This is why I recommended you do a 224 on a 114+2 or You could even do a 115+2 LSA. With your stall and gears the 112 LSA 224/224 is just going to sound rougher and it will be less efficient in the area you can't use anyway with your stall so it won't be any faster but the wider LSA will be much more efficient everywhere you want it to be and believe me it will play better with your cats then the 112 LSA, a lot better

 

Ok, that makes sense. This is my first stalled auto. I was amazed at how much the stall improved the performance of stock motor when I put it in.

 

Not bad at all. Yeah, I think despite my lack of mods and being an M6, if I went the race path like everyone else I would have much improved my times but I wasn't interested. I just drove it straight in off the street and ran it. That being my point, despite M6 being tricky to launch, I was much faster than some of the big cam auto cars on Drag radials and had only ever raced once before (where I ran a best of 12.9 in the same trim with bolt ons). I used to outdo the bigger cam cars on independent dyno days too, actually. My car was very well tuned though. Things have also changed a lot in recent years. I still get shocked by the US GTO times I see for the power they make.

 

Basically no one runs without cats here on street cars. Fines are too big and shops test this and find you don't lose anything on regular cars running with high flow cats, I know US guys say otherwise though. We have cars in the 9s still running cats down here.

 

Lots of variation, huge to small nowadays, depending on what someone wants from their combo. Transmission type plays a part as well. Lots of Manual Monaro cars sold. Crow Cams and VCM cams seem the most popular brands from what I've seen. When I purchased my Cam Motion Cam, no one here had ever heard of them, lol.

 

Quite possibly, although one has to ask, how hard is a modern auto car to run down the 1/4? I've had stalled V8s on race style tyres and they were simple to drive compared to a 6 speed like I have. Especially with a weak clutch, like my car. A bit more painful, lol

 

I've run a 12.9 in full street trim with the tired stock motor. Only mods were exhaust, stall and 3.46 diff. Hoping to give it a run before the rebuild now I've got 3.73 gears but I don't think my trans will let me. It doesn't like changing into 2nd at WOT any more.

 

Interestingly, not seen many people run the Harrop cams. I looked at them previously. I think they are made by a US vendor. Could be Cam Motion actually. Not sure.

 

No tune or intake? Impressive! Stalled auto paying off? I'm always surprised how many people with autos are afraid of a good stall converter, I loved mine on other cars I owned.

 

Yes tuned but stock intake. The convertor made a massive difference.

 

I've been thinking about what I would buy in your shoes if not importing a TSP cam. I think I would purchase a Crow Cam. They seem to be doing good things and I believe they now own all the CamTech equipment and designs. I think if I had your combo inc an auto with 3500 stall like you do, I would choose a Crow 222/230 .613/.612 114. Seems big on the exhaust compared to the 224/224 you mentioned but from what I've seen, it shouldn't have a huge affect on fuel use but will help power.

 

I'll check that one out as well. LSX Performance Parts sells the Crow and TSP cams and kits for a pretty good price here in Australia and likely cheaper than I can get one from the states. I've been quoted ~US$150 for delivery for just a cam from a couple of US suppliers.
They also have the TSP 224/228 which is another option.

 

I purchased my TSP Cam from LSX. Went well. I paid $700 though! So $575 is a good price. That TSP 224/228 .600 / .600 112 should be good for your combo.

Yes, I've stopped buying from the USA due to exchange rate and expensive global delivery costs. Shame because companies like Summit are fantastic to deal with.

 

Cheers, I've just sent them an email.

 

I spoke to my tuner today and he recommends the 224/228 over the 224/224 but suggested to go for 110lsa over the 112. He said from his experience the overall gains will outweigh the small loss at the top end.
I'm still undecided but it doesn't look like they do the 224/228 @110 anyway.

 

Way too much overlap for your cats,. People say the cats don't hurt power much and that's true on a stock engine but the more overlap you add the worse it gets. If you don't believe me get some V bands or whatever welded on your cats so you can swap them out for off-road pipes when you dyno Tune it

 

Can you elaborate in more detail how overlap interact with cats? 🐈

Where's the sweet spot 0 or less overlap?

Have had someone from a big name header company explain that their green cat, cat technology doesn't harm hp more than ~2 hp worse case in ~700+ hp applications. That seem hard to believe.

 

I experienced issues with a negative -5° overlap cam and catalytic converters.

Specs of the cam that caused my issues: 218/224 113lsa +3°

I have the "updated" version of the 3" TSP high flow catted y-pipe. Swapping out the catted pipe for the same style off-road y-pipe was worth about 3/10 of a second in the quarter mile on my car with no other changes, car went from mid to bottom 12s I have the time slips somewhere I can dig them out

I had that same camshaft lying around later and I threw it in my 2004 suburban with the stock manifolds catted y pipe and a higher flowing muffler. Tune is spot on, When it's hot outside above 85°, if you have to sit in the truck with the engine running and the AC on for more than about 15 or 20 minutes you'll notice that the temperature gauge has creeped past 220 and it will continue climbing until you get scared and turn the AC off.

Guess what happened to the truck when I put an off-road y-pipe on it. Yep it stopped getting hot during extended idle., It ran much better everywhere else. The cam is too big for the truck anyways so I'll be replacing it with something much smaller so I can keep the cats.

Overlap is like misfiring we all should know that by now. The dirtier your exhaust is at idle and low RPM (more unburned fuel) The more work the cats have to do and the hotter they get. The further downstream you can get them away from the headers the less they will hurt scavenging and power

Until holdner gets a whole bunch of cats together and tests them on the same engine with various valve timing etc You're not going to change my mind on this. Sure there are exceptions to every rule but any NA combination that needs a really good exhaust to work well is going to be hurt by them

 

I totally agree on the converter. I've had a 3200 Yank in my C5 since 2005. I bought my converter directly from Yank, and got the highest stall ratio they offered. I was told stall ratio affects how "tight" the converter feels, with the higher # being the tightest. Sure, you'll lose mileage around town (if that matters to you), and you'll need a better trans cooler than just the radiator. However, if you run a 3.73 or 3.90 gear (exact ratio may differ, but I think most know what I am saying), it will feel nearly stock. For sure run a lockup converter, unless you're building a drag only car. A converter is one of the first things an auto trans car owner should be changing on his or her car. The diff gear is the next. THEN start on the motor.

 

I get what your saying here, but at idle, the cats don’t do much anyway. They heat up, yes, but nothing like what they see at cruise, which is where cats are designed to operate at. This is why the EPA a is so so so big on cars in the US idleing less. Most everything new cuts off at idle now because of this. National Parks across the country have signage stating to “be our idol and please don’t idle”. Gas burners are dirtier at idle because the cats aren’t as hot. I would love to see testing on this as well. Meow.