| Author | Message | ||
| Mitchel DeFrancis (4re308)
Member Username: 4re308 Post Number: 523 Registered: 6-2001 |
I'll stick a word in here for Franklin Parker. I was behind his 348 Spider in a 3.2 Mondial with a Tubi on a mountain drive, and MAN OH MAN his car sounds glorious!! Looks so nice in silver too. | ||
| Craig Dewey (Craigfl)
Member Username: Craigfl Post Number: 369 Registered: 1-2001 |
These are pipes that directly replace the catalytic converters. Since it is illegal in most states to remove or modify emission control equipment, these pipes are marketed as "test pipes" to test your car without the converter - but not to be left on permanently. Some of us forget to change back though....  | ||
| William Henderson (Billh)
New member Username: Billh Post Number: 2 Registered: 5-2002 |
maybe someone can explain to me. what are the "test pipes"? I thought these were a bank of small 1/4" pipes that connect to your exhaust system for measuring pressure drops accross the cats. some cars have these removed. it seems like the term is used here to describe replacement pipes for when cats are removed. are these the "test pipes"? | ||
| Mark (Markg)
Junior Member Username: Markg Post Number: 189 Registered: 2-2001 |
I'm not putting mine on so much for sound/power, but rather to drop trunk temperature. Anything else is pure gravy ... | ||
| Frank Parker (Parkerfe)
Member Username: Parkerfe Post Number: 840 Registered: 9-2001 |
I have test pipes on my 348 Spider and noticed a lot of difference in acceleration. It sounds much better too. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1258 Registered: 2-2001 |
You can check the intake vacuum with a gauge. It should be about the same at 3000 rpm as it is at idle. If it drops too much there is probably a converter blockage. The sure fire way is to remove them and look through them to see if light will pass through. Also if one of the cats should clog the corresponding exhaust manifold will glow red hot. You could also use an infrared thermometer to compare exhaust temps. | ||
| tCoupe (Allen)
New member Username: Allen Post Number: 40 Registered: 3-2001 |
I'm going to try the test pipes soon but first--- Sounds like a good thread to ask this question: Does anyone know what tests I can perform to determine if the "Cats" are bad? Still trying to resolve the intermittent "Slow-Down" light issue on both banks. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1254 Registered: 2-2001 |
By all means hook up the O2 sensor as this will allow the computer to go closed loop after warm up and give better fuel control and mileage. | ||
| Frank Parker (Parkerfe)
Member Username: Parkerfe Post Number: 825 Registered: 9-2001 |
DrTommy, you need to hook up your O2 sensor even with the cats removed. The test pipes on my 348 have a fitting for both the O2 sensor and the thermal coupler. Your engine management system thinks you are running too lean and is dumping more fuel in which is causing you to run too rich. That's why you're getting all those fumes. If your test pipe doesn't have a fitting, you can drill a hole and weld the correct size nut over the hole to accept the O2 sensor. | ||
| John J Stecher (Jjstecher)
Junior Member Username: Jjstecher Post Number: 196 Registered: 1-2002 |
Tim-35hp is not too optimistic....I looked back at the dyno numbers and I am assuming a 21% loss in the tranny. This car also had a ANSA exhaust on it so I was wrong in my first post about being nothing else besides cats and K&N. Davehanda is correct there is a much bigger difference in taking a K&N and putting it on a carbed car versus a FI one...the MAF reads more air entering the system then compensates by adding more fuel, thus more power when the mix is right...thus is shows us the importance of making sure your oxygen sensor is in good shape! Dr Tommy - My guess as to what the balls of fire are is unburnt fuel getting forced out the exhaust valves under heavy decelleration it then ignites when it hits a hot part in the exhaust. | ||
| BretM (Bretm)
Advanced Member Username: Bretm Post Number: 2529 Registered: 2-2001 |
I love the smell of exhaust in the morning. I have found both the Ferrari and Jeep (neither has much in the way of emissions, or anything for that matter) smell a little when cold, but when they warm up are fine. | ||
| Dr Tommy Cosgrove (Vwalfa4re)
Junior Member Username: Vwalfa4re Post Number: 122 Registered: 5-2001 |
Ed-what do you think this flame thing is? It's just a quick flash upon deceleration after running it hard. The car runs great otherwise. | ||
| James H. (Jamesh)
Junior Member Username: Jamesh Post Number: 54 Registered: 5-2001 |
I have heard the stock Cats are very restrictive and a good custom exhaust shop can install an aftermaket cat that is less restrictive. Tommy, you should have your car checked, I dont think balls of fire should be shooting out your exhaust just because you took out the cats. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1251 Registered: 2-2001 |
I too am considering reinstalling them due to the pollution and fumes. Cats really work! | ||
| Dr Tommy Cosgrove (Vwalfa4re)
Junior Member Username: Vwalfa4re Post Number: 121 Registered: 5-2001 |
My cat has been off my car for 2 years. It has a tubi also. The sound is great and very different then the Tubi and the cat. My problem is the fumes. It has almost made me re-install the cat several times. I still may. I let a friend drive it once while I followed in my Alfa with the top down. We got stuck at a long light and the Ferrari was actually making my eyes burn after a couple of minutes. On the track I even shoot balls of flame from the pipes. Does this smell thing bother anyone else with this setup or does the smell/flame throwing combo mean I am just running way too rich? (my O2 sensor is NOT hooked up) | ||
| Tim N (Timn88)
Member Username: Timn88 Post Number: 835 Registered: 6-2001 |
35hp for removing the cats on a 348 seems a bit optimistic, unless maybe the original cats were clogged. | ||
| Brent Lachelt (Brent_lachelt)
New member Username: Brent_lachelt Post Number: 2 Registered: 4-2002 |
Mark, Thanks for the info. I'll be anxious to hear what the car is like when you get them on. Let me know, OK? Thanks, Brent | ||
| david handa (Davehanda)
Junior Member Username: Davehanda Post Number: 96 Registered: 5-2001 |
Just wanted to chime in here. I think the difference with/without cats and K&N is different between carb and FI cars. With FI the air flow sensor can compensate for the increased flow and provide more fuel, with carb, you will likely end up lean until you richen your jetting. On my 78 308 GTS I installed a K&N, Nick's ss test pipes, and removed the belt on my airpump. Now I did not dyno before, but after, my car was showing only 160 hp at the wheels, and exhaust emissions were VERY lean. Upped the stock 125 mains to 140's and the the car was now making 178 hp at the wheels, which is about 214 hp at the crank. Stock for a 78 308 is 205 hp. Friend with 83 308 QV installed Tubi w/o cat, and K&N and makes 200hp at the crank, which is about 241hp at the wheels (stock is 230hp) with no other adjustments. Just my experience/observations.... | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1242 Registered: 2-2001 |
The people with GM cars are having to periodicly remove their MAFs and spay carb cleaner on the wire to remove all the crud so their car will run OK. | ||
| Scott Grossman (Sngsmgaolcom)
New member Username: Sngsmgaolcom Post Number: 30 Registered: 2-2002 |
Ed, I dont know about 308's, but my TR's PCV vent is into the rear of my airbox, and if that oily blowby hasn't screwed up my MAF, I dont think the airflow from the K&N is going to do any harm. Scott | ||
| Mark (Markg)
Junior Member Username: Markg Post Number: 183 Registered: 2-2001 |
Brent L.: I also have an 82 GTSi, bought (but received wrong) test pipes, waiting for correct ones now (FI cats are 16-1/4" long; carb are 13" long). I found removing the Cats to be a pain, you will need very short wrenches and and angled wrench, all 13mm. | ||
| Ben Lobenstein 90 TR (Benjet)
Member Username: Benjet Post Number: 576 Registered: 1-2001 |
Bill, M.ass A.ir F.low sensor, if I'm not mistaken. -Ben | ||
| BretM (Bretm)
Intermediate Member Username: Bretm Post Number: 2497 Registered: 2-2001 |
I figure at the rate that the damn car needs to have the engine pulled I could be running friggin velocity stacks with no filters and just rebuild when the engine is out for something else. | ||
| Bill Sebestyen (Bill308)
Junior Member Username: Bill308 Post Number: 203 Registered: 5-2001 |
Edward, What is MAF? | ||
| Doug Meredith (Doug308)
Junior Member Username: Doug308 Post Number: 149 Registered: 2-2001 |
When I had my 308 QV, I did dynos 1 week apart with the original Cat and with the test pipe. The gains were 1.5 HP and 1.8 FtLbs increase. The chart curves were identical. When I sold the car, the dyno charts went to the new owner so I no longer have them. My opinion: Better sound, lighter, and saves the original $1000+ CAT for emissions testing. However, there was a lot more mid RPM resonance in the car (which some may not like), and the fumes from the unburnt gas from the tailpipes will creep into the cabin at stoplights. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1234 Registered: 2-2001 |
I removed the cats on my 308 and while the numbers stated may be true as for dyno testing there was little if any actual seat of the pants feel of additional power other than it was louder. On late model GM cars removing the cats shows no additional HP gains on a dyno probably due to the fact that they are of a superior design. I stand by my performance air filter claims. They are screwing up MAFs with dirt and oil and it only tells me that the dirt and crap that didn't get caught in the MAF went somewhere. | ||
| John J Stecher (Jjstecher)
Junior Member Username: Jjstecher Post Number: 195 Registered: 1-2002 |
On a 348 removing the cats gives you around 35hp on the dyno with a K&N installed. Thats not to bad for $400 for all the parts...whats that compare to $2K+ for a Tubi which will give you less over all power gain. To me if you live in a state which doesnt require testing and want more power out of your car those are the two mods I would make. | ||
| John J Stecher (Jjstecher)
Junior Member Username: Jjstecher Post Number: 194 Registered: 1-2002 |
Edward - I hate to tell you you are wrong but adding a test pipe does add probably the most amount of hp for the buck. Everyone thinks that just adding a Tubi is the end all in performance mods for an exhaust system, what everyone forgets is that all you are doing is making the cat a larger bottle neck than it is in the first place. I have dynoed my fair share of cars and can tell you that taking a set of cats off will usually add more hp than replacing the whole exhaust system aft of them. Also for those of you non-believers in K&N filters giving you a boost in hp look at Rob Lays dyno numbers for his 328, he made 10 more rear wheel horses with the K&N vs stock....thats saying something! Plus K&N's filter MORE not less particles than their leading competitors (FRAM, and so forth) | ||
| Brent Lachelt (Brent_lachelt)
New member Username: Brent_lachelt Post Number: 1 Registered: 4-2002 |
I have a 1982 308 GTSI. Are the test pipes from Nick Forza's pretty easy to install. My mechanic says it will give it a deeper sound. Does it really sound better? | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1222 Registered: 2-2001 |
It sounds to me as if you should leave well enough alone. | ||
| Barry Wolinsky (308gtb)
Junior Member Username: 308gtb Post Number: 73 Registered: 2-2002 |
Thanks Ed and Bret. Just wondering. I'm pretty happy with what I have now. A conventional filter is in place. I have an Ansa muffler installed (the original is in my garage) and the sound is just right. Not too loud and I can hear the carbs breathing over the exhaust sound during acceleration. The carburettors are all in synch and the engine runs smoothly. It even pulls up well from 1500 RPM in 5th. I can't ask for much more | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1218 Registered: 2-2001 |
I personally do not believe in these low restriction filters. When you lower the restriction you also allow larger particles of contaminents into the intake. It may be small but the power increase is small too. I again ask would you use a lower restriction oil filter to gain a miniscule amount of power? I didn't think so. | ||
| BretM (Bretm)
Intermediate Member Username: Bretm Post Number: 2495 Registered: 2-2001 |
You don't have a mass airflow sensor Barry so it wouldn't do anything. I've never heard of anyone have to, but the worst case would be a couple quick carb adjustments. I have K&N on the QV which is significantly more prone to something like this, and I have had no problems. | ||
| Barry Wolinsky (308gtb)
Junior Member Username: 308gtb Post Number: 71 Registered: 2-2002 |
Ed, I have a 1976 non-cat, carburetted 308 GTB. Would the K&N air filter be OK? | ||
| BretM (Bretm)
Intermediate Member Username: Bretm Post Number: 2493 Registered: 2-2001 |
As far as cat less power increase, minimal like Edward said. Not enough to really make a difference alone in any acceleration, track times, etc, but it is a good start for performance mods. The sound though without them is a thousand times better IMO. It may be too loud in some cases (not for me) but it is beautiful. Pulling the cats out of everything is good. I knock all the material out of my Jeep cat the other weekend (small exhaust leak where the air injection system goes into the cat, obviously the air injection system is no longer in my car after this). Now the jeep starts up with a little brappp, tap the gas quick and you get it, pin it to the floor and open up the second barrel of the weber and the sound is great. I'm surprised how burly it sounds, I can't imagine there being any overlap in the exhaust and intake of the jeep valves. I'm pro good sounding cars and I guess anti-emissions, at least on cool cars. | ||
| James H. (Jamesh)
New member Username: Jamesh Post Number: 47 Registered: 5-2001 |
Actually I think my car is too loud now, hard to hold a conversation while driving. Where is a good place to order a KN filter. | ||
| Edward Gault (Irfgt)
Intermediate Member Username: Irfgt Post Number: 1216 Registered: 2-2001 |
It will probably add a small amount, but in most instances the additional sound is more a psycological thing versus an actual performance gain as is the installation of performance air filters. The air filters are really screwing up the cars with Mass airflow sensors. | ||
| James H. (Jamesh)
New member Username: Jamesh Post Number: 46 Registered: 5-2001 |
Does it really add performance by replacing the cats. with the test pipe on a 328 |