Update on 348 Plenum Project

Can you graph the baseline vs post-mod air/fuel ratio per RPM graphs similarly to the above?

 

Yes.... ....................run004 is before mod............... and................. run008 is 'after' mod........
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Thanks.

#1, you're running WAY WAY WAY too lean (tune your MAFS!).

#2, you are running richer after the mods, i.e. less air. But, it's not the mods; it's your humidity difference (because the curve at low and mid RPMs is identical, but shifted)

#3, your top end RPMs are showing a better A/F rate, so your mods are headed in the right direction




(with the same dyno humidity conditions, you may see another +11 hp...and you can certainly get that many more hp again just by tuning your MAFs richer)

 

..looks like we need to get right on this..... ..............hear that Vince?????

 

I'm so disappointed that this did not work. It was the simple idea that had so much promise. At least by your graphs it does not look like it worked to me. I really thought I would be buying lunch but I think you guys owe me lunch! You better take a loan from those 401k's.

The HP gain was only 4hp? That's 1.45% and within the error of the dynojet=no percieved gains.

The A/F ratio is funky. The blue is with the new stuff but if you are flowing more air you should lean out the mixture I.E. higher stoich raito but you are inversed for most of the rpm range. This may be because there is turbulance that is not accounted for dispite being a bigger hole with more volume. The high rpm area looks like stock where the flows should be max so I would expect lean but at least you have not lost anything here.

That's how it looks to me anyway. Is there a version 2? Bigger TB, Bigger plenum spacers, bigger maf or no MAF just oe ecu alfa-N? Is that doable NoDoubt? I bet that MAF is a huge restriction and getting rid of that may make more gains than what you are getting now.

 

Goth,

Why did you use such a small spacer? Did you calculate all this or was it seat of pants?

 

Were the screens removed from the MAFs?

 

Carl............ read the repeatability. This actual dyno is used by many magazine shootouts because it is very accurate. Do you have 'data' to support your stated 'margin of error'? I hope you were joking. These numbers are very honest and accurate. They were not posted for bragging but as an objective point of reference.

Considering the actual material changes to the intake, the gains shown are to be expected. I never claimed any big numbers, only that they would be positive. Regardless of what anyone thinks, no one is going to gain 50hp with just an intake 'smoothing'.

I know there are lots of crazy claims made by others out there..... none of which have produced a controlled honest dyno sheet as this. Remember the exhaust is totaly stock. I have mentioned before that if these gains are not great, it is because the exhaust needs to be un-choked. That is next on the itinerary BTW .

Doing the intake first and as the only mod is the toughest way to show any gains. If I wanted to produce sensational dyno sheets, we would have done the exhaust first for much larger and easier gains...

no.... everything except the smoothing, spacers and TBs was left 'untouched'.

 

No I'm not kidding. I don't know enough about dynos but there are lists of things that can change small results. We would not have an issue with a 100hp gain. But 4 HP? Just being on the dyno rollers cocked could make or break 4 HP.
No trying to bust your chops but what happens if you dump an SAE air correction factor in there does the 1.45% go away? If you got a 3 degree cooler day and strapped the car down tighter on some dynos you increase drag. That could be 1.45% right there. I think SAE CF's take at least the atmospheric conditions into account. Maybe there are real gains maybe not. I think that this small a number could be within the standard deviation of number you would randomly get. I could be wrong you may be right. I am glad you are posting graphs...no one else ever has.

 

It was good seeing everyone again.

When I got there we talked for a few minutes, and then the wrenches started turning. Yup Vince is a Stooge now. I put the boy to work. It was funny because at first he was just watching Plugz and myself disassembling things. He thought he was gonna hang with the Stooges and not turn a wrench, NOT!

EVERYone was working on this thing. It was a big time team effort. Once it was out, we then it took it apart and all the new goodies got put on. After we had all the new stuff on and the intake back in Vince jumped in the car and fired it right up on the first try.

Ozzy really did some nice work on this thing. The inside of the runners looked so nice and clean, and the spacers cam out great. It really looked sharp once it was together and back in.

All in all it was a pretty good day.

 

Too bad chubba. A again is a gain.

Now where do I wanna eat breakfast? IHOP, Denny's, Mimi's, Joe's? Yup that 4hp sure is gonna taste real good going down. Mmmmm, mmmm, mmmm.

 

I guess another trip to the dyno when the humidity goes down will be interesting. The humidity was high because it rained the next day. Plus Vince never reinitialized the ecu's by disconnecting the battery. I think he should disconnect the battery, let it go through the relearn procedure, wait for the weather to get better, and the do another pull on the dyno. Plus while it's on the dyno he can tweek the MAFS to see if it helps get any more ponies.

 

Been watching this thread anxiously! Thanks for the follow-through and actually posting dyno numbers; good data is one of the best things we can have with any mod.

I'm admittedly not a tuning expert, but ND's obersvations on mixture underscore the point that you haven't really tuned the car yet and I suspect there are more substantial gains to be made when you get the entire system matched: intake, exhaust, ECU, cats.

Also, HP may not the only metric you may improve. Your mods may end up providing comparable HP gains to other mod packages, but also offer more low end torque or significantly improved throttle response.

Keep up the good work! You're fans are cheering you on from the sidelines.

 

All very true, but Vince did the right thing to isolate the dyno runs regarding changes to air intake flow.

But yeah, now that the airflow is known, you can tweak out some more ponies (e.g. remove MAF airscreens, decrease MAF resistance to 355 ohms, reset the Motronics, and test on a lower humidity day).

 

Originally Posted by No Doubt
(with the same dyno humidity conditions, you may see another +11 hp...and you can certainly get that many more hp again just by tuning your MAFs richer)

Not sure how you get 11hp but thats what the SAE air correction factors do take the guess out. Also the humidity is a smaller term in the correction factor but the air temp is a huge term in the equation. I'm not a math guy nor do I know all the ins and out of dyno work but I do know there are things to question expecially when the results are close. And if you guys take a stock car and do a custom ecu tune Vette guys and similar cars are seeing 5% HP gains just from that and on the order of near 20% with CARB legal cat back exhaust and intake mods. More HP if you go illegal with headers/street perfomance cam. Those custom ecu tunes make up for the small variations in each individual engine for wear etc... So for all these changes 1.45%? I bet you could tune the old stock motor for more than 1.45%. I'm not trying to put the project down I'm just wondering how we can get definative HP/torque where no one will question it was a better modification.

 

FBB, my friend, I'm very disappointed in you. Doubting the benefit of improved airflow jeopardizes your credibility as Fchat's leading skeptic and in fact qualifies you for membership in the Flat Earth Society!

 

If you give the dyno guys a call they can tell you if it's a corrected or raw number and can probaly email the SAE corrected version if that is not what they gave you.

Also it will make peak hp with an AF of around 13.2 normally so I'd guess there is about 10hp left on the table right now with that lean mixture.

 

It was an improvement all across the power band. Yes it was small, but it was still an improvement, which to me proves that gains can be made by increasing the air going to the engine. These were solids gains backed up by posted dyno numbers.

Look at the gains Andy made with his individual throttle bodies. Then there are the gains Plugzit made with his ITB set up off of a 355, and he hasn't even really tuned his car to take advantage of the increased air flow. Then we have the sweet custom plenum that Group77 made for his car. Those netted him some nice gains, plus he also freed up the exhaust.

Over all to me this proves that our 348's do indeed have untapped power. With these mild mods that were done on Vince's car it just reenforces it more. He gained 4hp & 2lb/ft of torque, and all that was pretty much done was to smooth out the intake runners, open up the throttle bodies just a little bit, and some spacers. Nothing really radical. I really feel that the 348 engine is just plugged up. All that we need to do is unplug it on both the intake and exhaust ends and we will see some pretty good improvements in power.

Now what do I wanna eat for breakfast?

 

That generally points to measurement error or ambient condition changes. It very very unusual for any change to any part of the engine to shift the entire curve by about the same % from idle to redline, it possible, but unusual.

I for one would LOVE to look at the gains from those changes, can you point to the before after dyno sheets?

Not to be negative, I love these projects, all very cool...... but the improvements don't seem to be very well documented.

 

You mean the butt dyno doesn't count???? LOL!

No the other guys didn't post before or after dyno sheets. But the before and after dyno numbers for this minor mod were posted and they showed a small gain.

Smoked bacon and eggs sounds good. Hahahahaa!

 

YES! I think that bears a repost. Mike by the way has huge experience with these things. I am a good part replacer but Mike understand in depth how mods can change engine function.

 

This is getting ridiculous.......

1. The reason we did not do any MAF or ECU tuning was to isolate the result as being from the intake mods only and not tainted by any tuning.

2. As I have stated before (see post 49 note 2.). I should have opened up the 'hour glass' instead of essentially smoothing it out. The reason I held back was I did not want to lose bottom end power. But since Vinces runners are now in my possesion I will do just that.

3. Who ever does not want to believe the intake produced any gains, is free to believe what ever they want. But when one starts stating the modest gain was within "measurement error".......... please produce some real first hand data to substantiate those statements. Not just my mechanic did this and my tuner did that. The repeated baseline dyno runs essentially overlayed each other. The mod runs overlayed as well. This particular Dyno is very consistent. The car will not run on the dyno crooked as some may believe. The car will straighten itself, we then readjust the tiedowns.

4. As I have stated many times before these runs were done to chart the difference of the very minor intake manifold changes ONLY.

5. For general comparison and reference. I ran my F355 on the same dyno with capristo exhaust then with stock exhaust, with that being the only change. The difference was 8.25HP better with the capristo..... believe what you want.

6. Vinces 348ts exhaust is next... I am predicting at least 15 real HP when that is done. Not 20% or other exagerated numbers that are freely being tossed around here. Final ECU tuning will done to compensate these changes.

7. It does not matter what chart is posted, there are some here that will come up with some reason not to believe and try to convince others while they are at it. Even if an SAE chart showed even one real HP better, the same person with no data and no knowledge of the extent we went through to make this a truly honest test, will say it isn't or can't be so.

8. Maybe next time instead of posting the truth we will post a 20% gain, since for some that is apparently more believable.....

 

I don't in any way mean to say that what you guys did didn't make 4 more hp or that doing things 1 step at a time isn't the right way to go, it is. I only wanted to point out that you should confirm if the runs are raw or corrected becasue it matters and since the runs weren't done on the same day you need to use corrected data. I also wanted to point out that when you get to the next step and re-map to match your ported intake you will gain more. It might be worht remapping to see exactly what the full gain is from your intake mods before going on to the exhaust....but it you just skip to the exhasut and then remap you save dyno time and having to do it twice.

It's a great project!

 

As someone who is in the learning phase and contemplating a project of my own, I appreciate the fact you guys have been so willing to share every detail of your project. This is real world stuff that can't be gleaned from how-to books and manuals. The data points alone from the incremental vs. cumulative effects of each stage will be valuable to all 348 hot-rodders.

 

+1