HT4100 4.1, 4.5, 4.9 Discussion, 4.9 performance in Cadillac Engine Discussion; Hello everyone... Let's try and keep this thread only related to performance mods to the 4.9 I know there are ...
- 05-21-03 05:49 PM #1
Hello everyone... Let's try and keep this thread only related to performance mods to the 4.9
I know there are differnt chips... super chips has one for $250 that says it adds 18hp and 28ft. lbs. tourqe, and fast chips has one for $160 that claims 13-15hp.... which is better?
besides exhaust, what else is there? any cold air intake? not too much parts though, or so it seems (hopefully with the bigger crowd putting 4.9's in Feiros, someone will make something) but without tearing down the engine, and completly reworking it, is there anything that could be done?
I am really interested in those chips though, as they are (considerably) cheap, and seem to add a nice amount of power, but which is better?
- 06-02-03 03:59 PM #2Cadillac Owners Fanatic
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- Feb 2003
Personally, I'm skeptical of the claims of chipmakers. Other than raising the speed limiter, I don't believe the claims are accurate unless you're willing to sacrifice driveability, longevity or emissions.
For what reason (other than those above) would Cadillac detune their engines? Also, keep in mind that the 4.x engines don't have knock sensors, so detonation (and its associated damage) is a real possibility.
From what I've heard, you can accomplish just about anything a chip would do by running premium unleaded exclusively (and the same brand at all times for consistency) then manually advancing the base timing (by loosening and rotating the distributor) a couple of degrees. However, you're sacrificing reliability if you go on a long trip or get a bad tank of gas if it starts pinging and if you travel where environmental conditions are different enough from where you set the timing, you could have issues.
There's very little "tune-ability" in the efi systems on these vehicles. They are speed-density, which means they rely heavily on the physical dimensions of the engine in their EFI calculations. Yes, they adapt for temperature and outside air pressure, and they will fine-tune the mixture via the o2 sensor(s), however there's little you can do to get really serious change in output unless you can get inside that chip and customize the mappings to suit your situation. If you can do that, you open the door to a huge amount of possibilities.
You can make slight adjustments to the fuel pressure by replacing or altering the regulator. You could also make sure the TPS is adjusted properly and get some new injectors, but that's really about it and the increase would be negligible
One other alternative would be to run an aftermarket EFI system. Though not cheap, you could then build off that base and go in all sorts of directions - up to the limit of the transaxle, which is a whole 'nuther issue...
Of course, getting your body computer to talk to an aftermarket ecm/pcm is even less do-able than reprogramming the original ECM, so you'd need some sort of piggyback arrangement (or a hack) to get your onboard systems to function, and forget the onboard diagnostics altogether.
You could also hack in another, more tuneable GM ECM (like that out of the V8 truck and/or Camaro/Fbird). There are quite a few guys burning chips for that ECM. Same issues with interoperability as the aftermarket. but its a cheaper way to go.
If you decide to go down this route (performance mods), one good investment would be one of those G-tech meters. "Seat of the pants" performance evaluation is less than useless. You need hard numbers and the best (and safest) place to get them is at the track.
I don't mean any of this as discouragement, and I'd love to be proven wrong by some hard before/after numbers. This is more of a summary of my investigation of what it would take to go down this same path. Don't fall into the ricer trap of believing that just because it "looks fast" that it is fast. Do your homework and get some empirical data to evaluate the results.
- 06-02-03 05:15 PM #3
hmmm..... so basically your saying there is not much that can be done?
I was thinking, get that computer chip, try out a custom CAI, and after the car is paid off, get a nice cat-back Flow Master dual exhaust with medium diameter chrome tips (1 on each side in the back) that will look nice, and give the V8 the growl it needs..... I am thinking between those things, I may get like 30-35hp?
I was also thinking along the lines of a high performance cam, or rocker arms etc... I guess the only other thing would be to have a machine shop custom build it up....
.... then again a '93 DeVille isn't really the car to hot rod out..... I want to get 3 cars in my life (fun cars, not dailey drivers) 1 is a '70 Chevelle SS (mmmmmm 454) other is a late 70's DeVille with the 500 (make a huge sleeper outta it, just crazy) and the last would be a Grand National.
- 06-02-03 07:17 PM #4
If you think that no performance gains can be found strictly through ECM/PCM tuning, you have a lot to learn sir. True, some of the things you'll do MAY compromise the MPG but that's about it. The emissions will be Ok and driveability can actually be improved upon a lot. At the risk of repeating myself, I would suggest talking to Ed Wright at FastChip and he WILL set you straight on what CAN and CAN'T be done with your ECM.
- 06-02-03 10:41 PM #5
Well, I am saying kinda simple things...... reprograming the ECU seems like it is very time consuming, costs alotta money, requires gear I don't have, and very hard to come by. I am not saying it can't be done, I am just saying, as I was reading it, it seemed very difficult.
- 06-03-03 07:03 AM #6Cadillac Owners Fanatic
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- Feb 2003
I didn't say that ECM tuning was completely ineffective. I said you could accomplish the same thing by raising the base timing. A generic one-size-fits-all 4.9 chip is not going to do much more for you. If its custom-calibrated for specific modifications you've made, that's a different story.
Here's what I base my ECM comment on, as well as a good part of the rest of my comments. These are posts from a GM Powertrain engineer who frequents the Allantenet board. He was involved in the Allante and 4.1/4.5/4.9 engines as well as Northstar development. (Sorry, its a long post) Chips and performance mods have been a topic several times. 4.1 and 4.5 engines are essentially the same as 4.9s:
(This particular thread is about one of those "20+ hp chips on e-bay, but the discussion wanders into ECM chips in general"
"For the record...."chips" don't make power...more airflow thru the engine makes more power and the computer calibration cannot create more airflow (unless you have a turbo-charged engine and the computer is limiting boost....and/or you have a diesel....but that's another story)
If the engine has been modified with cam, heads, intake, etc....then the computer calibration will need to be modified to account for the increased airflow but the hardware mods are what is responsible for the power increase....not the calibration mods.
While there may be some engines some where that are not calibrated for the optimum performance at WOT I would say that the vast majority of them are. There is no emission nor government constraint on the fuel and spark delivered at full throttle so there is no reason, especially on a performance car engine, for the manufacturer to "hold back" on the power.
I can positively state for a fact that the Northstar engine is calibrated for maximum pwer with the factory calibration and there is no way on earth a "chip" is going to make more power. Adding or subtracting fuel or spark is not going to do anything but slow it down.
The 4.1 and 4.5 engines are just a trifle "soft" on the spark calibration to account for the fact that the engines did not have a knock sensor but no chip change is required to compensate for this. Just set the timing at the distributor up 2 or 3 degrees and run good gas and you are all set. Send the $5.00 to your favorite charity.
The item advertised on e-bay is a joke. It is just a simple resister to replace the Inlet Air Temp (IAT) or Manifold Air Temp (MAT) sensor. This will accomplish nothing except screw up the fuel calibration and make the engine drive poorly on coldstarts as it will no longer have active MAT compensation. This is an old trick that has been used for many years on a variety of fuel injection systems as a means of altering the fuel delivery curve for various reasons.
It is possible for a specific set of modifications to the engine to use the MAT substitution as a means of compensation and, in fact, it works quite well to put a variable resistance pot in place of the MAT if you are using the car for drag racing or some limited driveability use with a heavily modified engine but for an engine driven daily with no other mods the idea of gaining power by putting a resister in place of the MAT is ludicrous.
I don't think there are as many "compromises" in the factory ECM calibrations as some might imagine when the engine is operating at WOT. Many of the "chips" will turn off the knock control, for example, and then tell you you have to use only high octane gas.but you would get the same result if you used the high octane fuel with the factory calibration....to prevent detonation so the knock control system wouldn't have to retard the spark to protect the engine. The good gas is what made the power, not the "chip" that now compromises the protection of the engine. Another trick is to turn off the EGR....but the factory calibration turns off the EGR at WOT anyway. The chip without EGR will "feel" better at part throttle...but who cares about part throttle power...you are throttling the engine anyway. If you hold the throttle wide open the EGR will be disabled with the factory "chip" for free. Another trick is to delay the apply of the TCC....once again, makes the car feel better at part throttle...but, once again, the factory cal does that at WOT anyway. AC causing Hp loss, chip gets rid of it...???...the facotry cal turns off the AC compressor at WOT automatically for a short period of time so there is no need for this mod. The list goes on and on...and....there is no way the aftermarket "chips" are going to make more power.
One feature of the Northstar engine is the fact that the factory calibration runs at the optimum fueling level (actually on the rich limit of optimum) for about 30 seconds and then the calibration goes richer for protection of the piston crowns (temp) , to prevent the spark plug tips from getting too hot and inducing preignition and to protect the catalytic converter from overheating. If the engine is run at a sustained full throttle condition in about 5 minutes it will get rich enough to actually loose about 2-3 percent torque.... This feature could be eliminated in a "chip" to limit the torque loss at sustained full throttle but, you'll be buying pistons later if you run it at sustained full throttle.
This will cause some controversy, I'm sure, but the fact is that the chips sold to improve the performance of the engines rarely if ever do anything but compromise the driveability , emissions and engine protection. "
(This thread is specifically about an '89 with a 4.5)
"The 4.5 engine is like any other engine and will respond to the same modifications....unfortunately there are two obstacles....one is that there are little or no aftermarket parts available for the 4.5 engine....and, two, the engine has a speed density fuel injection system that does not react favorably to things that change the airflow thru the engine....and you must get more airflow to make more power.
Some simple things that help a little without seriously affecting the fuel injection calibration....
Get the exhaust backpressure down...go to a low restriction muffler/larger pipes/dual exhaust from the catconv back/etc.
Bump the ignition timing up several degrees. The 4.5 does not have a knock sensor so the spark calibration is on the conservative side to avoid serious damage to the engine if less than good fuel is used. If you always use premium or better the engine can benefit from an extra 3 or 4 degrees of spark. Just bump it up and drive. If you hear detonation or pinging then back it down a degree until the detonation is gone. Tune it to "top dead ping" as we laughingly call it. Nothing will be hurt if yo are reasonably carefull and use good fuel. Just always listen for detonation if yo buy unknown fuel.
Bumping up the timing is as easy as just resetting the distributor timing with a timing light.
If you really want to take the engine apart you can get the lower intake manifold and/or cylinder head ports ExtrudeHoned to smooth the surface finish and increase flow.
If the heads are off you can deck the heads about 1 mm to get more compression.
Other than having a custom cam ground or other special parts made this is the easy stuff.
If you can find someone who can reprogram the ECM chip you can find a 4.9 and plug the parts from the 4.9 into your block and have a 4.9 litre displacement instead of the 4.5 ..... nothing beats cubic inches. If you did do the 4.9 conversion (which mechanically is very doable) it will run poorly unless the ECM is reprogrammed ot recognize the extra displacement ....or....you could do a crude compensation by going to an adjustable fuel pressure regulator and bumping the pressure up 9 percent to roughly equal the 9 percent displacement increase."
"Leave the catcon in place and do the Borla or Corsa cat-back system. The cat does not hurt the power at all with an exhaust system installed.
Bump the ignition timing up a few degrees and leave the ignition system alone.
The air induction system on your engine has plenty of capacity for anything you're going to do.
Forget the chip. The factory chip has the correct fuel and spark values for maximum power. The only "soft spot" in the production chip is the spark calibration as I mentioned...it is a few degrees short of max power to give some cushion for poor fuel. You can correct this with bumping the timing up and making sure you always have good fuel. An aftermarket "performance chip" would do the same thing and require you to run good fuel anyway so just bump the timing up and save yourself some money."
- 06-03-03 08:03 AM #7
While I agree with most of what was said in that other thread about the use of ECM/PCM mods to attain better performance, I would add the following points that were overlooked:
1. Doing ECM/PCM mods may net minimal WOT performance gains but the part-throttle driveability is where the HUGE difference can be attained.
2. ALL fuel programs that I have seen are a little fat from the OEM and there is some room for improvement that CAN be made (and verified) through the use of wide-band O2's and a dyno.
3. Even though the spark and fuel tables in the program are pretty good from the factory, the trans shift tables are generally quite able to yield big gains in both overall driveability and 0-60 times as well as 1/4 E/T's.
- 06-05-03 10:47 AM #8Cadillac Owners Fanatic
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- Feb 2003
Have you actually experienced this on a 4.x engine/transaxle? I'm not doubting you, but I find it hard to believe you can make changes to that drivetrain with a chip that come anywhere near justifying $160, much less $250. What is the driveability difference?
I'm just wondering what a chip can possibly do that would exceed the stock setup when its properly tuned. A lot of the power is already wasted because you can already easily overwhelm the traction of the drivetrain (either with wheelspin or with the TCS intervening), any attempts to launch harder just transfer the weight off the front wheels. If you bump up the timing, you risk uncontrolled detonation. If you lean out the fuel, you can make things really bad. Airflow is pretty much fixed.
I guess I don't really question that changes are possible with a chip, as much as I question that a chip that can be dropped into a stock vehicle, or one without very specific modifications, can really deliver anything of value, or anything that can't be accomplished with some minor adjustments outside of the ECM.
Also, a 4.9 is already putting more torque through the 440t4 or 4t60 than any other GM engine it was attached to. I'm not sure playing with the shifting without beefing things up is wise, but that's just a hunch on my part.
Anyhow, I hope this doesn't come across as skepticism, its intended to be inquisitive.
- 06-05-03 01:39 PM #9
I have limited seat time on the 4.x stuff to be honest. The lion's share of my time has been on the LT1-powered stuff and some of the Northstar stuff. Overall, the theory is sound and quite reasonable to relate to virtually all engine management systems.
You're right that there's not as much that can be done with ECM's as can be done with PCM's (drop-in chip vs. re-flash), but that's why I suggested Ed Wright as an information source. He has FAR more experience than I and can DEFINATELY describe what can and can't be done on a particular system.
Even if you didn't do anything to the spark and fuel tables, you can still get a great improvement in driveability from playing with the trans tables.
I personally got a MUCH more enjoyable car to drive and one that accelerates better as evidenced by my time slips at the track. Each time I went down, I had a new flash to try and all but once netted an improvement in my E/T's.
Downshift/upshift points, shift firmness, converter lock-up points. All these are places where the OEM program is lacking for the performance minded driver. Remember, these cars weren't really setup for performance, they were setup for SMOOTH cruising, and the best MPG they could get.
As for your point about off the line traction, you're absolutely right but the modifications I suggest in the programming would have little or no effect on that.
Perfect example would be; on my car, I bumped the 2-3 shift up a little and kept the converter off until 50mph on my first or second flash and it made a big difference in both E/T at the track and driveability around town. I've since played with other stuff but you get the idea. You can realy custom tailor the trans "personality" to your driving style and that makes a huge difference in the satisfaction factor while driving.
As for the torque to the transaxle issue, I wouldn't be concerned to much unless you start doing part swaps on the car and start REALLY increasing the engine output. I don't agree that you can't make power with just a reprogram of the engine management system but, I do agree that you won't make much. The trans work has nothing to do with power increases, but everything to do with what you do with the power.
- 06-10-03 11:20 PM #10
man i missed this place, i kinda gave up on my deVille after the hit and run, BUT i have a new found love for it, so she'll be getting fixed soon. anyway, i dont know much about the EFI system on the 4.xs, but say if you bumped up the displacement from, like 4.5 to 5.0 couldnt a chip help compansate and tell the ECM to send more fuel? oh and what about after the heads and intake beign ported and the exust, could the chip help with that too?
- 06-17-03 09:30 AM #11Cadillac Owners Fanatic
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- Feb 2003
Re: 4.9 performanceOriginally Posted by Panther
I'm particularly thinking of the PFI or TPI (Allante) engines. One of the nitrous companies makes a setup for 5.0 mustangs where you insert a fuel/nitrous injector below your stock injector (the stock injector is placed inside the nitrous/fuel injector). It raises the fuel rails up a bit, but that probably isn't a problem. These systems only work at WOT, so you're not limited by the ECM. Also, since the nitrous system has fuel as well, you don't have to worry about going to lean. If memory serves, they have a way to retard the timing, or you retard it all the time, I can't remember.
I don't know if I'd try nitrous with a throttle body 4.9, unless I was plumbing in individual fuel/nitrous injectors.
I can't say for sure it would work, but it might be worth looking into if you're serious about getting more power. Additionally, with the nitrous systems you can usually tune them for the amount of boost you want, so you only have to buy the system once, then as you make upgrades (to the transaxle!) you can increase the nitrous shot.
Here's NOS's piggyback system http://www.holley.com/HiOctn/ProdLin...NS/NOSzle.html
From that page:
"Horsepower levels up to 150HP are possible with stock fuel systems and internal engine components. Higher levels require upgrades such as forged pistons and stand alone fuel systems. "
I did a quick search and found a company that carries the universal V8 system. It's around $1600.
Something to think about.
- 06-20-03 01:40 AM #12
If you want a FAST Caddy you need to buy a Road Rocket like Katshot drives with the Chevy LT1 RWD, Then you will have the Best of both worlds >Luxury and Performance All in One car!
- 06-20-03 07:42 AM #13
Re: 4.9 performance
I'll go for that
- 06-20-03 11:01 AM #14
no, I am not going to put NOS or any nitrus....not in this car.
I know a car witht he LT1 and RWD would be awesome, but I don't have that, and just thinking of ways to get better performance from what I do have.
- 06-20-03 12:33 PM #15
Re: 4.9 performance
Whatever path you choose with your car, just realize that the stock engine/transaxle package WILL NOT handle a significant power increase without SERIOUSLY shortening it's service life. At least the LT1 in stock trim has the basic ability to be a solid foundation for a performance car whereas the Cadillac V8's do not.
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