Cool, thanks for the info! At what RPM did you see the float and about how many miles did your springs have on them.. also, are you using ti retainers or yella terra rockers?
thanks

 

<font color="blue">Hi guys,

I'm a new "member" to this site but have been "prowling" around quietly for quit some time. I hope I am not ruffling some feathers here but this is an exerpt from an Email I received from a VERY reliable camshaft source. I editted some of the content for security reasons but the main topic is still there.

Read into it what you will, but be forewarned, this is factual and not hype!

Ed Curtis
FlowTech Induction Systems
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LS1 Speed Secret: "Quiet" Springs Deliver More Power:

Recent tests conducted on Chevrolet LS1 engines have confirmed the LS1's sensitivity to valve train noise. During the development of a roller rocker conversion kit, we noticed that any slight amount of valve train noise would cause the knock sensors (there are two of them located in the engine valley) to pull timing out of the engine, resulting in a significant reduction in power.
Recent tests of dual valve spring assembly for the LS1's showed a significant power increase over performance "beehive" designs such as the Z06 spring in the RPM ranges above 4800. Close investigation points to the fact that the close wound coils at the top of the "beehive" design are clashing loud enough, (they are supposed to clash to help control harmonics in the "beehive" design) for the knock sensor to identify the noise as "engine knock," resulting in the computer pulling timing out of the engine in an effort to eliminate the alleged "knock." This causes the power curve to flatten out noticeably just where the engine should really be making power.
Our springs (dual coil spring without a damper) do not rely on coil clash to control harmonics. Instead, the dual coil design relies on two different frequencies of the component springs and a slight interference fit for harmonic control. In addition, if one of the component springs would break (we have had zero failures!), the other spring would not allow the valve to drop into the cylinder and destroy the engine. The springs show excellent "quiet" harmonic control to 7500 RPM. This translates into as much as a 22HP increase over performance "beehive" designs in the RPM range above 4800. Similar noise problems can, and do, occur on any vehicle equipped with a knock sensor "Quiet" power can be subtle and overwhelming!!

 

Ed,

Reading that makes you wonder which company and which springs they are talking about.

Bret

 

Hmm.. I was hoping that my car was going to be quieter with the 918's. The last set of heads I had, I ran 918's on, the set of 5.3's I have now with 978's are LOADS louder than the set that I had with 918's... all of this is giving me a headache now.. The NEW heads are being assembled Thursday and I have told Terry to install the 918's with Ti retainers.. I guess I'll know if I made a good decision or not VERY soon.

 

One thing in the email Ed posted that I disagree with is the "interference fit" between the inner and outer springs.. this relates to FRICTION between the inner and outers.. which in turn generates heat. That energy is lost as heat and is lost horsepower. A single spring doesn't have this. Also, how can an "interference fit" not cause the same valvetrain noise that the email accuses the beehive type spring of having? I was under the impression that the majority of valvetrain noise is not from the springs themselves but the physical action of the valves "slamming" the seats when they close, due to the high ramp rate of the cam and the stiff spring pressures. That has to make more noise than the coils clashing..

What does everybody think?

 

How would the "beehive" springs compare to the duals springs if it didnt pull timing?

Like if you used ls1edit to make the knock sensors as sensitive or to use the knock out box for the sensors?

would the power be the same or higher with it not pulling timing?

 

I'm not convinced that the beehive springs will cause the PCM to pull timing. Surely GM wouldn't use this type of spring in the LS1 and LS6 if it did.

 

everyone would see KR if that were the case. I don't see any KR with my 918s

 

that EDC guy was from flowtech, which is a part of HOLLEY
so im guessing he was pretending to get an email from someone else, when it was really from himself
basically trying to say a holley product was the best thing to buy
Im new to the valvetrain game, so what type of springs does holley make, or one of their subsidaries?

 

Lunati?

 

...the "stories" about the many broken 918 springs are not stories; they are real events...

...these springs have broken so often that our moderator, Pro Stock John, placed a warning on this page telling people they should contact the manufacturor and request reimbursment for collaterial damage (broken pistons, valves, blocks, etc.) caused by this DEFECTIVE product...

...the warning about these springs remained on the board as the first post in this Forum for many weeks and it was only recently removed...

...so buyer beware!

 

and what about the blue striped ones?

 

I KNOW there was problem with the OLD 918, but the BLUE STRIPE ONES haven't shown a problem

Robert.. do you realize that we are talking about the BLUE stripe 918's ?? The original failures were on the inital springs and the BLUE STRIPE was added to denote the newer springs that DO NOT have a problem. So, once again, I challange you or anyone else to produce an actual broken BLUE STRIPE 918 spring or a picture of one.. or even someone who can personally testify to breaking a BLUE STRIPE 918..

 

There have been many more REV springs broken than the old 918s. People keep spreading info about how bad 918s are and they dont really even know about it and have never had firsthand experience with them. I still stand with my original opinion that "BLUE STRIPE" 918s are the best single spring available for this application for many reasons. I dont buy into that KR bullcrap as I've never seen any with my 915s or 918 springs that was false.

 

At some point all springs wear out, but what is the expected life span of 918s in a H/C ls1 driven hard?

 

I'm going to be running the TSP 231/237 and I fully expect to get 20k miles out of mine. And I run the LIVING HELL out of my car.

 

hell I have non-bluestripe 918s that I bought during the broken spring rash. Robertbartch...I repeat...name one instance of a blue-stripe 918 failure

 

...another person on this board broke a comp cam spring today after 1K miles...see his post....

.....kinda proves my point - this company does not have any quality control procedures...

..buyer beware!

 

that is NOT a 918!!!!

 

I think you won't be sorry with 918's and Ti retainers. That's what I have, and I just made some high speed/high rpm runs down a three mile course with no problems. Also, my valve train is as quiet as stock.