Plenum results on the way!

68 & 00 GT · Jan 19, 2004

If my theory is correct I know what i'd do, but To see the same test w/ 75mm TB's would close this case for us all forever !

Ask Accufab why not add a 75mm TB with their plenum.

03trubluGT · Jan 19, 2004

68 & 00 GT said:
good job Matt.
I believe the Accufab gives the most power by this test. Add a 75mm TB to all three and do the same test, and it only makes sense that the Accufab still makes more power w/ a 75 mm than the others w/ a 75mm TB.

Matt wasn't your previous test like this on the ported plenum ?

BTW - who is doing your dyno's ? Is it in Lewisville ?

The dyno is at Speedworks in Lewisville.

I've been happy with them, they are great to work with and it costs $45 for 3 pulls.

www.txspeedworks.com

And yes, I did this same thing with the ported plenum and gained 3hp/3tq.

Matt

03trubluGT · Jan 19, 2004

Highroller said:
Matt-

Not trying to knock the test.. I'm ready to buy and I'm trying to figure out which to go with... also you guys are mentioning that buy adding a 75mm throttle body to these tests would increase the power.. but again Accufab has stated that their 70mm Throttle body should be used with their Plenum. I would think if their 75mm made more power, why wouldn't they recommend that one

Either way, I have a 75mm Throttle body, and I have to pick which Plenum to order.. It's between the Dragon or the Accufab (Now seeing this comparision) I'm just worried I'm going to pick the wrong one!!

No offense taken. I just worked with what I had.
I would have like to do a bigger test, but I'm just an individual.

I can't see that big of a plenum helping. The 70mm is alot bigger than the 75, but like I said, I'm no airflow expert.

You can wait till someone else tests before you make your purchase, or you can buy it a duplicate my test! It's your money...

Matt

JonJon · Jan 19, 2004

Doesn't Accufab make a 70mm AND a 75mm intake plenum? Or did I misread that somewhere?

Highroller · Jan 19, 2004

JonJon said:
Doesn't Accufab make a 70mm AND a 75mm intake plenum? Or did I misread that somewhere?

Well, I will like to say that I can do a before and After test like you did.. with my stock plenum and 65mm. but in all honesty I won't (I ordered the dragon and will combine that with my 75 Throttle body and call it a day)

It takes alot of dedication, time and understanding (from the wifey) to do a dyno shootout like you did..

I know your results helped me.. and I know that I will feel a good gain.. how much, I will never know!! until someone else does that dyno run

KenB · Jan 19, 2004

Highroller said:
Well, I will like to say that I can do a before and After test like you did.. with my stock plenum and 65mm. but in all honesty I won't (I ordered the dragon and will combine that with my 75 Throttle body and call it a day)

It takes alot of dedication, time and understanding (from the wifey) to do a dyno shootout like you did..

I know your results helped me.. and I know that I will feel a good gain.. how much, I will never know!! until someone else does that dyno run

You guys are really confusing the topic. Don't be overly concerned with peak numbers, pay attention to the area under the curve. It's quite possible that the Accufab would pick up peak power with a 75, but with a 70mm it has better power throughout the power band which is more important.

Unfortunately, too many people are stuck at looking at peak numbers. Accufab is run by a racer, the fastest mod motor car ever, keep that in mind. I applaud Accufab for recommending a TB that provides best overall power and not be too concerned with peak.

Ken

wms004 · Jan 19, 2004

Highroller said:
the question that I have is as follows:

if the Accufab team recommends only a 70mm Throttle body.. and its proven that a 75 mm throttle body works better on the C&L and Dragon.. then wouldn't we be making more power for going with the Dragon and a 75 MM Throttle body.. (I picked Dragon because they were #2 on the comparision)

What I mean is we saw Accufab's peak power.. but with the Dragon and C&L it's proven that we can get another 3-4 HP out of the combo by upgrading to a 75mm Throttle body??

unless Accufab's plenum gets more HP with a 75mm Throttle body?

It would be unusual that Accufab would suggest a 70mm if it made less power than with the 75mm.. Based on results I have seen, it would be very plausible for the Dragon and C&L to make more power (that lost 3-4tq + added hp) with a 75mm since they respond better to it. Once i ever get money I'll get that accufab 75mm t/b!

-wade

2000GT · Jan 23, 2004

Matt - any chance you could post the before and after a/f ratios from each plenum/TB combo?

There are some of us (mostly me) that are really curious to see the those combos change the a/f ratios, if so, leaner or richer. I am trying to avoid getting another tune if I add a plenum/TB combo.

My guess is that they lean the car out a bit more, hopefully nothing major.

NasaGT · Jan 23, 2004

Matt - thanks for your time, energy, and $$ in this project. A great help to the rest of us!

KenB · Jan 24, 2004

There were no changes to the A/F as there shouldn't be. With either a stock tune or a tune done correctly, the EEC commands a A/F ratio and will add the correct amount of fuel accordingly.

Things like a C&L MAF trick the EEC and will cause havoc with the A/F ratio.

Ken

2000GT · Jan 24, 2004

Interesting and different from with what Lee Bender told me at C&L regarding his product. He told me the biggest change they have seen to the a/f ratios on their test cars was (0.3:1). I'd just like to understand why.

Either way, we are not talking about any major a/f changes and that's good to know.

Thanks.

03trubluGT · Jan 24, 2004

2000GT said:
Interesting and different from with what Lee Bender told me at C&L regarding his product. He told me the biggest change they have seen to the a/f ratios on their test cars was (0.3:1). I'd just like to understand why.

Either way, we are not talking about any major a/f changes and that's good to know.

Thanks.

Ken is correct. That's why he didn't post all of the redundant data in the article.

The a/f started out lean (like they all do) and gradually went to about 13:1 where it leveled off. There were no concers, as the a/f on the aftermarket plenums looked like the stock one.

Matt

forpit2000gt · Jan 25, 2004

the A/F will be determined by the MAF and O2 sensors if I an correct. Why would the plenum change anything greatly if all electronis are working correctly?

redlined50 · Jan 26, 2004

if the a/f ratio is way off then the comp will think something is wrong and will go to pre set values (limp home mode)

2000GT · Jan 26, 2004

redlined50 said:
if the a/f ratio is way off then the comp will think something is wrong and will go to pre set values (limp home mode)

Yup, I think that's correct and "limp mode" is a rich a/f ratio because it's "safe". When I added my x-pipe and had my car dynoed, I actually lost hp. and tq. and my a/f ratio went super rich. I then had it dynoed again about a month later and it dynoed higher (I only dyno in SAE form). I think the computer just needed time to process the x pipe changes and reconfigure the optimal a/f ratio for the mod. The problem or limitation is that the Ford stock programing doesn't account for the addition of x pipes, h pipes, larger TB's, MAF's, etc. and can't adjust accordingly. At the end of the day, a dyno tune is needed for optimal a/f ratios and engine timing.

I just hope my current tune can adjust (favorably) for the larger TB/plenum. The key word is "favorably". I hate to add these bolt-on's and have my car go into safe mode because it senses a larger volume of air entering the engine. Hopefully my MAF and oxygen sensors will note the additional volume of air entering the engine and add more fuel to seek my 13:1 tuned a/f ratio.

Plenum results on the way!

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