, although any rotary turbo owner shouldnt be turning their car off after thrashing the arse off it without cooling it down first.

my turbine housing runs extremely close to my LIM, within 10mm, maybe less. the LIM is going to be polished to help reflect the heat away however i want to be able to stop the heat from the turbine housing and i may not be able to fit a heat shield and this is where i thought of actually ceramic coating the turbine housing, what do you think i should do?

you got some pictures of the inside of the WI nozzle placement please?

with your new turbo spec are you planning to add more boost? see how far you can go with your CDI and WI?

You live in a great country so far as proper engineering so you can draw upon one of the few suppliers who do ceramic coating for F1 quality applications. Have a look at the RedBrick Racing EVO and the coating on their headers, that is the sort of thing you need, then you can fit in a stainless heat shield to the LIM no problem

E-Mail me and I will send you the picture you want, along with some other tips.

For me, I'm always testing and developing the best so the way I operate is I always release the old steps that have been proven and are behind where I am now, I'm always happy for other people to copy and benefit from my *old* knowledge just I don't really share the current developments until I find something (that is better) else through continual self learning ... that is my philosophy, you are never ever too experienced or know enough/everything, and the more I keep testing and proving water injection and its superiority for internal combustion engines the more I have to share with others who want the best *my old stuff I was doing people today copy and sell as current best practice/advice* its flattering lol Thus I don't openly disclose the Don Mega stuff, too many copy cats

[reid-o]

FWIW over the years--working at a few shops and having seen the market grow for turbocharged parts--a lot of the dangers of header wraps that apply to race situations and teams aren't the cause for failures with street driven cars. I completely agree with your recommendations but for different reasons, as I suspect that most header wraps, even the new composite ones, carry the risk of trapping moisture which compounds the rate of oxidation. Combine that with the fact that most headers are constructed out of the cheaper 304 material than 321 or 316 and you have a huge issue in some geographies. If you consider that the weekend warrior rarely hits wide open throttle, the moisture inside the wrap isn't always allowed to evaporate, but it still absorbs moisture through condensation every morning no matter what the climate is like, unless one lives in subsaharan africa. When I was working for a shop, i noticed that most of the cracked headers were from weekend "warriors" who hardly drove their cars, and while most of those customers chalked the failures to welding defects or the material not withstanding the power they were making, I always felt that there were too many cases to suggest that this was the case.

[UCTURBO]

Just a thought, but could alot of water cause a similar thing? Cast iron red hot then quenched with water? You would think the water would be well and truly steamed by the time it got to the turbine housing and have little effect. Its just a thought.

[RICE RACING]

No, that is not possible since water is a by product of combustion of fuel (without WI), so by your idea it would happen even without it
But you need to re read the information:
This only happens with sustained high load testing, it is thermal degradation of the turbine housings due to insulation and massive retention of heat energy.
The exact same happens to stock FD3S twin turbo systems with their restrictive turbine housings and exhaust manifolds where the cast iron gets eaten away and melted exactly like this (no WI involved) especially after a crack propagates then reducing heat transfer to a cooler part of the housing. *with thermal bags- there is no cooler part of the housing!*
Once you have a piece of metal hanging in the air stream without the ability to "reject" its heat to another cooler bit, that piece then becomes over stressed and much hotter as a result, and it gets "eaten away" this is what happened to the central divider in the split pulse turbine housing, it simply could not reject the heat fast enough (due to the thermal insulation of the turbo bag) and under sustained high load testing that piece got literally eaten away.
Without a turbo bag's retention of heat this would not happen.

[RICE RACING]

DILDO CANNON

[RICE RACING]

Dildo Cannon in your face