: Performance questions!!!!

03-08-05, 09:11 PM
hey guys.
on the 99 STS. I have corsa exhaust system, and it didnt really sound too much like what the exhaust tones they put on thier websites...but the power gains were def. noticeable.
i had dynomax mufflers, and personally i thought they sucked...too low and it made the noise sound like it was coming from the engine rather than the rear....BLAH!!!

so i get a dynomax hi flow universal 2.5inch cat installed, and lemme tell you...not only does this sucker get louder...but it sounds totally similar to the corsa website tones...i think this is what they did to achieve the sound...the Hi flow i noticed also gave me more power/torque..thats for damn sure...I LOVE IT!!! and no SES code.

my ques. is. will the RSM TB throw a code? and will it fit to the stock airbox's inlet tube???

also i checked out the cadillac fabricators website...looks like they are working on headers for our cars...pretty sweet.
also has anyone tuned a 99 or newer STS at all?
i think id be interested in getting minor tuning..nothing crazy


03-08-05, 09:57 PM
The soudn on the Corsa website is a recording, and nto a very high quality one at that. That is why it sounds a little different.

CHRFAB does make header for the Northstar, but unless your driving a Sand Rail, they're not gonna fit. They don't sell any product for actuall Cadillac Cars, but only for the Northstar engine. None of their products will work properly when install in a car anyway.

You can't tune the ECM, with out investing thousands of dollars in equipment. People have been trying to hack into it for years, but with no success.

The RSM throttle body is not worth the couple hundred bucks it costs to buy.

I suggest you call Yank and ask them about purchasing a High Stall Torque Converter. That, along with the exhaust, and maybe an LSD are the onyl real mods worth th money.

03-08-05, 10:19 PM
So the TB wont quicken the throttle response in the least bit? i figured with my pretty much straight threw exhaust, it would work nicely...although they are just numbers, they claim 14hp...i figured a good 10hp wouldnt be too bad...my only next option would be just porting and polishing it myself...but im too lazy...LOL.

the higher stall converter i was thinking about...but then u crack into the tranny, and those high stall converters stater usually breaks after a while, and arent usually as good and strong as the stockers.something i wouldnt wanna deal with again!

the LSD sounds sweet, and would def strengthen the tranny, as long as its done right....sometimes the casings on these suckers crack b.c theyve been hollowed too much to fit more springs...but i thought the caddy spins both tires from the line anyways??
my main concern would be the input shaft..anyone cryogenically freeze any yet...its cheaper than the 4340 metal input shafts, im sure no one makes them for this 4t80e anyways.

i was interested in the rear and front strut tower bars along with the rsm tranny mounts. i had stiffer tranny mounts on my older car...it was nice.
its a shame this motor is so complicated for performance..im afraid of over doing it , i dont wanna break shit...thats y basic bolt on without Codes would be great.
lets pray that company makes some headers real soon

03-08-05, 11:27 PM
Just what do you think "headers" are going to do for you? The N* already has tubular "header" type manifolds as it is. The bottleneck is in the pipe that snakes around and under the engine/trans. W/o changing that, and that means running the downpipe around one side or the other. No small feat.

03-09-05, 12:01 AM
The throttle body may make a small difference, but you would also have to widen the plate it mounts too. It's not really worth the $250 or what ever it cost though.

The high stall torque converters from yank are very strong, as they make most of them expressly for drag racing purposes, and therefor must be rather strong.

The LSD from engineering performance, is not a modified stock diff, but was designed to be one from the start. That company make LSD's for pretty much all FWD GM cars.

I was thinking about the tranny moutn that RSM has, but those struts bars, would really only be worth it, if you were going to autocross with your car. These cars already handle quite well, they just need a little more ooomph in the straight line department if you know what I mean.

03-09-05, 01:36 AM
Nice replys DanBuc.
you ghave me itching on the LSD . nice to know its not a stock modified.
After the torque converter crap i been through with Pro Torque, and other big names...im still leary. and dont wanna go through that .

according to cadillac fabricators, the headers will make a huge diff, they told me over the phone. they are currently using a STS to develop them on before going into production, and after 3 years they already outgrew thier facility, and plan on growing further. along with STS modifications, and told me to periodically check thier site time to time on new mods.
The headers no matter what will allow better airflow.
those tubular manifolds are horrible. the best could be extrudehoning them...but thats way expensive.
with headers, cadillac fabricators told me they are designing them in such a way that there will be clearance, but a tight fit. fine by me. just as long as it fits.
They also said, they are working with GM divisions on how to Tune them also.

03-09-05, 02:44 AM
I spoke with them about a year ago regarding headers for the cars, and they said at the time, they were thinking about it. Seems that they have started work which is nice. I have the website for Engineered Performance here some where...her it is. http://www.engineered.net/eplsd.htm . They don't have the 4T80E listed on their site, but when I spoke with the guys over at Domestic Performance, they said that they also make one for it, since they are somewhat similar in design.

Here is the website for Yank converters also, if you want to check it out. When I spoke with them, they new I had an STS, as soon as I mentioned I had a caddy. They said they have built quite a few, and have had really good results with them. http://www.converter.cc/home.htm .

Mark99STS over on the caddyinfo forum, ran a 14.1 in the 1/4 with a 2800rpm converter, a set of slick, and the RSM throttle body. He did say however, that he qeustioned the contribution the throttle body actually made though. He also has the Corsa exhaust like me. I've been trying to save up for an LSD, and a 3200rpm stall converter, but between my crappy job, and school, I don't seem to have the money I thought I would at this point in time. I guess it'll have to wait for summer.

03-10-05, 10:44 PM
Question about the Corsa's, I was tempted to buy a Northstar car just because of the way it sounded with those pipes.:holycrap: What did all that cost and do they drone?

03-10-05, 10:49 PM
I don't have any drone at normal cruising speeds on highway, or regular streets. It gets pretty loud when you hammer on it though. I purchased mine directly from Corsa, for about a little over $1,000 if I remember correctly. My friend at my local Meineke ( I think that's how you spell it?) installed it for about $90. I got in in January of '04, and I've been extremely happy with it. I get alot of comment on it, from people at my school. They are always asking me what kind it is, and saying how cool it sounds when I roar past them on the highway going home from school. :D

03-11-05, 05:48 AM
yea id say pretty much everything Dan says . my corsa rocks, and i got a 2.5uin hi flow cat that enhanced the sound also and made it more throatier, power gains are excellent as well. no drone either.
i got mine on a christmas sale. 900 dollars shipped.

03-11-05, 10:00 AM
What is the cheapest cat back exhaust system available for the 1993 Cadillac Seville STS? I would like a high flow cat and good mufflers. The only system I have heard any good talk about is the corsa. Are there other more price worthy exhaust systems out there?