: Curious about performance mods...



NeverLLac'n
11-25-05, 10:01 AM
Hey, i'm new to this cadillacforums, but i thought it would be a good way to get ideas and information about my car. So, yeah, i've got a 1998 Cadillac DeVille, obviously the 32V Northstar is in it. I've put a hurtin' on a couple mustang gt's, :lildevil:. they have plenty of horsepower obviously, i was quite tickled with it when i first drove the car. Anyway, on to the questions,,,, i was wondering if there were any good sites, or bullshit like that where i could find performance parts for my northstar, and i also wondered if anyone had the information on these engines stock, horsepower, torque, and so on,,, any information would be much appreciated!

Seth

Hason560
11-26-05, 12:10 PM
you really should use the serch option and search these forums, but if ppl start to post here i guess ill chime in with my opions, exspect a heated debate though!! lol just a warning

NeverLLac'n
11-27-05, 01:04 PM
Yeah, so i've done plenty of searching, and obviously if i want to mod. a car, i should get rid of the deville. Hmmm.

Exhaust and filter is about the only thing i can buy, that is definately shitty!

Ranger
11-27-05, 05:24 PM
That's not shitty. What it is telling you is that the factory already picked all the low hanging fruit for you. As a former well respected member who was very knowledgable about the Northstar put it, "GM left nothing on the table". It already puts out 1 hp per CID. How many Stangs do that?

Hason560
11-28-05, 12:31 AM
rangers right that gm did pick alot of the low hanging fruit and produced a hell of an engine but dont get discouraged, this one real answer to the whole question. money!! if youve got it it can happen what ever it may be! i hate how everyone on here say cant this and never that but in actuallity it CAN be done with money and a want to do it. just my rant sorry, im just really sick of everyone telling me modding the northstar is pointless.

NeverLLac'n
11-28-05, 09:52 AM
Oh yeah fellas, there is no doubt that the northstar is one hell of an engine! I mean, my car weighs in at an even two tons, which isn't TOO much, but it's definately no jap trap. I've put two mustang to shame thus far, one is a 94 mustang gt, and the other was a 96 gt, both 5sp, and both had exhaust, ya know nothing crazy, both are fairly weak, but it's still really nice watching the video, and saying bye bye to the overpopulated ford POS. Haha, okay i'll quit ranting about that now.
I would like cams for my car, P/P heads, and full exhaust, and if there were somewhere to buy that kind of thing for the N*, that would be wonderful. But i really appreciate you all's input anyhow.

SupaStealth
11-29-05, 01:37 PM
Eh, i'm not sure about the whole "GM left nothing on the table",they did in terms of leaving no room for aftermarket. ....eh i just deleted most of my post, because this is just going to be a repetitive cycle that nobody wants to hear :p

Frost
11-29-05, 01:54 PM
go to chrfab.com - don't forget to bring your cheque book and whatever you do, don't lose your pen!

,,,,,then get in, sit down, turn the key and shut up,,,,,,

Hason560
11-29-05, 07:06 PM
amen to that my brother

danbuc
11-29-05, 09:42 PM
The camshafts from CHRFab will not really work in your car. Mechanically, they will operate and run the vehicle, but that's abotu it. Aside from throwing codes and what not, those cams move your tourqe too far up in the power band, which only slows you down even more off the line. I have personally spoken with CHRFab on this matter a year ago, because I was inquiring abotu the same thing.

Other than a free flowing exhaust system, a higher stall speed torque converter will also inprove your off the line acceleration and response. A good stall speed for these cars without descreasing drivability, is around 2800-3200rpm. This will get the engine into it's peak power more quickly, therefor making more of use of it when you launch the car.

The OEM paper filter is pretty much the best thing you can use for your car. It will flow all the air that the engine can use. K&N (or similar) filters do nothing for the northstar, other than move your tourqe further up the rpm range making it less usable, and flow more dirt through.

Porting and polishing the heads will only really benefit you if you are using forced induction (i.e. Turbocharger, Supercharger,..ect). You also only want to polish the exhaust side as well. To be honest, unless your going all out with the modifications, it's more trouble than it's worth.

eldorado1
11-29-05, 10:00 PM
an 80mm throttle body was getting 20hp on the 4.0 auroras. 4.6L should benefit more.. (keep in mind both engines use the same 75mm TB stock)

NeverLLac'n
11-29-05, 10:29 PM
Danbuc, you're talking about getting a stall convertor for the car, but i have a 98 deville, FWD obviously, and i wasn't ever aware they made larder convertors for my car. Where can i find these??

zonie77
11-29-05, 11:49 PM
Here's one of Mark's posts. Look at his page on his Caddy.

http://www.cadillacforums.com/forums/showthread.php?t=57750

danbuc
11-30-05, 02:32 AM
The Converter that Mark got was from Yank http://www.converter.cc/ . That 80mm throttle body from RSM racing isn't worth the money it cost to ship. Just look at Mark's page. He has one, and even he said that he didn't think it did a damn thing for his car. Just changing the size of the throttle body isn't going to help anyway. A change of 5mm is nothing. People also forget that the diameter of the T/B opening, and the diameter of the spacer and Intake Manifold are all matched to about the same size from the Manufacturer. Simply changing the T/B to a larger opening, isn't going to change the diameter of the spacer and INtake manifold. Not only that, but now your creating a restriction in the air path, that will only slow down the air as it goes from the larger T/B opening, to the small factory diamter opening in the spacer, and intake manifold. The same thing happens when you buy an aftermarket intake manifold, and don't port the cylinder heads accordingly. You create a point at which the air hit's a right angle and this slows it down.

As far as the converter goes, it's not so much the fact that's it's larger, it's the relationship between the Turbine and stator assembly. The Converter that Mark bought (if I'm not mistaken) is a modified OEM converter. In most cases, thsi is how they are made. The factory OEM converter is dismantled into it's seperate components, and is then changed accordingly, so that it will perform as expected.

The driveability isn't affected all that much either. Although the aftermarket high-performance/ high-stall speed converters slip, so do the OEM converters. Some converters like the 3600rpm stall speed converter that Mark has slip more than the OEM ones, which is why he installed a seperate trans cooler. Lower stall speed converters like the 2800rpm converter he orignially had installed in the car, are not as extreme, and therfor behave more liek that of the OEM converter. The main difference is where the actually begins to stall (or lock up). A higher stall speed converter will allow the engine to rev higher into it's power band, before locking up, and turning the wheels. This means that the car is not so much making more power, but using what it already has more efficiently. The car now launches with more power off the line.

danbuc
11-30-05, 02:37 AM
I think I should also mention that other engine mounts are available. WHen I had to replace the front engine mount in my car, I opted to go with the RSM racing billet aluminum one. For startes, the thing will never wear out or break liek the OEm hydraulic mounts will. Second, aside from a very slight increase in engine vibration transfer to the wheel (not much more than what would be considered normal) I have much better response from the car when I mash my foot to the floor. The reason is, that unlike the hydraulic mount, the aluminum doesn't give, so there is no lag from when the engine rock on the mount, to when it actually transfers the power to the wheels. This rocking motion is what usually causes the early demise of so many front engine mounts, particularly in the Sevilles. This is most often the result of someone with a heavy foot, who likes to get on the gas every once in a while.

eldorado1
11-30-05, 10:49 AM
That 80mm throttle body from RSM racing isn't worth the money it cost to ship. Just look at Mark's page. He has one, and even he said that he didn't think it did a damn thing for his car. Just changing the size of the throttle body isn't going to help anyway. A change of 5mm is nothing. People also forget that the diameter of the T/B opening, and the diameter of the spacer and Intake Manifold are all matched to about the same size from the Manufacturer.

Time to whip out some math.

(37.5mm^2)*pi = 4417.9mm^2
(40.0mm^2)*pi = 5026.5mm^2

That equals 13.8% more flow over stock, supporting (in theory) 341 HP. 5mm is a LOT. The spacer is the same size as stock, 75mm, but it too can be bored out, and I think RSM does that service as well for an extra fee. The intake manifold is about 78-80mm (last I checked it was kind of an oval), but it probably wouldn't be worth while to open it up. The 20hp on the 4.0 I'm talking about is with the bored spacer. If you don't bore the spacer, it IS worthless.

mcowden sent me a datalog a while back of a 275hp northstar, and it was showing significant restriction in the upper RPM range. 300hp northstar would be worse, because they've got the same intake as everyone else.

MARK99STS
11-30-05, 04:21 PM
Time to whip out some math.
(37.5mm^2)*pi = 4417.9mm^2
(40.0mm^2)*pi = 5026.5mm^2
That equals 13.8% more flow over stock, supporting (in theory) 341 HP. 5mm is a LOT. The spacer is the same size as stock, 75mm, but it too can be bored out, and I think RSM does that service as well for an extra fee. The intake manifold is about 78-80mm (last I checked it was kind of an oval), but it probably wouldn't be worth while to open it up. The 20hp on the 4.0 I'm talking about is with the bored spacer. If you don't bore the spacer, it IS worthless.
mcowden sent me a datalog a while back of a 275hp northstar, and it was showing significant restriction in the upper RPM range. 300hp northstar would be worse, because they've got the same intake as everyone else.
You are right in theory and yes I had the spacer and the intake manifold bored to match the TB(all done by RSM). This was all done after my exhaust and intake mods so I didn't see much change. The problem that nobody really address is the crossover/down pipe from the front bank. This is the choke point of the motor. You can open up the intake and port the heads, but if you don't mod that pipe, you won't see any additional gains. Don't get me wrong, the Corsa exhaust made a big difference, but that's all you get unless you modify the front of the exhaust system. I have learned this by trial and error.

eldorado1
11-30-05, 04:38 PM
did you take it to the track before and after? dyno?

People will argue with me, but the butt-dyno can't detect a 20hp change.

MARK99STS
11-30-05, 04:50 PM
The Converter that Mark bought (if I'm not mistaken) is a modified OEM converter.

Actually according to Yank, the SS3600 is a new converter with more fins and designed to have the drivability of a 2800 but launch of a 3600.

MARK99STS
11-30-05, 04:55 PM
did you take it to the track before and after? dyno?

People will argue with me, but the butt-dyno can't detect a 20hp change.



Yes I did take it to the track before and after the mods from RSM and was actually surprised that there was no difference. I called them and they also were shocked that I saw no gain. So I don't know. Maybe it is just my motor with slight differences. I know this car was faster than other STS' that I drove before buying this one.

eldorado1
11-30-05, 04:58 PM
Stock intake and AC Delco filter?

MARK99STS
11-30-05, 05:04 PM
Stock intake and AC Delco filter?


No. K&N cone filter with all stock ripped out. See my list of mods.

http://www.markonemtg.com/marks99sts/

eldorado1
11-30-05, 05:06 PM
wow, that's really surprising then!

Maybe you've hit the limits of PCM compensation.

MARK99STS
11-30-05, 05:12 PM
Thats a very good point and a very good posibility. That is why I am going the turbo route.

danbuc
11-30-05, 05:12 PM
Actually according to Yank, the SS3600 is a new converter with more fins and designed to have the drivability of a 2800 but launch of a 3600.

That's nice to see, that they engineered it to be more efficient. Some of the other manufactures don't put as much time and effort into their converters, which is a real shame. I know you said that when you had the 2800rpm stall speed converter, that you didn't really see any decrease in driveability which was good.

Just out of curiosity Mark, what was the turnaround time on the LSD build from Engineered Performance?

Also, hows the turbo coming along. Have you gotten all the quirks worked out of the piggy back system yet? It'll be interesting to see how all of it comes together and functions as a whole when your all done.

MARK99STS
11-30-05, 05:21 PM
The turnaround for the LSD was about 2 1/2 monthes. But this was the prototype. Hopefuly he could turn one much quicker since he has done one now.

We are starting on the turbo this weekend, so I will keep everybody posted. Unfortunately it will go slow as we will have to do a lot of frabrication and modifying. The piggyback is working fine being able to control AFR which is what we were after.

Gotta sign off for now.

Later