D-1SC installed!

[Gauger]

I would jack that rev limiter up. You don't want to hit that while in boost.

Why would that be an issue? Doesn't the rev limiter just cut spark? If so, then he wouldn't run lean, so no danger.

The reason they make blower cams is because NA cams have a very big overlap and you lose alot of boost/a/f mixture. If you put Blower cams in there You would make alot more power.

I hear this song and dance very frequently, and I don't buy it at all. Now, the overlap bleeding off boost makes sense, but I have two responses to that. First, both Tripoli and I have "N/A cams" (more accurately described as having a lot of overlap) and both of us made more boost than we intended and more than people told us we would make. Perhaps we're the oddballs, but this argument doesn't seem to hold water despite the fact that it makes good sense. Second, regardless of whether Tripoli's high overlap cams are bleeding off some boost, he's clearly making plenty at 9psi even with the belt slipping some.

I've read a very well-documented article where a company took two or three pairs of motors (all 4.6 mod motors to my recollection) and measured their power N/A and boosted. In every single case the motor that made more power N/A made more power boosted as well. I'm pretty sure that in all the tests, the only major difference between the motors was the cam profiles. The end conclusion, which seemed to be very solid, was that regardless of what crackpot theories you might come across, the motor that makes more power N/A will make more power under boost.

My car isn't a freak by any means, but it made a pretty healthy amount of power for what was done to it when it was N/A. Relative to other LS1s with similar mods, it was fairly significantly above average, but definitely not the best. I attribute this mostly to the cam choice. Anyway, after putting the blower on it, it's still about the same. Many people with similar mods, boost levels, etc, are in the lower 600s or even in the high 500s in the weaker cases. So, my car seems to conform to what I've read to be true.

 

[Rickyll7]

It shuts off the fuel injectors, not spark.

 

[oxfordgt]

Why would that be an issue? Doesn't the rev limiter just cut spark? If so, then he wouldn't run lean, so no danger.
It cuts fuel which will blow the engine, only after market ignitions cut spark



I hear this song and dance very frequently, and I don't buy it at all. Now, the overlap bleeding off boost makes sense, but I have two responses to that. First, both Tripoli and I have "N/A cams" (more accurately described as having a lot of overlap) and both of us made more boost than we intended and more than people told us we would make. Perhaps we're the oddballs, but this argument doesn't seem to hold water despite the fact that it makes good sense. Second, regardless of whether Tripoli's high overlap cams are bleeding off some boost, he's clearly making plenty at 9psi even with the belt slipping some.

I've read a very well-documented article where a company took two or three pairs of motors (all 4.6 mod motors to my recollection) and measured their power N/A and boosted. In every single case the motor that made more power N/A made more power boosted as well. I'm pretty sure that in all the tests, the only major difference between the motors was the cam profiles. The end conclusion, which seemed to be very solid, was that regardless of what crackpot theories you might come across, the motor that makes more power N/A will make more power under boost.

My car isn't a freak by any means, but it made a pretty healthy amount of power for what was done to it when it was N/A. Relative to other LS1s with similar mods, it was fairly significantly above average, but definitely not the best. I attribute this mostly to the cam choice. Anyway, after putting the blower on it, it's still about the same. Many people with similar mods, boost levels, etc, are in the lower 600s or even in the high 500s in the weaker cases. So, my car seems to conform to what I've read to be true.

I guess you didn't read where I posted that my buddy with just about the exact same setup, except my buddy had blower cams, made 60hp more with only 2lbs of boost more then him and he ran out of pump and had to stop the pull at 5600. I know you don't think that 2lbs of boost by themselves made 60 more hp at that low of a hp level. At most 2lbs of boost is good for 30hp at that level. When you get up into the 1500+hp range then 2lbs makes a much bigger difference.

 

[Gauger]

It shuts off the fuel injectors, not spark.

Good to know. Doesn't seem like the best design.

I guess you didn't read where I posted that my buddy with just about the exact same setup, except my buddy had blower cams, made 60hp more with only 2lbs of boost more then him and he ran out of pump and had to stop the pull at 5600.

No, I did read that, and I figured that would be your response. But, I also have enough experience to know that no two cars are "about the exact same" no matter how hard you try. The comparison you are making while logical still isn't as scientific as measuring two motors before and after adding boost.

Also, I forgot to mention that they discussed how much power the motors put out in terms of percentages (i.e. motor A puts out 120% of what motor B puts out), and they found that the percent difference between engines came very close to remaining the same before and after boost. It is a very convincing argument.

Again, your assertion makes total sense. However, the real world results I've seen myself and read about more often than not show that high overlap cams that produce good power on a NA setup also make great numbers with a supercharger.

 

[oxfordgt]

Well from the many motors I have built or helped build choosing the correct cam for the application always makes more power. Make no other changes to your car other then a blower cam and I guarantee you will make more power. You don't even have to tune for it if you don't want. I would bet my next paycheck on it.

 

[Gauger]

You don't even have to tune for it if you don't want.

This destroyed your credibility.

 

[stagnet04]

Thats crazy....

 

[oxfordgt]

This destroyed your credibility.

How the only reason you need a tune when you get cams is to fix idle issues and to make the most power you can. All I'm saying is he could direct swap blower cams for na cams with no other changes and gain HP. I could care less if the car idles or not.

 

[Tripoli]

How the only reason you need a tune when you get cams is to fix idle issues and to make the most power you can. All I'm saying is he could direct swap blower cams for na cams with no other changes and gain HP. I could care less if the car idles or not.

Changing cams changes the amount of air that enters the cylinder, and therefore changes the A/F mixture. You absolutely would need to update your tune, especially in a supercharged application like mine.

 

[Gauger]

How the only reason you need a tune when you get cams is to fix idle issues and to make the most power you can. All I'm saying is he could direct swap blower cams for na cams with no other changes and gain HP. I could care less if the car idles or not.

I guess that was an extra nail in your already-sealed-tight coffin. I mean, seriously? You only tune for idle issues and to gain HP? That's ridiculous. If you sneeze too hard around a FI car, you should retune and make sure it's not running lean so it doesn't BLOW UP THE MOTOR!!! Forget gaining power and freaking idle issues.

 

[deftsound]

I guess that was an extra nail in your already-sealed-tight coffin. I mean, seriously? You only tune for idle issues and to gain HP? That's ridiculous. If you sneeze too hard around a FI car, you should retune and make sure it's not running lean so it doesn't BLOW UP THE MOTOR!!! Forget gaining power and freaking idle issues.

You may be right but bashing long-standing forum members when you only have 6 posts negates your own credability...not to mention you have a ws6 and your giving advice on a mustang forum...

 

[Tripoli]

You may be right but bashing long-standing forum members when you only have 6 posts negates your own credability...not to mention you have a ws6 and your giving advice on a mustang forum...

We're just trying to make sure people get good advice, and not retuning when you're dealing with a FI car is just a bad idea. He may only have 6 posts here, but he's got more than 1,200 on ls1tech. As for him having a WS6, what does that matter? It's a fuel-injected V8. They all work on the same basic principles, and keeping the air/fuel ratio in the proper range is the single most important thing you need to do to keep them healthy.

 

[Gauger]

You may be right but bashing long-standing forum members when you only have 6 posts negates your own credability...not to mention you have a ws6 and your giving advice on a mustang forum...

Let me address the points individually here...

1) Bashing of long-standing forum members - No bashing took place. We engaged in a debate, and I pointed out the weakness of his argument. There wasn't a single personal insult to oxfordgt in my posts.

2) My post count - This is just a weak statement. Of course my post count is low as I spend my time over on LS1-related forums. Anyone with any experience knows that post counts and horsepower don't mean anything. If I had 60,000 posts instead of 6, that doesn't mean I'm not an idiot. And if I have 6 posts, that doesn't mean that I didn't pick up knowledge outside of this forum. Believe it or not, StangNet is not the only source of car-related knowledge available.

3) My owning a GM car and posting on a Ford forum - Again, a lot of my argument from point #2 applies here. My owning a GM car doesn't mean I'm without knowledge of Fords. I've done quite a bit of work on Tripoli's car, as I'm sure he'll confirm. More importantly, though, the topic of conversation here is in no way brand- or model-specific. Anyone with any car who changes their cam(s) while boosted should get their tune (or carb) checked. The dangers of running lean are worth being careful, and cams are very likely to change things up in that regard.

 

[Rickyll7]

Changing cams changes the amount of air that enters the cylinder, and therefore changes the A/F mixture. You absolutely would need to update your tune, especially in a supercharged application like mine.

Untrue. Adding air to the cylinder does not always mean you will run leaner. If the air passes through the MAF sensor first, as it should, the MAF sensor will read the added air and add more fuel accordingly.

However, I agree that you should get a tune with new cams if you are FI and running a non stock MAF, unless you are sure you aren't going to max your fuel pump, maf sensor, and have a very conservative tune. A non stock maf needs to be calibrated properly (done when tuning) and can only be calibrated up to the max amount of air the engine can consume at that time. The curve given to the maf after that amount of air can be off by 10% or more, so a re-tune is recommended if you have a non stock maf and/or an aggressive tune where 10% less fuel could cause knock.

If you are not FI, and are running a stock maf, then Oxford is right, a tune will only be useful for getting more hp (more timing and less fuel) and to work out possible idle and other driveability issues. A stock maf is calibrated from the factory and will adjust for the added air properly until saturated.

 

[Gauger]

Perhaps the Ford PCM works differently than mine, but even putting headers on is known to make an LS1 run lean. How much worse would a cam be? Answer: A lot.

Still... the bottom line is that the suggestion of changing cams on a supercharged engine that's already on the edge of what the internals will handle and then skipping a re-tune is nothing short of ludicrous.

 

[Rickyll7]

Perhaps the Ford PCM works differently than mine, but even putting headers on is known to make an LS1 run lean. How much worse would a cam be? Anser: A lot.

The GM cars use a volumetric efficiency method for calculating airflow rate. Fords use a mass airflow sensor to measure it. So it is different. I'm not too familiar with the volumetric efficiency method that those cars use, so I'll take your word for it regarding those cars and how mods affect their afr.

Still... the bottom line is that the suggestion of changing cams on a supercharged engine that's already on the edge of what the internals will handle and then skipping a re-tune is nothing short of ludicrous.

Agreed.

However, at the end of the day... Detonation will kill a motor weather it is below or above it's hp/tq limit.

Also, an engine that is operating above it's hp/tq limit is operating on borrowed time, detonation or not.

 

[deftsound]

Let me address the points individually here...

1) Bashing of long-standing forum members - No bashing took place. We engaged in a debate, and I pointed out the weakness of his argument. There wasn't a single personal insult to oxfordgt in my posts.

2) My post count - This is just a weak statement. Of course my post count is low as I spend my time over on LS1-related forums. Anyone with any experience knows that post counts and horsepower don't mean anything. If I had 60,000 posts instead of 6, that doesn't mean I'm not an idiot. And if I have 6 posts, that doesn't mean that I didn't pick up knowledge outside of this forum. Believe it or not, StangNet is not the only source of car-related knowledge available.

3) My owning a GM car and posting on a Ford forum - Again, a lot of my argument from point #2 applies here. My owning a GM car doesn't mean I'm without knowledge of Fords. I've done quite a bit of work on Tripoli's car, as I'm sure he'll confirm. More importantly, though, the topic of conversation here is in no way brand- or model-specific. Anyone with any car who changes their cam(s) while boosted should get their tune (or carb) checked. The dangers of running lean are worth being careful, and cams are very likely to change things up in that regard.

Im not dissagreeing with you about your advice, infact i agree, a tune is essential. But IMO oxford has a lot of credablity and when someone who has 6 posts comes on to the forum negating someone elses credability it tends to make me a little defensive especially when they have a ws6 not a mustang and its on a mustang forum...sorry if i came off wrong

again i agree with what you are saying, a tune is mandatory...

 

[oxfordgt]

The ford PCM delivers fuel according to MAF counts so you will not run lean by change the cam and not retuning. These are not speed density systems. My whole point was that a blower cam will make more power then a NA cam hands down. More air/fuel mixture in the cylinder means more power bottom line. When air/fuel is rushing out of the exhaust because of the extended overlap of the cam you will make less power.

I may have a low post count on this forum but I do know what I am doing and my numbers in my sig should tell you that.

 

[Gauger]

...I do know what I am doing and my numbers in my sig should tell you that.

Power numbers in signatures are meaningless. Go talk to your average customer at a speed shop that primarily works on 'vettes. The vast majority of them have more money than sense (and more power than you or me).

 

[oxfordgt]

But I have pictures to prove that no shop ever touched my car other then to tune it.