so took my ls vtec eg to Hayward to get it dyno tuned yesterday and some weird stuff happened I'm hoping you guys can help me figure out what to do.

1. first it laid down a baseline of 176whp (not bad for stock gsr cams) then every run after that it kept dropping power without them doing anything till I left with 150whp was clear something was choking it as it kept getting quieter and quieter and not revving like it should

2. By the third run it was spitting tiny metal flakes out of the exhaust. They said my 4 day old high flow 2.5 catalytic converter melted. Their thoughts were that you can't really run a high flow cat on a built honda without melting it and that I should put in a straight pipe, which defeats the whole purpose of having a honda BAR'd.... I thought there were many people running high flow cats? any thoughts on why this happened?

3. Also, above 6k rpm my car blows out a good amount of oil smoke. It makes good power but I figure this has to either be rings or valve guide seals. any way to tell what is causing this without opening up the motor?

 

If you need a cat, contact snap.

How can you bar a ls-vtec?

 

you can't BAR a ls vtec but my BAR sticker just says legal for an Integra B series so the smog guy will just see the B on the block and I'm good to go.

I actually have another high flow cat but don't want to just melt it again and waste money on dyno time. any thoughts on why a brand new cat melted? maybe from oil coming out the exhaust?

 

If you had metal blowing out the exhaust - have you dropped the pan to see if there's any metal in there? or at least check the oil?

I'd say you're lucky if it's only a bad cat. Sucks, yes, but better than a ring & sling.

 

If the car was getting quieter and quieter it was definitely killing the cat.

That was the inside of the converter comig out of the exhaust.

Now as to why the cat could "Melt" or clog up.

If the car is running too rich, it will clog the catalys material causing excess fuel to burn in the cat and getting it so hot it cracks, or binds together causing no exhaust to exit the cat.

If your engine's valve seals are starting to go bad it will have oil blow by. Same withthe rings. This will cause the cat to clog up and get red hot and melt. I would run a test pipe for dyno purposes and when it gets BAR'd just put an oem or a high flow on it for the process.

If you are making decent power i wouldnt even bother running a catalytic converter. I Had no cat on my car for the whole 5 years i had it until it was stolen. **** even though i got it back the exhaust still has no cat on it.

I would just have both readily available.

 

If it started to rev slower, and get quieter.. and started spitting metal flakes, i'd look at your bearings..

 

sounds like rings (or maybe valve contact? -i've had it happen and not explode the piston) check your oil.

And as for your cat, why are you running one? yea i know the environment, but guess what if your car is tuned(i.e. increasing the fuel ratios) it pollutes! plus your going to keep clogging the cat because your now running richer than 14.7:1

Also if your car melts cats then it is a good sign that it doesn't want one.

 

thanks guys,

I know it melts the cat if its too rich but I told the tuner it had a new cat on it so would it then be his fault for letting it run too rich while on the dyno?

I would really prefer to just run a cat, I don't care much about the 4hp or whatever it will cost me since this is my commuter car. I already have other race cars.

I checked the oil and it looks fine.

any way to tell if its the rings or the valve seals without replacing them? If its the valve seals that is no biggie but if it needs new rings that is a different story entirely.

 

it can't be his fault for running it too rich as he didn't manufacture the cat or warranty it, what about the company that made it?

as for the cat, yea run it, but know that it is not meant to go on a car with below 14.7 to 1 afr. I'm not saying you cant run it, but get ready for your exhaust to get clogged every six months, i don't look at as a way to make power but a way to stop from losing it as it gets clogged as i too don't care much about gaining 4hp, but i do care about losing 20+ like in the beginning of this story.

Run a compression test then a leak-down test, between those two you should be able to make a guess as to what is going on.

 

lol, I was thinking how the engine spitting out metal flakes could be bearings. If metal flakes from engine bearings can make its way through the oiling system, then through the ring lands into the combustion chamber then out into the exhaust stream THEN through the catalyc converter, and out at the tail pipe, THAT"S some badass mother****ing metal flakes. To the op, just drop the cat and look inside of it, it's not your bearings cause if it is then your vtec wouldn't still engage due to loss of oil pressure.

 

Lol, that was funny.

 

hahaha.... I was thinking the same thing. If it was spitting metal from the bearings out the exhaust then it would have made some awesome noises on the dyno probably!


but if the tuner knew the car had a cat on it then why didn't he just run it at a different AFR that maybe made a little less hp but didn't ruin my car?

I don't know, maybe I'm totally wrong, but aren't there people on this board making decent power for many many miles and years through high flow cats?

I know a guy that put down 600rwhp in a super charged vette through some high flow cats so it seems like it should be doable on my honda but maybe that's not how its done?

 

one more thing:

If the rings were so bad that it was blowing out hella oil then wouldn't that also show up as a weaker motor? I am leaning towards it being valve guides most likely since the motor put down 176whp with basically no tuning through a cat and on stock gsr cams and stock b16 intake manifold. seems like pretty decent power for the setup to me and certainly healthy?

thanks guys

 

Remember, that's just numbers...not absolute proof of what your motor makes power wise compared to any other motor out there unless it was an SAE number at least.

 

Spitting bearing material out of the exhaust that had to first get through rings, combustion, exhaust valves, a cat, and a muffler - not to mention 15+ feet of piping? Hell would freeze over first.

How did you get the car to the tuner? A basemap he provided? I can't see any competent tuner that's been at it for a while running a 170-180 whp B-series setup too rich to melt a cat. The guy has probably seen hundreds of sub-200 whp B's. Looking at it from the surface,if the cat failed, I'd put it down to manufacturing issues until you can get more info.

 

LMAO . . . this made me laugh at work and the whole way home

 

I'm leaning towards just bashing out the inside of this cat so its a straight pipe and then putting it back on and getting it tuned and dealing with the cat issue another time. DNR knows their shiat so I also doubt he would run it so rich as to melt my cat. I know a dyno is just a number but 176whp with gsr cams, b16 intake manifold and through a cat and muffler seems strong on any dyno. I told them I didn't care about peak numbers also and DNR is legit so I doubt they tried to inflate the numbers.

I compression tested the motor and it was 230 even across all cylinders. Car idles smooth and runs strong. other than oil coming out the exhaust though. lol

So how do I tell if my smoke issue is from rings or valve guides?

 

I ask because if its valve guides, I can get an itr head tonight for $600 with supertech springs that is in good shape. If its rings though then I'll probably just leave it as is and get another shortblock and replace it this summer.

 

Could you elaborate how bearing material gets spit out of the exhaust? Im confused...

 

Your smoking at 6k rpms and above may be caused by inadequate crankcase ventilation. What kinda crank ventilation setup do you have?

 

interesting point and you could be right, hadn't thought of that since my build is pretty mild.

I don't have any real crank case ventilation other than the tube off the valve cover that goes to the intake. I think with a b18b block though there is no vent for the bottom end?

 

im curious as to what the story is behind the motor. how many miles on it? if it was consuming oil or not before the dyno run. you mentioned
oil smoke, so you can say yourself it was a blueish color? after a new cat or straight pipe, i would take the car out and drive it up to 7k and let the engine decelerate the car to check for oil getting past the valves. then go out on the freeway and put the car under a full throttle load to check for bad rings ( oil control rings specifically) i.e. have a friend drive behind and monitor the exhaust coming out the tail pipe. i would expect the worst and hope for the best. you might have two problems coinciding at one time, hopefully not but you'll soon find out.

 

Actually, i was just giving a first hand experince.. on my old itr motor... i was on a lunch break with some friends and we were romping on it alittle...keep in mind i had just changed the oil the day before. Car was fine..but at lunch it didnt rev as fast as it normally does....i didnt think anything of it, just chalked it up to being hot...it was like 98ish.. anyway got on it on the way home and it was slower and quieter...half way home, went to take off from a light like normal and got rod knock..


just because you have never heard of it doesnt mean ****...ima laugh if this guys motor goes to **** if you dont least check it...

 

also, why not drop the exhaust and find out if it is infact your cat or piping..while at the dyno...
at least get that out the way...find out if it is a cat or motor issuse....metal flakes could be alot of ****...pieces of pistons, rings, cyl walls, or parts of ur cat....just giving out ideas. its really not about being right or an *******... but trying to help this guy out..

 

That is what I think also.