Hp/tq gains with 3.0 intake cams on a 3.2??

[intimdatr]

Granted it was not a back to back result but someone who put the mtx cams in an ATX ran nearly a 16s 1/4 mile. I feel thats enough proof for most. SHOspazz92 I beleive had a 3.2 MTX with the stock ATX cams still installed and said it was one of the most fantastic "low mod" car he ever daily drove (paraphrasing a bit). But the torque of the ATX cams really make these cars fun. Having a cammed up MTX car, the desire for peak power is 1) expensive and 2) kills the daily fun factor of the car anything below the nearly 5500 rpm where the cams really come alive.

[email protected] - JustinSane '95 (mtx cams)

Im sure it sounds like were trying to attack you, but were trying to prevent you from investing a lump of money and ending up not pleased and upset with the results.

 

[sperold]

Get the cams from the wrecking yard. Get all the shims for each cam lobe and put them in an egg carton with the lobe noted on each one.

Think long and hard before you install them.

Run your car with the automatic cams in place following your transmission rework. Get it running correctly and keep good records.

Swap in your MTX cams later during one of your future operations, and keep good records on it as well.

In the meantime, find someone with a Honda S 2000 or a Mazda with a rotary and ask them about the need for high rpms, for every single thing they do, including getting the groceries.
I once heard it explained that pulling away from a stop sign with the Mazda rotary automatic was like "stepping on a grape". Yet it had high horsepower numbers.

 

[broke1]

I saw that almost 16 second 1/4. Maybe it was an all stock car??

I know Area under the curve is what u want,but if it only kills 4-5 ft lbs on the bottom end power band while gaining 10-15hp/10 tq above 4k then I'd think good mod for $$.

I've thought true dual exhaust but the only 1 I could find liking it was Ted B(orig lpm guy) every1 else says duals sound crappy and lose power.

I wish area91 would reply so we could see what meant by not worth it unless u have other mods..

 

[rubydist]

the Mazda rotary is not difficult to drive because the rotary torque curve is pretty flat - there is not a lot of torque anywhere... but the S2000 is peaky and it needs to run fast, and unless you want to act like a Formula1 racer every time you go out, its not very quick. (the S2000 has 200 hp but way less torque, the rotary turbo was close to 200 hp but again less torque.)

 

[jimtash]

^^ This is the point that you may not be fully comprehending, broke1.

Of course, 3.0 intake cams in a atx car will result in more horsepower. That does NOT mean it will be a faster or quicker car. What you care about is the area under the torque curve in the rpm range that you actually drive the car.

When you put 3.0 cams in a 3.2, you drop the torque curve below roughly 2500-3000 rpm. That drop in torque in that rpm range means that you need more throttle to get the same response for most driving. That translates to a feeling that the car is slower (because it is) and a reduction in gas mileage.

I had a 3.2 mtx that I drove for a while and then put 3.0 intake cams in it. If I got on it (above 3000 rpm), it was faster. For regular driving, it was doggier and gas mileage went down (because my daily driving kept rpms in the 2-4k range 90% of the time).

It depends on what you plan to do with the car. If you want an atx race car, then the cams will help you. If you want a quick daily driver, then save the time.

IMO, the 3.2 with 3.0 cams is fine. I actually enjoy the car much more because of the cruising action down low. Nice torque and plenty of power in the mid range. It's very easy to drive in traffic.

 

[Slo-Sho]

The MTX intake cams are .020" larger over the ATX. Also, here's the biggie...The MTX cams are dialed in 4* ******** over the ATX cams from Ford....and anyone who knows... The cam timing alone will affect the power band immensely. NOW, what I'm unsure about is if the ATX/MTX cam sprockets are different OR if the 3.0/3.2 mark on the timing belt has something to do with it. Things that make you go hmm...

 

[sperold]

If this is going to be a fun track car and not a daily driver, then feel free to try everything that comes to mind. If people on this forum had access to a tranny shop as you are describing, with the prices as good as reported, there would be a lot more automatic SHOs out there.
Try your ideas out, you can always switch back if they don't pan out.
Good luck, and I applaud your enthusiasm.

 

[rubydist]

The MTX intake cams are .020" larger over the ATX. Also, here's the biggie...The MTX cams are dialed in 4* ******** over the ATX cams from Ford....and anyone who knows... The cam timing alone will affect the power band immensely. NOW, what I'm unsure about is if the ATX/MTX cam sprockets are different OR if the 3.0/3.2 mark on the timing belt has something to do with it. Things that make you go hmm...

the mark on the belt has nothing to do with that.

the 3.2 has an idler on the "tight" side of the timing belt (between the crank and the front cam sprockets) and that makes the belt length 1 tooth longer on the atx cars. that is all.

I had never looked at valve timing on 3.0 v. 3.2 cams, but if the 3.2 is advanced 4* from the 3.0, that alone is a significant part of the lower end torque increase and the fact that it runs out of steam sooner on the high end.

and, no you cannot just adjust the cam timing one tooth on the belt. iirc, the cam sprockets are 24 teeth, which means that one tooth changes timing 15* which is WAY too much!

 

[Slo-Sho]

I say go for it, use the 3.0 intake cams only, with the ATX cam sprockets so you'll have the .020" lift with the 4* adv ATX cam timing. Valve lash set to the lower end of spec. And on another note, these AX4S trannies run hot! Get yourself a trans temp gauge and the biggest stacked plate cooler you can fit, the 30,000 GVWR one comes to mind. You will also need to reinforce the smooshy weak front motor mount to deal with the drag type launches, it will break on you(watching your motor slam your hood up makes you feel really not good). Don't forget to gasket match the intake ports on the head when you do your intake or there will be a ledge there. The 3.0 intake I suppose could be installed on your ATX but...the crossover tube with DIS is different, the EGR valve mount, the DPFE (egr sens) mount, the IAC is different and maybe something else... Just things to think about. I hope you break into the 12's man!

 

[rubydist]

^^ several pieces of mis-information in the above post...

the cam sprockets are identical between 3.0 and 3.2, so if you put in 3.0 intake cams you get 3.0 valve timing. (someone has made adjustable cam sprockets, to allow timing changes, but they are rare and expensive)

the 3.0 intake does not fit on an atx car, that is why they designed a new crossover tube. (the engine is located farther forward) and the atx car will throw codes and cel if you remove the egr (unless you turn it off in the tune) and all the atx rear exhaust manifolds have the egr plumbing.


I had a atx with solid front mount once - had a distinct "kick" at startup, but otherwise did not increase nvh noticeably.

 

[Slo-Sho]

^^ several pieces of mis-information in the above post...

the cam sprockets are identical between 3.0 and 3.2, so if you put in 3.0 intake cams you get 3.0 valve timing. (someone has made adjustable cam sprockets, to allow timing changes, but they are rare and expensive)

the 3.0 intake does not fit on an atx car, that is why they designed a new crossover tube. (the engine is located farther forward) and the atx car will throw codes and cel if you remove the egr (unless you turn it off in the tune) and all the atx rear exhaust manifolds have the egr plumbing.


I had a atx with solid front mount once - had a distinct "kick" at startup, but otherwise did not increase nvh noticeably.

Since he's putting the 3.0 cams into an ATX car it will have 3.2 cam timing. I didn't say definitively the 3.0 intake could be used on the ATX which is why I pointed those differences out....

 

[Slo-Sho]

As per SHO NUT

"As a primer, here are the measured specs of the stock cams:

MTX Intake 0.348” Lift, 205° Duration @ 0.050”

MTX Exhaust 0.328” Lift, 201° Duration @ 0.050”


ATX Intake 0.328” Lift, 201° Duration @ 0.050”

ATX Exhaust 0.328” Lift, 201° Duration @ 0.050”



The ATX Intake chain ****** is also advanced 4 crankshaft degrees relative to the MTX cam. As the Intake chain ****** is what drives the Exhaust cam, this effectively advances the Exhaust cam in an engine with ATX cams by 4 crankshaft degrees, which also reduces the overlap by 4 crankshaft degrees. Compounded with less duration on the ATX intake lobe, there is substantially less overlap with the stock ATX cams. In total, there is 6 crankshaft degrees less overlap, 4° due to the advanced exhaust cam, and 2° due to 4° less intake duration (1/2 of the total duration difference). Note that if you are regrinding cams, it is critical that both intake cams be either MTX or ATX, or you will have mis-matched exhaust lobe centerlines between banks due to the 4° difference between MTX and ATX exhaust cam timing, as driven by the intake cam flanges."

This explains why a stock 3.2 ATX responds very well to turbo charging, less overlap and why the 3.0 just screams on the big end of the tach, more overlap.

 

[jimtash]

Since he's putting the 3.0 cams into an ATX car it will have 3.2 cam timing. I didn't say definitively the 3.0 intake could be used on the ATX which is why I pointed those differences out....

 

[Slo-Sho]

The camshaft timing is different on the ATX/MTX cars due to the intake chain flanges. The intake lobes are also different, I know it gets a bit confusing.

 

[Slo-Sho]

Hey JimTash if you're still dazed and confused post another funny pic!

 

[broke1]

I planned on using the MTX intake I have and porting it. An having the egr disabled in the tune. Can I just use my ATX crossover/sensors?? MTX intake not working on my car screws me up...

 

[jimtash]

The camshaft timing is different on the ATX/MTX cars due to the intake chain flanges. The intake lobes are also different, I know it gets a bit confusing.

 

[jimtash]

I planned on using the MTX intake I have and porting it. An having the egr disabled in the tune. Can I just use my ATX crossover/sensors?? MTX intake not working on my car screws me up...

Should. Only sensor on the ATX intake is the DPFE which controls the EGR.

 

[Slo-Sho]

He looks more dissapointed than confused...

 

[Slo-Sho]

I planned on using the MTX intake I have and porting it. An having the egr disabled in the tune. Can I just use my ATX crossover/sensors?? MTX intake not working on my car screws me up...

Yeah it'll work if you're going that route.