Testarossa Exhaust Options

Hey All-

Surely a common topic but most of the threads are old and not all of the products are still available or commonly available.

I want to make my 1987 TR a bit louder. Currently running stock exhaust, cats, etc. In my state I can register it as an antique and therefore don't require emissions.

Most of the threads I've reviewed state that the majority of sound is blocked by the pre-cat and cat itself. Therefor bolting on a $5k Capristo exhaust doesn't always result in the sound you may look for.

I don't need a ton of sound but I figured that the best bet might be to keep my stock muffler and replace the pre-cat and cat first with Hyperflow High-Flow cat etc.

1. Is a Hyperflow high-flow cat more recommended versus the cheaper "test pipe" cat delete options?
2. What exactly is the "precat?" I can't find that part anywhere online whether by Hyperflow or anyone else
3. Is Hyperflow still even around? I am having a tough time finding any re-sellers of that product line.

 

****, I just researched the Kreissieg system. Now I think I'm best just saving up $10k for that option with the valves. At least it'll sound as good or better than my buddy's 458!

 

I got the below cat deletes from ebay vendor (no affiliation), looks good but only made exhaust slightly louder.
https://www.ebay.com/itm/Ferrari-Testarossa-512TR-Resonated-De-Cat-Catless-Test-Pipe-Pipes/391346423784?_

Only after I put on a Tubi exhaust and custom pre-cat pipes did the exhaust sound louder, really kicks in after 4k rpms.

 

Better off with a tubi at 3k from eurospares.
Kreissieg is the one i showed you yesterday-pretty hard to source


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Personally i didnt like no cats because of the smell...
For precats tubi makes some for like 1200 usd; or a local guy can make those for u too.


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The precats are a terrible designed which i believe were on US models to pass emissions; they tend to melt over time and are heavy.
I posted about the tubi precats i bought but too lazy right now to look for it.


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You are most likely better off getting a custom stainless exhaust made for the car and by-pass pipes, it should be far cheaper. That's if you have access to a decent custom exhaust maker and doesn't charge the earth! Having seen the cost of these 'branded' aftermarket exhaust systems, the mark up is significant on them compared to my local custom exhaust manufacturer. He made a replacement quality full stainless exhaust system for one of my other classic cars, not including manifolds for around £600.

 

Stock exhaust is just embarrassing. Our cars don't go fast at least make them sound fast.

 

The stock sound of a tr with precats/cats and stock exhaust is incredibly quiet and boring to be honest. I initially put on Fabspeed test pipes and noticed about 20-25% increase in sound with a little crackle here and there with minor engine breaking on down shifts. I later added a quicksilver sport exhaust and noticed nice improvement in sound especially over 4K. My stock precats are gutted previously (to my knowledge). Honestly I was looking for it to be a lot louder but after having it for a while it may be just right. Loud enough while getting on it but not so loud that when you get out you cant hear anything for 5-10 min. Quicksilver does have an option to go louder (supersport) which basically has no can. Its almost straight. The rep told me it would be really loud and probably not what I was looking for originally but now I suspect it was exactly what I was looking for. Oh well! Note they do not really describe the differences in their tr exhausts that well on their website. Give them a call!

 

Loud is loud. Great sound does not need to attract unwanted attention. I love a F1 sound from the early 80s, but would not want it in my ear for hours on end.

I'm not a fan of some of the exhausts on cars today. Had an idiot in an M3 next to me in traffic everytime he let off the accelerator the car burbled and backfired. He thought it was great. The car was insanely loud, not a pleasant sound, just loud. Lots of camaros, mopars and mustangs have the same disease.

I have a tubi which came on my 308QV and it sounds nice at higher revs and have thought about an exhaust for the boxer. I just don't want something which is obnoxious. I've heard BB LMs on track and it sound great, but I would not want to live with that exhaust day after day. And it just attracts the wrong attention.

Friend has a custom Bell on his boxer it sounds great as revs increase, not overly loud, just a very nice pitch.

 

Image Unavailable, Please Login Got my new precat bypass pipes, can't wait to install ~$1K U.S. for the pair.

 

Please forgive a minor criticism, but they shouldn't have installed the thermocouple bungs as having the thermocouples mounted there will detect nothing and only be a flow negative. When using precat bypass pipes, the thermocouples should be mounted in the thermocouple bungs at the exit area of the main cats (and if no main cats, too, the thermocouples shouldn't be mounted in the exhaust stream at all).
You can note that on the official F TR precat bypass pipes, 142166 and 142167, that the thermocouple bungs are not present:
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I had those on my TR they made a great difference those Tubi ones, not as much as cat delete but at least the car didn’t smell
Bad. U will like them


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and if no cats then no thermocouples. they are only for preventing the cats to overheat

 

Those thermocouples are used for slow down right? They never worked great in mine!


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When eliminating the pre-cat, the O2 sensor is reading a ‘no cat’ mixture.

How does this affect the computer’s attempts to achieve an ideal mixture?

 

the O 2 sensor still measure and the computer is doing as if the cats where in. only thne range of the O 2 sensors may ve soemtimes out of limit and can not measure. but those O 2 sensors have nothing to do with the thermo couples

 

Without a pre-cat, the O2 sensor measures an oxygen rich mixture. Presumably, the computer then tries to add additional fuel to consume the excess oxygen.

Unfortunately, the additional fuel is based on the false reading and as a result, it overly enriches the mixture.

Can this overly rich mixture be adjusted and eliminated with the help of a gas analyzer?

 

when the O2 sensor measures a too rich mixture then the computer reduce fuel, not add.
what you understand under "rich mixture"? so lambda more than 1 or less?
if under 1 then the mixture is too rich, if more than 1 it is too lean

only during driving you can measure

 

The O2 sensor measures oxygen... nothing more. Lambda is determined in the computer by deductive reasoning, based on the measured level of oxygen.

When O2 levels are high, it deduces that there is insufficient fuel in the mixture to completely consume the 02. Hence, it adds more fuel.

Any way to compensate?

Am I missing something?

 

O2 sensor measures rest oxygen . right

still like to know what you understand under too rich:
so too much rest oxygen or less rest oxygen?
lambda more than 1 or less than 1

I think we habe problem with understanding/translation?

 

The ‘perfect’ mathematically, chemically correct amount of air and fuel results in all fuel and oxygen being consumed. This is called the stoichiometric ratio. Measured in mass (kg etc) it is 14.7 parts air to one part fuel. It is referenced as the air to fuel ratio or 14.7:1.

Lamda is also a ratio, but it is the ‘actual’ air fuel ratio divided by the stoichiometric value of 14.7:1.

Mathematically:
Lambda = (air actual / fuel actual) / (air Stoi / fuel Stoi)
Lambda = actual air to fuel ratio / 14.7

If your actual mixture has too much air, it is called ‘lean’. The O2 sensor sees excess O2 in the exhaust.

Mathematically, when lean, the actual air/fuel ratio goes up from the perfect 14.7:1.... say for example you have 16 kg air to 1 kg fuel or 16:1 ratio.

Lambda = (16 / 1) / (14.7 / 1)
Lambda = 16/14.7 = 1.08

Numbers higher than 1.0 indicate a lean condition.... Too much air, not enough fuel... O2 in the exhaust
Numbers lower than 1.0 indicate a rich condition.... Not enough air, too much fuel.... little or no O2 in the exhaust

Under load, most all engines do better with Lambda less than 1.... a rich condition. In the real world, Lambda should change with the varying driving conditions. Lean when it can (low load, steady state) and rich under load. The computers have an internal ‘map’ to adjust Lambda based on conditions (throttle position, revs, temp, knock detectors etc etc).

Back to the cat:
The pre cat burns O2 and fuel. The O2 sensor ‘expects’ to see the pre-mapped amount of O2 based on the pre-cat’s secondary burn.

Remove the secondary burn of the pre-cat and all of a sudden, the O2 sensor sees more O2. It thinks that the engine is running lean (not enough fuel to combine with all the O2) and the computer mapping injects more fuel.

At least.... that is the way I understand it. Correct me if I am wrong.

My question is this: in the Testarossa can the FI be adjusted to compensate for the new, higher levels of O2 when the pre-cat is removed?

 

PS: when I said “oxygen rich mixture” I meant too much oxygen.... not too much fuel. It was not intended to say ‘rich’ as in a mixture with too much fuel. It was a confusing, dual use of the word ‘rich’.

 

Of course (but I'm unsure of the difference as I'm not sure just what reaction is going on inside the precat -- i.e., what platings are used -- three-way? two-way? something else? For example, the precat may only be doing something significant when the air injection system is operating during cold-running and a lot of extra O2 is present). I'd say that the stock US TR is the odd configuration with something (the precat) between the exhaust exiting the cylinder and the O2 sensor -- virtually every other "with Lambda" car is configured more like a US TR with precat bypass pipes.

 

Hmmmm...
does that mean that simply turning a screw while watching the output from a 4 gas analyzer won’t do it?

or maybe....
yeah, it changes things, but compensating for the change is not practical nor significant.

or simply...
Fuhgettaboutit

or...
all the above


Sounds like a complex question that does not have a simple answer.