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l67 Motor modding advise needed

tms8582

tms8582

New member
I've got the stock motor pulled on our 02 GTP (good running motor with 100K) Installing SLP headers, 1.9 rockers, springs, timing chain and a smaller pulley of course.... (exact size will be determined when tuned)

I was considering a ZZP intercooler along with porting the m90 and intake.... However it's getting really expensive and I'm thinking about just porting the intake and blower instead.

The question I have is how much benefit would the ported intake and blower offer without adding the intercooler?
 


Just the porting will pretty much add nothing. It does help to open up the V on the outlet of the blower, but the intake does not need to be touched unless you are going to intercool.
 
Gas mileage could be the only argument there... but really if you want power, get a cam, its worth losing a couple MPG, and will give the motor a ton more room to grow in the future!
 


If he sticks with something lets say like the VS cam his gas mileage won't suffer. Especially if he gets a tune specific for it.
 
You shouldnt lose any MPGs with any cam really.

Nick ran his thrasher cam with some stupid rich tune and still got 28-30 on the freeway. If all about how to set up the tune and your driving style.
 
Yeah I was thinking about the cam but already have the rockers... I've heard the 1.9 rockers allow a decent amount of more air flow without losing mileage. So porting the m90 doesn't do much? Maybe I'll go the Gen 5 route instead? Whadda guys think?
 
Its a butt load cheaper to just run a smaller pulley than spending 200-300 pointless dollars on a blower. Who cares if it is more efficent, its really a pointless mod for about 95% of us.
 


Fivefingerdeathpunch said:
Its a butt load cheaper to just run a smaller pulley than spending 200-300 pointless dollars on a blower. Who cares if it is more efficent, its really a pointless mod for about 95% of us.
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This is a good point. Somewhere on the regal forums I read a thread about a very in depth comparison of the Gen V and Gen III blowers. There were really tiny differences, plus it is not just the blower you have to buy, you would also need an entire N* setup, or at minimum an adapter plate to run your L67 TB. Also, I could see cruising freeway MPG not being affected, but I would assume like most people you do a mixed driving, and with more power, how do you not get into it a little here and there!
 
This is a good point. Somewhere on the regal forums I read a thread about a very in depth comparison of the Gen V and Gen III blowers. There were really tiny differences
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That guy is a troll that spends hours a day trying to spread around bad information for seemingly no reason.

Id say it is pretty well accepted that you will lose 2-4mpg with a VS cam and even more with an XP..
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How many have you tuned? Timing? afr at cruise? Cam install angle? I have always gained ~2 mpg with a xp over a well tuned stock car.. going from factory stock to XP we have pulled almost 10mpg better highway out of some cars.

So porting the m90 doesn't do much
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You can port a gen3 to almost where a gen5 is at in terms of gains. There is a bunch of stuff you can fix on the gen3's inlet and outlet to really get it close.. although after the 5 hours you have into porting it you are probably just better off getting a gen5 if you find a cheap one... its pretty easy to see 5% gains from either porting or a gen5 swap.

I've heard the 1.9 rockers allow a decent amount of more air flow without losing mileage
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While they are a decent mod.. its really just designed to be a lazy bolt on deal. modded stock rockers make good 15whp gains across the board, but for the cost they are not quite worth it compared to a cam. Roller style 1.9 rockers are basically worthless, and its hard to even see gains out of them. You can easily sell rockers on here for good money which you can trade for a cam.. I have done this in the past for customers before without much hassle.
 
Thanks for the info darkhorizon. Your right about the 1.9 being an easy bolt on because originally I was planning on installing the headers from underneath and just bolting in the stock modified 1.9's. Then I decided to pull the motor, clean and paint everything in the engine bay. I guess now would be the time to go with the XP cam now that I think about it... Sounds like you work in the industry?
 
darkhorizon said:
That guy is a troll that spends hours a day trying to spread around bad information for seemingly no reason.



How many have you tuned? Timing? afr at cruise? Cam install angle? I have always gained ~2 mpg with a xp over a well tuned stock car.. going from factory stock to XP we have pulled almost 10mpg better highway out of some cars.



You can port a gen3 to almost where a gen5 is at in terms of gains. There is a bunch of stuff you can fix on the gen3's inlet and outlet to really get it close.. although after the 5 hours you have into porting it you are probably just better off getting a gen5 if you find a cheap one... its pretty easy to see 5% gains from either porting or a gen5 swap.



While they are a decent mod.. its really just designed to be a lazy bolt on deal. modded stock rockers make good 15whp gains across the board, but for the cost they are not quite worth it compared to a cam. Roller style 1.9 rockers are basically worthless, and its hard to even see gains out of them. You can easily sell rockers on here for good money which you can trade for a cam.. I have done this in the past for customers before without much hassle.
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Not quite understanding this part.... why would 1.9 modded rocker give gains and roller style one's wouldn't?
If anything should't roller rockers give more gains than modded rockers? Less friction, less deflection...
 
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