Ok, here's the poop in imho:

1. Yes, the Hose Techniques stuff is adequate, but barely. I have it on my car but wish I had used the Duro Blue. I knew better but could not find the Duro Blue when I did mine so I just went with what was "convenient". I have a piece of it in my shop and it is probably 4 times as thick, denser and will bend in half without kinking. It's what I would put on an airplane engine and have 100% confidence that it would not fail for years and years. There is no comparison with ALL the other crap out there.

2. I would not use silicone where it is transporting oil. I would only use stock Mazda hoses in those locations, and there are really only a few of them which require special bends anyway to have it fit correctly. But we were talking about the vacuum hose job, no?

3. The vacuum hoses transport air, so no problem with
silicone there. It's the right stuff to use, unless you are wealthy and can afford Viton. It is ridiculously expensive.

4. The kit is a ripoff, all you need is hose and a pair of
hose cutters (Sears) to cut it cleanly. The kit will not save you any time, and you'll probably need to cut custom pieces anyway since you'll probably want to make some larger radius bends to avoid kinking. Even ONE kinked hose will drive you insane.

5. Don't forget that as the hose ages it will tend to collapse easier, that's why I inserted the #1 springs inside to reinforce it in tight radius bends. That way it can't collapse. You would not need to do this with the Duro Blue.

6. You MUST check all the solenoids and check valves (one and two way) to do the job right. I guarantee you that some will be defective or questionable.

7. The engineer who designed this system was brilliant but a sadist.

8. I am going single when the time comes 'cause I never want to do this job again - ever.

 

RonK........thanks for all the great information.........seems as though I just read a thread the other day about someone doing the "vacuum hose replacement job" and they were talking about NOT USING silicone, had shown all kinds of pictures of what happens to silicone, etc.........so my assumption was that this was what they were talking about; the very same infamous "silicone hose replacement job" that everyone talks about..........seemed strange to me as well because a thought this was all vacuum hose and has nothing to do with oil..............will try to find that thread and attach it so you can see what I was referring to.........

Thanks again.

David

 

RonK......Here's the thread I was talking about.......... would appreciate your comments.........

David

https://www.rx7club.com/forum/showth...5&pagenumber=1

 

After seeing the hose techniques kit in person I decide strongly against it. I purchased my silicone hose through Baker Precision. Excellent qualtiy hose and it was less than $40 for all of it. I still have about 15 left over. Try www.bakerprecision.com Also RonKMiller is absolutely right about the cutters. Go to sears and pick up a pair of the Craftsman HandiCut cutters. They make perfect cuts in the silicon so there is no fraying/spliting at the ends.

eric

 

Not adequate? Are you talking guys talking about for racing or just street use?

 

The quality of the hoses SUCK. I have seen them. For ANY use...

 

I think it was a very interesting little experiment, but there are so many variables whenever you try to duplicate what's going on in the real world in a lab setting, and the manufacturers DO tell you NOT to use silicone in contact with oil. (although the author of the experiment says they don't! - he really needed to dig a little deeper)

I have issues with the experiment:

The quality of the silicone hose. I am not an expert on silicone, but generally speaking there are MANY different grades of quality in everything, and you usually get what you pay for.

The fact that heat is a catalyst and will accelerate chemical degradation by mutiples of hundreds or thousands as the temperature goes up.

Submersing the hose is not indicative of the type of exposure it would ever have in a car. The concentration of what ever chemical (and there are quite a few in motor oil) that caused the silicone to degrade that fast was 100%, and in the car, a diluted mist concentration may only approach 1 or 2%.

I still would not use silicone in direct contact with oil, and once again, if price is not an issue Viton is the way to go, but it is outrageously expensive.

I always like to buy the best quality stuff for the cheapest price, (and who doesn't?) and many times you need to go outside of the "automotive" world to find it.

Have fun with the hose job, take your time and don't get frustrated. It's probably the most difficult job on this or any other vehicle I can think of!

 

Has HT hose gone down hill lately? This is the first time I have ever heard anything negative about thier hose. They do give you way more than you need in thier kit, but I thought thier hoose was of excellent quality and was much thicker and more kink resistant than the stuff from baker precision. I bought the kit for my car about 1 1/2 years ago. I had absolutely no trouble at all with ANY of the hoses kinking and I did not have to use any springs like you guys have mentioned. My friend Dave Disney has done a couple of cars with the same HT hose and has had the same results. Are you guys making cutting the hose too short or what. I am very surprised to hear everyone dissing thier product.

 

hrmm... the 'kit' for sale at the rx7store has four sizes listed: 3.5 mm 4.0 mm 6.0 mm and 8.0 mm ... everywhere else i've seen only 4.0 mm and 6.0 mm. I would imagine having only two sizes would be a lot less confusing, but are the other two necessary or more useful?

 

which locations are you talking about?

 

How many non-seq guys went non seq because they had sequential boost probs? (probably all of them) That's seems to be the main reason why everyone converts to non-seq. Bet almost all non-seq guys wouldn't go non-seq if their sequentials were working correctly from the beginning...It looks like all the guys who are sick and tired of trouble shooting boost problems convert to non-seq. I still can't comprehend how you get more power from the same two turbos running them parallel.

Oh yeah, this is a hose techiniques thread right?

 

The 3.5mm hose that comes in the kit is *much* thicker then the 4.0mm. If there was a kit with 4 & 6mm only, I can see why it would look really cheap. The 3.5 of which there was 20+ feet of in the kit I just recently got was very thick, nice tubing. I don't know about the quality of the material itself; but it seems stout for the smaller, thicker tubing.

?

 

also, the site where the viton hoses are sold ( www.acmerubber.com ) lists them in inches.. the closest I found were .250" (6.35 mm) ID and .187" (4.75 mm) ID.. we are talking about ID here right? would a difference of .75 mm give me problems? also, what's a reasonable OD for the tubing?

 

I found the silicone hoses listed in more convenient sizes (4.06 mm and 5.99 mm) but I'm still curious about the ODs because they vary

 

agreed,...I purchased 2 general kits of yellow and that was plenty to conver all vacuum hoses, and small coolant hoses, and boost controller hoses...et.et

each kit = ~30, so even 2 kits @ $60 is 1/2 the cost of the other full rx7 kits

also ,the hose is great quality and has thincker walls for better kink resistance, and they stay on the very well