what do you guys do for a Y-pipe when swapping in an LT-1. i have the caddy LT-1 not a camaro, so i'm not sure if that changes things like.. the angle of the flanges n crap like that..

so far almost everything else has been slightly different between the two cars.. the 91 rs y-pipe has weird bends and doesn't line up so i've had to slice mine all to heck, and the tube is smaller than the lt-1 Y-pipe, i know this because i bought two flanges to bolt to the manifolds to weld to my y-pipe... i hate hacking things together, it will drastically screw up the flow characteristics.

they aren't the same, so i'm trying to find a cheap alternative.

has anyone used a stock 4th gen y-pipe on their car successfully?

does the cat mount in the same place give or take?

i took the cat out of my car a long time ago (smog friendly county) so that's not REALLY an issue, i just want to make sure it would go under the car far enough not to drag on speed bumps and crap like that.

----i cannot afford long tube headers and aftermkt y-pipe----- so that's not an option.

cheap cheap cheap cheap cheap options only...

like.. $10 junk yard options...

thx

 

Cheap alternative, bolt thirdgen manifolds and Y pipe up, done.

 

i sold my 305 with the manifolds on it, and i've already chopped my y-pipe all to crap to make it fit and started tacking it and decided i don't want to go that direction.

also, there's some kind of thing about round tubes and rectangular ports and things not matching up that i think has been talked about in a few of my other threads,

are you positive they fit and don't leak around the edges?

i mean......... are people doing that?

you respond to most of my posts, what did / do you do?

 

Yes i've done it and not had it leak, its not ideal for flow / performance by any stretch, but you asked for a cheap solution that works, i've done the swap multiple times and know what works.

 

I've never bothered to do it and try using 4th gen manifolds, not sure they'd clear the a/c box, and other than the first time I did the swap, a/c was the smart way to go.

Shorty headers and Y pipe are the best route IMO, but like I said it can be done using manifolds if you need to drive the car, the set I used were from an L69 being the best flowing manifolds and Y pipe offered on a thirdgen, headers werent in the budget for the person it was for at the time.

 

If the manifolds clear the a/c box and you get the Y pipe to a 4th gen, you could cut it up and make it work, but its not just going to bolt up as-is.

 

cool man.. thanks as always..

what i meant by the comment was

you obviously do this a lot and know what your talking about so what do you do in my situation, which... you answered adequately in subsequent posts...

hmm... so....

friend of my dad's has about a dozen of these old cars in his private junk yard (3rd gen), i texted him to see if he can call him in the morning and see if he has one that has long tube or shorties and a y pipe under one of the hoods he'll sell me, or if not, then stock manifolds and Y-pipe for...... i think L69 was 83-88?

You told me L69 for a reason and i'm learning as i go, so i'll ask: i assume the l69 manifolds have better flow char. than the 89-92 motors?

i keep thinking in terms of the fact that i have a 91, but that doesn't matter since the original manifolds when i sold it.... eeehhh... and of course knowing now that i can use stock manifolds, yeah.. im kicking myself in the butt for chopping my pipe up. but it's not beyond re-welding. that's just... not ideal, hence why i'm looking into other options to begin with.. if i wanted to re-weld the y-pipe to make it fit 3rd gen manifolds, i may as well weld them to fit the current ones.

but barring a few options, it seems like i'm going to have to hack and weld -something- regardless of what i use, or, settle for sub par flow characteristics. or.. well maybe not sub par, but you know what i mean.


as for the AC box not fitting by the LT-1 manifolds, see, that poses other questions and the reason i've been shying away from buying a g4 Y to stick on here.

I have a caddy motor, the manifolds that are on it now have plenty of clearance to the AC box and everything else. it all fits absolutely perfectly... and you and other people have mentioned the ac box problem here and on other forums, and i think the majority of people put camaro or vette LT-1's in their cars not caddy motors... so given that logic, it leads me to believe that the manifolds are different between caddy n cam/vette, and that a g4 cam Y probably won't fit to the caddy manifolds anyway.

so that saves me a bit of money time and hassle right there on what may be a safe assumption? i mean so far ////almost//// everything has been the same from caddy to camaro motor, but.. the differences are just enough to cause a few major annoyances and a lot of hair pulling. and.. tons n tons of brick walls. After doing this a few times i'm sure it gets to be common sense.

if i ever decide to do this again, i'll use a camaro LT-1, pay you to build the harness, and won't have nearly as many issues lol..

 

If the manifolds you have clear the a/c box, and you feel up to building a Y pipe then its not a bad choice for the time being.

The L69 was the biggest/best flowing setup factory, the only downside is that the Y pipe to catalytic uses an odd rectangular 4 bolt flange, but I used the entire manifolds, y pipe, hollow cat, and exhaust pipe, at the time I did the conversion using that stuff I was working at thirdgenparts.com, and had access to pretty much every stock configuration in short order, it was good enough to hold the car over till we got some shortys on it.

 

hmm.... yeah....

you know, i may just need to get a length of pipe tomorrow and bend myself a new Y-pipe using the flanges i bought for the LT. just makes the most sense, and a $20 piece of pipe, vs a ton of hassle locating any of the other stuff we're talking about and an increasingly shorter deadline to finish this thing.

definitely not opposed to fabbing something. and as you know, it's easier to fab something from scratch sometimes than to hack something together that doesn't quite fit...

I've got a mig a tig an arc and a pipe bender.... apparently i've forgotten this in my quest for trying to do things the easy way.

i've just really been trying not to have to do that unless there are no other options. it's really hard to do all of that stuff when the car is a foot and a half off the ground and you're holding a stinger in one hand, balancing the pipe off of your forehead, holding it up with your other hand, welding slag burning into your skin, jacket catching on fire, hood falling off your face, getting road grime in your eyes etc..

so many reasons i prefer to work on bikes -_- sigh.....

lol...

with that said................ i'm definitely going to attempt to track down some L69 stuff, that really does seem like the best temporary or... hell.. maybe permanent option. like i've said before, i'm not looking for a drag racer, just something that not everyone has with a potential for being hot rodded by........ probably the next owner.

yeah.... that's how i'm going to look at it for now on... "what do i need to do to get the platform ready / running for someone ELSE to sink all their money into it to make it high performance" lol....

 

You arent likely to sell it for a profit, I only suggest the stock manifolds as a good temporary fix to get the car to move.

Upgrading to headers is a HUGE performance gain on that engine, so I wouldnt put too much into making stock stuff work.

 

eeh.. yeh.... what are these cars worth with LT-1's in them anyway?

 

with fresh paint, a clean install, new rims and tires clean interior, nicely put together.. on average
$$

 

Not really a KBB input for such a thing, but thirdgens arent one of the cars where you are likely to build it up and sell it for more than you have into it.

I think in general add up everything you've got into it, then subtract 20-50%

 

Tough to find L69 specific parts sometimes & Since the TPI exhaust manifolds and Y are the exact same size (except cat connection and AIR pipes) look for TPI stuff if you want the stock look; it will be MUCH easier to find TPI exhaust parts rather then L69 parts.

False; TPI manifolds are the same size as L69 parts,.... & only TPI cars included the duel cat, or 'best flowing" Y pipe.

+1

 

First off "TPI" stuff you are referring to is wrong, yes there are some TPI's with the dual cats, this wasnt on all, nor nearly all of them.

2nd, iirc the actual ports on the manifold for the head flange were larger, and were the closest to fully covering the LT1's D ports.

 

Also, you want to call the dual cat setup the "best flowing Y pipe"

Maybe best flowing cat converters, however chances are an L69 setup isnt going to have the converter in tact, we're back to same size tubes (i could have sworn the manifold to Y tubes were bigger on the L69 piece, but i digress) with a similar merge, 6, half dozen.

 

No disrespect, but I'll only believe that one when shown irrefutable proof.

Car's with the factory duel Cat systems were the "best flowing",..... they happen to be TPI only. Since the L69 never got them, those manfolds are not part of the "best flowing" system. Since the L69 manifold and the TPI manifold flanges are exactly the same size, a duel cat Y-Pipe would bolt right onto L69 manifolds. THE POINT IS,........ TPI parts are the same size (IMO apparently ) & simply easier to find then L69 parts.


Never said it was.......

IMO the only thing that will properly seal a LT1 port is a 1/34",.... but I digress.


+ 1 more time.

 

interesting....

very interesting....

on another note...... next Tuesday a friend of my stepfather is supposed to bring a 4gen Y pipe to his shop, i understand i'm going to have to chop it up, and, i honestly don't expect the angles to be the same on the manifolds but... it will at least get me in the right direction and will be the appropriate size anyway.

i'll chop it up and make it work.

the guy is giving it to me for free, so i really can't complain!

I figured a lot of the other issues out that i had too over the last day or two like... radiator hoses.. well kinda. the driver's side hose that goes to the top of the radiator, if you get the one for the LT1 camaro, it'll fit if you cut a few inches off. i'm not opposed to that.

the bottom one from the 4th gen definitely doesn't fit. too short. but vaguely the right shape, so can figure it out from there.