Naturally Aspirated "GURUS", come in, come in...
#76
04-01-2009, 11:22 AM
Join Date: Nov 2002
Location: St.Pete, FL
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Final drive gear ratio is one of the most important options in a car, even a street car. I have 4.08 gears because the whole premise of my car is high RPM NA power.
The Cosworth plenum was originally designed for high RPM NA VQ engines... I'm hoping that the Cosworth plenum along with a few other intake modifications will help get more air into my engine in the upper RPM range.
There is a big difference in how NA and FI engines get their air. The intake side of an FI engine isn't as critical as it is on an NA car... no boost to turn up.
The Cosworth plenum was originally designed for high RPM NA VQ engines... I'm hoping that the Cosworth plenum along with a few other intake modifications will help get more air into my engine in the upper RPM range.
There is a big difference in how NA and FI engines get their air. The intake side of an FI engine isn't as critical as it is on an NA car... no boost to turn up.
#77
04-01-2009, 12:05 PM
One critical factor regarding FD that I forgot to mention (I always forget about this when the topic comes up) – is that if you are AT running 3.3 FD and want to switch to shorter gears (3.5, 3.7), you will need an MT differential… the 3.3 ring gear is thicker than the others so it will not fit with the AT open diff… any MT aftermarket or OEM will work… When doing FD, it a good time to upgrade to LSD anyway.
This is why many AT just use 3.5FD, because its easy to obtain an OEM pumpkin that has the everything you need…. With the added acceleration form the shorter gears, some kind of LSD is advantageous anyway (particularly when taking spirited tight corners). I have Quaife ATB diff with 3.7
*** someone may have already mentioned this since my last post – but it came to mind this morning and I wanted to post quickly before someone spends too much time planning FD for AT without knowing about the differential.
This is why many AT just use 3.5FD, because its easy to obtain an OEM pumpkin that has the everything you need…. With the added acceleration form the shorter gears, some kind of LSD is advantageous anyway (particularly when taking spirited tight corners). I have Quaife ATB diff with 3.7
*** someone may have already mentioned this since my last post – but it came to mind this morning and I wanted to post quickly before someone spends too much time planning FD for AT without knowing about the differential.
#78
04-01-2009, 12:42 PM
Join Date: Apr 2007
Location: Bay Area..Miami
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#80
04-01-2009, 01:30 PM
I do know for fact that its very hard to make it through ¼ mile in 3rd gear at 7200 rev limit (there is no way to do it with OEM rev limit)… but once I upgraded a couple internals to (hopefully) safely bump to 7500, its no problem getting to finish line in 3rd.
I can tell you it makes corner exit speeds much snappier!!
#81
04-03-2009, 03:08 AM
Hey Guys!!
I think (pretty sure) I am going to try and sell my Stillen Stg2 SC kit that I never installed and keep the coupe NA.
So, since I haven't been on here in a while asking about NA "bolt on", I thought I would re-ask the question to get some good feedback and maybe start a chat or two about what's new out for our coupes (03'-07' models) for the Naturally Aspirated enthusiasts.
What I have: 2003.5 Coupe
Gordie Grouding Kit (love it!)
STILLEN "True Dual" cat-back exhaust (I kiss it good night, best mod I've ever done for this coupe!!!! - HIGHLY recommend)
What I was thinking of getting if going the NA route afterall:
1.) Motordyne 5/16" spacer w/ iso thermal
2.) Motordyne MREV2 lower plenum collector - can I use this on my non-rev with the 5/16" spacer with POSITIVE or NEGATIVE results!?!?
3.) STILLEN headers
4.) STILLEN High Flow cats
My main worries are the Motordyne combo asked in question #2 and then if that passes for a "good mod to do", then what would HF Cats and Headers do with that combo - good or bad outcome!?
I do NOT want to LOOSE TQ, I want MORE!! he-he
What else could I be missing for NA route? - Oh the ECU reflash! Forged Performance is a bicycle distance from where I work. Let them do the ECU or send it off to TECHNOSQUARE?
All comments welcome - I remember to put on my flame suit for anyone having a bad day.
Thanks Guys!
-WoW
I think (pretty sure) I am going to try and sell my Stillen Stg2 SC kit that I never installed and keep the coupe NA.
So, since I haven't been on here in a while asking about NA "bolt on", I thought I would re-ask the question to get some good feedback and maybe start a chat or two about what's new out for our coupes (03'-07' models) for the Naturally Aspirated enthusiasts.
What I have: 2003.5 Coupe
Gordie Grouding Kit (love it!)
STILLEN "True Dual" cat-back exhaust (I kiss it good night, best mod I've ever done for this coupe!!!! - HIGHLY recommend)
What I was thinking of getting if going the NA route afterall:
1.) Motordyne 5/16" spacer w/ iso thermal
2.) Motordyne MREV2 lower plenum collector - can I use this on my non-rev with the 5/16" spacer with POSITIVE or NEGATIVE results!?!?
3.) STILLEN headers
4.) STILLEN High Flow cats
My main worries are the Motordyne combo asked in question #2 and then if that passes for a "good mod to do", then what would HF Cats and Headers do with that combo - good or bad outcome!?
I do NOT want to LOOSE TQ, I want MORE!! he-he
What else could I be missing for NA route? - Oh the ECU reflash! Forged Performance is a bicycle distance from where I work. Let them do the ECU or send it off to TECHNOSQUARE?
All comments welcome - I remember to put on my flame suit for anyone having a bad day.
Thanks Guys!
-WoW
#82
04-03-2009, 07:41 AM
basically...homeboy op just gotta get all the things down as far as bolt-ons goes and then get a tune.
but if it was me.
stock airbox, with z tube and drop in filter for intake setup.
Tomei headers with tomei test pipes or some sort of resonated test pipes
or forget that noise and money and get the megan longtube headers which eliminated the need to buy test pipes and "best headers" question/situation.
5/16 or 1/2" motordyne plenum spacer and if you want the mrev, it's all you playboy...
Exhaust...2.5inch - 3inch whatever you like. motordyne is good or fast intentions.
Final drive gear, but you'll have to live without cruise control unless you can get that ish tuned to where the ecu would be able to work with the new faster gears.
and then if that isn't enough for your driving needs, go internal style with cams and if you got the money for it, stroker kit and ITB's
and don't forget to upgrade transmission..valvebody upgrade and shift kit, oil cooler and if that isn't enough...you're just sick in the head. lol jk
but if it was me.
stock airbox, with z tube and drop in filter for intake setup.
Tomei headers with tomei test pipes or some sort of resonated test pipes
or forget that noise and money and get the megan longtube headers which eliminated the need to buy test pipes and "best headers" question/situation.
5/16 or 1/2" motordyne plenum spacer and if you want the mrev, it's all you playboy...
Exhaust...2.5inch - 3inch whatever you like. motordyne is good or fast intentions.
Final drive gear, but you'll have to live without cruise control unless you can get that ish tuned to where the ecu would be able to work with the new faster gears.
and then if that isn't enough for your driving needs, go internal style with cams and if you got the money for it, stroker kit and ITB's
and don't forget to upgrade transmission..valvebody upgrade and shift kit, oil cooler and if that isn't enough...you're just sick in the head. lol jk
#83
04-03-2009, 01:22 PM
it starts as a non-rev-up lower collector - but it is machined to become MREV2... I have a similar type lower collector (just more detailed machining)... it does give minor gains on the non rev-up.
#84
04-03-2009, 01:35 PM
basically...homeboy op just gotta get all the things down as far as bolt-ons goes and then get a tune.
but if it was me.
stock airbox, with z tube and drop in filter for intake setup.
Tomei headers with tomei test pipes or some sort of resonated test pipes
or forget that noise and money and get the megan longtube headers which eliminated the need to buy test pipes and "best headers" question/situation.
5/16 or 1/2" motordyne plenum spacer and if you want the mrev, it's all you playboy...
Exhaust...2.5inch - 3inch whatever you like. motordyne is good or fast intentions.
Final drive gear, but you'll have to live without cruise control unless you can get that ish tuned to where the ecu would be able to work with the new faster gears.
and then if that isn't enough for your driving needs, go internal style with cams and if you got the money for it, stroker kit and ITB's
and don't forget to upgrade transmission..valvebody upgrade and shift kit, oil cooler and if that isn't enough...you're just sick in the head. lol jk
but if it was me.
stock airbox, with z tube and drop in filter for intake setup.
Tomei headers with tomei test pipes or some sort of resonated test pipes
or forget that noise and money and get the megan longtube headers which eliminated the need to buy test pipes and "best headers" question/situation.
5/16 or 1/2" motordyne plenum spacer and if you want the mrev, it's all you playboy...
Exhaust...2.5inch - 3inch whatever you like. motordyne is good or fast intentions.
Final drive gear, but you'll have to live without cruise control unless you can get that ish tuned to where the ecu would be able to work with the new faster gears.
and then if that isn't enough for your driving needs, go internal style with cams and if you got the money for it, stroker kit and ITB's
and don't forget to upgrade transmission..valvebody upgrade and shift kit, oil cooler and if that isn't enough...you're just sick in the head. lol jk
Bold green; I would add ATF cooler to that list.
#85
04-03-2009, 01:59 PM
Join Date: Nov 2002
Location: St.Pete, FL
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The ECU has a failsafe that measures the speed of the driveshaft and the speed of the wheels... When the difference is higher than what the ECU expected, it thinks something is wrong and disables cruise control.
When you install a different final drive ratio, you alter the ratio of driveshaft to wheel RPM. As you increase speed, the delta between them gets larger... at some speed point, the ECU will disable the cruise control. I believe it affects automatic cars more than manual transmission cars. I have a 6mt and 4.08 gears and have set the CC at close to 90 mph and it works fine.
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