99 Eldorado, new to forum, have ?

[nefferoo]

i am new to the cadillac world along with new to forums and was just wondering what performance options are available to the 99 eldorado? such as intake and exhaust....any help would be appreciated

[BodybyFisher]

Welcome, there are very few if any performance modifications, we used to have the designer here and he made the statement "all of the low hanging fruit has been picked", any further gains will require big$$ outlays. That said, the bottle neck in this engine is the exhaust crossover pipe, but there is no solution to that problem.

You might let it breath a little better by opening the exhaust up and using performance mufflers.

Keep in mind that this is a 279 cu in engine that is putting out 275 and 300 HP stock. That is pretty amazing as it stands. I think that making sure all of the ignition parts (plugs, wires, coils, etc) are in good shape and that all vacuum hoses are intact would keep it running strong.

[kev2]

the Northstar has LOTS of power,

I would first advise against the marketed easy HP promises (problem makers) , things like "tornado, Fuel line magnets, K&N, spitfirefire, Converter elem" same idea -seperate you from your money.

First suggeston would be to get EVERYTHING running operating to spec, especially fuel pressure- exhaust back pressure, then as you are required to replace the worn damaged parts that do not meet spec do your home work - get suggestions "NOT ADVERTISEMENT" and replace with items that may be improvements over OEM/stock.

ALSO we live in a world of emission testing and computer controls ... can't fool them.

[nefferoo]

would an intake even be possible for my car to make it breathe better? and is their a programmer or pcm swap that can be done in oder to change the stock settings and to get rid of the speed governor? lastly what mufflers would you recommend and how would i go about openng up the exhaust?

[JasonA]

No intakes are produced for these cars, and some of us who have made our own (myself included) have gone back to stock. In the case of these cars, they really were designed right, from the factory. There is no PCM tuner available to remove the speed limiter. The limiter is based on the original tires. If you have a base Eldorado, it came with S-rated tires, and the limiter is about 112 MPH. ETCs came stock with H-rated tires, and a 130 MPH limiter. Some ETCs had Z-rated tires, and came without a speed limiter. Rumor has it this setting can be changed by a dealership with a tool, but nobody's going to accept the liability to change it for you.

Someone on the other Cadillac forum site (www.cadillacforums.com) has tuned the OE PCM with some success (to include removing the speed limiter). I believe he can only work on a few model year ranges.

A good pair of mufflers are going to be your best bet in terms of anything you can do.

You CAN also install the 3.71 final drive out of an STS or ETC. If you have the base Eldorado or ESC, you have a 3.11 final drive, which is rather tall. A shorter final drive (like the 3.71s) will better your acceleration. This would also involve a PCM setting change, so you'll need to find someone who can tune the PCM.

[Cadillac Jim]

I would recommend that you put stainless steel turbo mufflers on first. Then, if you can hear your cat hiss at WOT at the top of the RPM range, your cat may be slightly clogged and you can change that too (get an aftermarket one at a muffler shop and avoid the rather amazing dealer prices for cats). At that point you can decide what to do; I would stop at that because anything further amounts to experimentation that you may end up reversing, with time and money lost. This is pretty much where I am. I need the car every day and can't afford to experiment.

One thing that *probably* does not involve reprogramming the PCM is changing the intake cams to the VIN 9 cams. This will move you from 275 hp to 300 hp, but it will move your torque peak up a couple of hundred RPM and drop it from 300 lb-ft to 295 lb-ft. This will require new lifters, assembly lube, and a break-in period of about 500 miles of running at under 3000 RPM, and it may not be possible with the engine in the car. This engine is sold with the 3.71 axle ratio and you will still have the 3.11 axle ratio, a 19% difference -- which is very considerable. You will find things a little slow at the bottom end of low gear but you will have amazing performance from 30 mph up for a non-ETC. If you change the rear axle ratio, I would just move over to an ETC programming for the PCM because the drivetrain will be all ETC at that point.

[TDK]

Nefferoo,

I noted some of the following before, but I believe its all still relevant:

You may want to search on "Marks STS". I have not heard much lately, but he had some great 1/4-mile times - even before he quasi-isolated the PCM and installed a turbo. He also switch-bypassed the traction control. I think they mentioned about $12,000 to get it all done and it was a LOT of work.

I believe opening up the exhaust is still the best bang for the buck (it will be louder...).

Keeping the weight down to improve acceleration is simple and it always works.

If you were to change the gear ratio as noted above, and also install a high stall speed converter to get the RPM's up into range for launch - you will have done as much as practical to launch quickest. It will probably need the traction control tweaked and tires optimized soon after that.

Stay away from heavy tire rims (bad physics to get rolling) and remember that as the rims go bigger, there is less sidewall to absorb road impacts. 20's look cool until parking into a little curb, ruins 'em.

I don't think that NOS, throttle body spacers, turbos etc - work with the engine management computer. If the engine is gutted and installed on a sand rail with all new, minimal hardware and software, then the "Sky's the limit".

Some believe in revising the air inlet and others have shown that this area is not the bottleneck. There are also some aftermarket air inlet lits that provide poorer filtering, tend to swallow water easier and the sensors don't work as well such that the engine actually runs worse. Unlike the exhaust, more noise at the inlet - does not always mean more power.

However, regarding whatever bolt-on equipment you might buy, do the decals included in the box look cool?

Good Luck !

[BodybyFisher]

Nefferoo,

I noted some of the following before, but I believe its all still relevant:

You may want to search on "Marks STS". I have not heard much lately, but he had some great 1/4-mile times - even before he quasi-isolated the PCM and installed a turbo. He also switch-bypassed the traction control. I think they mentioned about $12,000 to get it all done and it was a LOT of work.

I believe opening up the exhaust is still the best bang for the buck (it will be louder...).

Keeping the weight down to improve acceleration is simple and it always works.

If you were to change the gear ratio as noted above, and also install a high stall speed converter to get the RPM's up into range for launch - you will have done as much as practical to launch quickest. It will probably need the traction control tweaked and tires optimized soon after that.

Stay away from heavy tire rims (bad physics to get rolling) and remember that as the rims go bigger, there is less sidewall to absorb road impacts. 20's look cool until parking into a little curb, ruins 'em.

I don't think that NOS, throttle body spacers, turbos etc - work with the engine management computer. If the engine is gutted and installed on a sand rail with all new, minimal hardware and software, then the "Sky's the limit".

Some believe in revising the air inlet and others have shown that this area is not the bottleneck. There are also some aftermarket air inlet lits that provide poorer filtering, tend to swallow water easier and the sensors don't work as well such that the engine actually runs worse. Unlike the exhaust, more noise at the inlet - does not always mean more power.

However, regarding whatever bolt-on equipment you might buy, do the decals included in the box look cool?

Good Luck !

I was going to link to Mark's site but it seems his site for the car is down. I have not seen him lately, I know he was involved with residential mortgages so I am sure he has been impacted by the national mortgage problems and that has his attention..

But yes, Mark is an example as to what can be done, but I know that he spent a boatload of money, AND.... while the car was radical, it was not very driveable as an everyday driver, I think he said, it was a handful. Didnt he up it to 500 HP? See this site http://caddyinfo.ipbhost.com/index.php?sho...c=10602&hl= and this > http://caddyinfo.ipbhost.com/index.php?sho...ic=8837&hl=

[nefferoo]

ok thanx alot for all the help and info..

[JasonA]

One thing that *probably* does not involve reprogramming the PCM is changing the intake cams to the VIN 9 cams. This will move you from 275 hp to 300 hp, but it will move your torque peak up a couple of hundred RPM and drop it from 300 lb-ft to 295 lb-ft. This will require new lifters, assembly lube, and a break-in period of about 500 miles of running at under 3000 RPM, and it may not be possible with the engine in the car. This engine is sold with the 3.71 axle ratio and you will still have the 3.11 axle ratio, a 19% difference -- which is very considerable. You will find things a little slow at the bottom end of low gear but you will have amazing performance from 30 mph up for a non-ETC.

I wouldn't put the L37 cams in without also changing the axle ratio. The absense of low-end torque combined with the Bonneville gearing will make for a slower machine, not faster. Note that the L37 engine was NEVER paired with anything other than the 3.71 gears. The LD8 was initially paired only with the 3.11s, but was available in the Bonneville GXP with the 3.71 final drive. The performance of that car was actually very much right on-par with STSes and ETCs. The gearing makes the real difference -- the difference in cams is just a horsepower numbers game.

Our prior resident Northstar guru was asked about this before (adding the L37 cams to get the 25 horses in an LD8 car). He said it just doesn't work right. They tried different things at the factory and the L37 engine is a pig when paired with the 3.11 final drive. They had to use the 3.71 gears for that reason -- there's no torque with the L37.

Someone on the other Cadillac board put 3.71 gears into his DHS (275 hp engine) and was outrunning DTSes (in 1/4 mile times). The better torque characteristics of the LD8 engine combined with the better response of the 3.71 gears really does provide the best of both worlds. I've thought about switching my intake cams to LD8 cams. I'd get the big torque increase and still have the 3.71 gears.