Anyone running a Thump Racing tensioner?

[Maynor]

on a road course?

Any feedback on any difference it made? I just installed one on my car (Nove'id 99 Cobra) and I'm hoping it helps reduce belt dusting and shredded belts.

Just curious to see what other results folks have had up to and including "no difference at all" comments.

 

[TroyV]

It looks like a very nice piece, though there is nothing noted on what spec the spring is, or how much more force it provides over the stock piece. I would call them and ask if the spring is just the same, or if it is actually a stiffer/stronger spring. I would not take someone's word for it, and ask for detailed documentation on what the spring actually is. One could argue that if the spring is the same, that the tensioner does nothing more than the stock one.

Can you elaborate on what you are running for pulley's and idlers? How long are your blower belts lasting before you shred them, and whose belts are you using? How many track miles are you getting per belt, and how many street miles?

 

[Maynor]

From everything I've read, its most likely a stock Ford spring but they claim it is oriented in a manner that gives "30%" more tension. However, I haven't confirmed that yet.

The "thicker" aluminum arms could possibly minimize side to side pulley deflection which is a bigger issue than I thought. I was using the steel Ford tensioner when the belt jumped a rib, three times in the past month. This is after two years of hard track abuse. It might have been a fluke. Who knows.

I've noticed I've had to replace the tensioner every few years to bring belt reliability back in line. On a serpentine setup with one long belt (versus 03 Cobra), the reliability isn't as easy to get in my experience.

I'm running a 115.x" belt which is a lot of belt. 99 Cobra 8-rib setup, 90 mm pulley on the idler.

I've only done one drive with the car since I installed the pulley ( old used belt put on for now). Tentative observation shows a little less belt dusting and the seat of the pants shows a slight improvement in boost response. However, I'll reserve judgment until my next track event. That is the real test.

 

[Quadcammer]

Hey john, to update you here, I've been beating on my junk for the past couple days and so far the belt looks perfect. Might have just been a coincidence.

 

[Maynor]

Thanks Oliver. I don't know why I felt compelled to buy something that isn't proven this go around but I did.

I'll know for sure in a month and your results are encourging. They are belts. Sometimes, it just happens.

 

[Maynor]

Update, after two open track events, I have a dramatic reduction in belt dust in all the usual places. 90% reduction is my guess.

I'm surprised and impressed. No other changes to the belt setup. I was not expecting that dramatic a result and the only explanation I can come up with is even with a supposed stock spring installed, the beefier arm flexes less than the Ford Steel piece I've been using for years..

Fascinating result.

 

[brkntrxn]

Interesting....

BTW, what kind of belt are you using. Gates?

 

[Maynor]

Yep.

 

[Quadcammer]

Update, after two open track events, I have a dramatic reduction in belt dust in all the usual places. 90% reduction is my guess.

I'm surprised and impressed. No other changes to the belt setup. I was not expecting that dramatic a result and the only explanation I can come up with is even with a supposed stock spring installed, the beefier arm flexes less than the Ford Steel piece I've been using for years..

Fascinating result.

John, glad to hear that the thump is working well for you.

I've really tried to limit spending on the cobra and $380ish for the tensioner is not something I'm looking to spend, but I am happy to see that there is another option out there.

My belt seems to be ok as well, so good for the both of us.

 

[Maynor]

Concur on not spending a lot on the Cobra. I'm betting the stock steel one would have been fine for the next go around too. For a change, an experiment that paid off in terms of less slip. Now, do I keep the steel tensioner or sell it? Decisions, decisions.

Unfortunately, I just committed some of what I hope will be that last of any upgrade funds on the car (short of consumables) for the next 5 years or longer, for a real suspension.

I don't plan on making any more power and in fact, may detune the car further to keep it road course reliable. The safety stuff is in. The power stuff is in. The suspension stuff is soon to be in and I'm hoping to keep it at this revision level for the remaining life of the car and just drive the piss out of it.

In this hobby, those are famous last words and I'm trying to believe I'm at the bottom of that slippery slope and that only maintenance costs should present themselves in the future....

Anyone want to make a bet?

John

 

[Quadcammer]

ok, what suspension mods have you purchased?

My latest purchase was the MM Solid Steering shaft.

 

[Maynor]

I came > < close to an Agent47 front end but decided on an MM k-member, race coil over struts/shocks/spring for the front and rear etc. I held off on the solid steering shaft for now pending more feedback from others... so I'm particularly interested in yours when you get it installed.

 

[Quadcammer]

wow, thats a hefty purchase there. I'm sure you'll love the mm kmember/ca's and coilovers.

I have my heart set on a 993 porsche, so I've told myself to cool it with cobra stuff, although that MM k member is really a great mod.

I should have the shaft by thursday, so I'll post up a review by the weekend if its not pouring rain.

 

[mu22stang]

I'm interested on the feedback for the solid steering shaft...

Maynor, this may or may not be pertinent, but I know the extra load on the serpentine system can have detrimental effects on the stock idlers. I believe they are the same 90mm cast units as on the 03/04s, and those readily explode once a smaller belt or smaller pulley combinations are thrown in the mix due to the increased radial load. If this tensioner increases the serpentine load similarly, aftermarket idler/idlers may be a good preventative mod.

 

[Quadcammer]

although I had some issues with the install, steering wise it was like getting out of a mustang and getting into a bmw.

much tighter, more solid, and definitely more responsive.

I'll need more time to wail on it for more feedback.

 

[jbp99cobra]

John - I am very interested in hearing some long term results on the tensioner. I have gone through one stock tensioner already.

Quad - Same thing, looking forward to more feedback on the steering rack especially if it makes the steering as tight as you are saying. Very exciting!

 

[mu22stang]

although I had some issues with the install, steering wise it was like getting out of a mustang and getting into a bmw.

much tighter, more solid, and definitely more responsive.

I'll need more time to wail on it for more feedback.

That's good news. I've looked through the install on MM site a few times, and I can definitely see some steps that aren't exactly straight forward. What issues specifically did you run into. Sorry for the off topic discussion, just very interested in this part. :beer:

 

[Maynor]

My next thrashing is in a few weeks at Watkins Glen. I plan to measure the rate of belt dust deposition on key parts to get a better idea of the performance.

I did figure out something about the tensioner. Thump uses the S197 tensioner spring (round stock) versus the SN95 tensioner spring (flat stock). How much more tension this spring holds I'm still trying to figure out so if anyone has specs, please pass them on.

 

[Quadcammer]

That's good news. I've looked through the install on MM site a few times, and I can definitely see some steps that aren't exactly straight forward. What issues specifically did you run into. Sorry for the off topic discussion, just very interested in this part. :beer:

See the new thread.