1g non turbo cams better then 1g turbo cams?

[90laserRSfwd]

BrianCrower.com - Brian Crower - BC - Mitsubishi Elipse / Eagle Talon - 4G63

According to BC, the non turbo 4g63 has a better set of cams then the turbo car. I'm not sure I should use the word better but the duration is longer and the lift is higher. ?? Can anyone confirm this? Or at least prove that is it false? I can't find info on 264 cams but from memory, the stock N/T cams are pretty close to mirroring 264's....

After going on extremepsi's website (looking at comp 101100's) it seems like the N/T's are a slight upgrade over the turbo cams, and the 101100's are a little better then the N/T's. Anyone have a spare set of N/T cams to test?

 

[90laserRSfwd]

stock non turbo accroding to BrianCrower.com - Brian Crower - BC - Mitsubishi Elipse / Eagle Talon - 4G63 (8/22/08)

Dur @ 0.050 Lift (") Lift (mm)

208°/204° .365"/.349" 9.27/8.86

comp 101100 cams according to EXTREME PSI : Your #1 Source for In Stock Performance Parts - Comp Cams Serious Street/Race "101100" Camshafts: Mitsubishi Eclipse 90-99 (8/22/08)

204°/204° .407/.391 Unavailable

 

[dsm-onster]

The turbo cam profile they are listing is the A/T profile. The N/T profile is NOT "better" than the M/T turbo profile: which is 252/248. The M/T turbo profile after 1991 has both cams at 252 duration. No dsm cam has 256 duration. . . So the website is just wrong about that.

The A/T profile is better for an automatic car than the m/t profile and n/t profile. Less duation is needed to get that off the line oomph.

Also there's alot more to cams than whay they list. For example M/T cams have more total cam advance. And theyy also have more overlap. This will give you lots of boost early but you'll fall on your face up top. Yet the "smaller" turbo a/t cams, which is listed there, will keep pulling. The overlap and advance has a great influence on power range for a turbocharged motor.

And there is NO 264 cam that mirrors ANY stock dsm cam. The duration is different, the ift is different, the ramp is different, the total advance is different, and the overlap is different. . . Where are the similarities?

 

[90laserRSfwd]

I didn't mean to get into a war or lead people to the wrong conclusion. I just saw what I liked to in my post and was wondering what was going on. PM sent.

 

[Freerevving]

Yeah he's right the n/t cams have a little too much overlap for the amount of lift... good for a NA high revving engine, but kills some torque on forced induction

and.... I don't think those specs are right...

I have read the correct specs somewhere, and only one of the cams are better on the n/t's, I believe it's the intake... but the duration crossed with the lobe speration isn't that great for turbo (in the lower rpm's)... A good way to gain some bargain hp but not worth the loss in drivability for the small gain... Turbo 4 bangers cooperate better with less overlap... If you degree the cam I'm sure it would make a decent upgrade.

also, according to a friend at TOTAL in Dallas, some factory 4g63 Turbo cams have better profiles.... I don't recall exactly, but I think he said the ones with "O"s or "A"s embossed on them... okay I'm not really sure which ones, and I don't mean to start rumors, but he's measured cams straight from the Mitsubishi parts counter and claims there are 2 different cam profiles for 90-94

 

[dsm-onster]

I didn't mean to get into a war or lead people to the wrong conclusion. I just saw what I liked to in my post and was wondering what was going on. PM sent.

War? where? I wasn't bashing anyone. . . We're not perfect. Others know things. I know things. We add them all together and have a forum. Brian Crower Company is a good companyand their cams are great. Their single sprigns are even better and their prices for what you get are the best.

The best cams are the 1993-1994 turbo cams. Least overlap which helps up top for more peak power. Most duration, 252 on both cams, which also helps up top for more peak power. And the highest lift.

 

[Freerevving]

The best cams are the 1993-1994 turbo cams. Least overlap which helps up top for more peak power. Most duration, 252 on both cams, which also helps up top for more peak power. And the highest lift.

Okay then for me it's confirmed.... thanks ... I'm remembering more of what Red told me: IIRC he said that almost all 93 and 94's had the cams and some 91's and a lot of 92's had them as well... and I can't remember what he said to check for (for example "o"s or "a"s embossed on them)... but if it isn't a 90,93, or 94 that it's worthwile checking

btw more overlap is better up top, less overlap is better down low.... Turbo's like less overlap in general... but when you start getting into rpm's ranges higher than stock, the engine works more efficiently with a little more overlap... which, btw, is usually achieved by increasing the duration and not the lobe speration... and of course there are many variations of this, as only R&D can truly make a cam perform well

 

[dsm-onster]

No. Someone racing a naturally asperated engine or a supercharged engine told you this. . . More overlap is ok when you have less back pressure. N/A cars can do that easier, Supercharged engines, always by default. Turbo motors are different. If you plan on pushing your turbo, you MOST CERTAINLY will have more exhaust backpressure than intake pressure. With overlap, you'll be pushing exhaust gases into your intake and lose volumetric efficiency in the upper rpms. Period. FP2X cams are FP3 cams with less overlap. They do better for highr revving 2.0L motors. That's why the fp3 cams are for strokers.

 

[Freerevving]

No. Someone racing a naturally asperated engine or a supercharged engine told you this. . . More overlap is ok when you have less back pressure. N/A cars can do that easier, Supercharged engines, always by default. Turbo motors are different. If you plan on pushing your turbo, you MOST CERTAINLY will have more exhaust backpressure than intake pressure. With overlap, you'll be pushing exhaust gases into your intake and lose volumetric efficiency in the upper rpms. Period. FP2X cams are FP3 cams with less overlap. They do better for highr revving 2.0L motors. That's why the fp3 cams are for strokers.

For one, I already said Turbo engines are different, secondly I already said that they like less overlap than N/A

So far, I see nothing wrong with my statements...

FP's clearly have more overlap (between .010 and .030) than stock.... there are too many factors in engine timing that decide how much duration is best at a certain lift, but in general (as in the graphs) more lift will have more overlap

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I believe that the FP2x's have almost the same overlap as FP2's because of R&D, and they found that it works better... but they both have more overlap than stock...

You always want more overlap with a stroker! you can get away with it!... the torque increase means almost nothing if you can't turn it into a a level power curve... besides, you can only make the ramp angle so sharp at a certain timing, without having more overlap

As I said before, R&D eventually decides what works best with a certain cam profile, it's obvious that FP/Comp has done a lot of it.

 

[dsm-onster]

Are you discussing how much higher the valves areduring overlap? Because the number of degrees between the open of the intake valve and the close of the exhaust valve appear the same in the cam profile graphs there. But, in fact, if you look closely, you see the stock intake cam open earlier and the stock exhaust cam close later.

To calculate overlap, "Add the opening number of the inlet cam to the closing number of the exhaust cam".

 

[Freerevving]

...the number of degrees between the open of the intake valve and the close of the exhaust valve appear the same in the cam profile graphs there. But, in fact, if you look closely, you see the stock intake cam open earlier and the stock exhaust cam close later.

The degrees of overlap are the same... which already dicredits the theory that larger cams have less overlap, well, at least for FP's.
The colored lines are on top of each other only so we can see them... commonly done in graphing programs. They appear to begin and end at the exact same spot. But, I don't totally agree that the degrees of overlap is the amount of overlap

Are you discussing how much higher the valves areduring overlap?

Yes:

FP's clearly have more overlap (between .010 and .030) than stock.... .

... the physical area between the lines is much larger, and shows more overlap. In comparison, the valves are practically closed during most of the overlap on the stock cams

More overlap is usually only effective for volumetric efficiency at higher rpm's, where the valves are moving faster than the air... again, turbo engines have a hard time with too much overlap mainly because it slows down the turbine, and also because the intake air is under pressure, it's moving a lot faster than "suctioned" air, so the valves get to be more accurate with timing. Regardless, even turbo'd engines can use a tad bit more overlap at high-rpm because the valves and pistons are moving a lot faster

Generally speaking, a set of cams with less overlap will generate more torque, while a set with more overlap can be useful for generating HP. Even though Piper's website doesn't mention lift during overlap, it does mention "In general terms the larger this number or the greater the overlap, the hotter the cam."--(Piper Cams) Most people will stay away from too much overlap when turbo-ing an engine

 

[dsm-onster]

Yes, higher duration usually DOES increase the overlap. This is why FP separates the lobe centerline more. To counter the inadvertant increase in overlap.

I truly didn't say high performance cams have more, less or the same overlap. I said that fp2x cams are fp3 cams with less overlap. I did say adding overlap does cause a drop in topend power with a turbo car no matter the cam.

Valve height during overlap is not as important as total overlap duration because we're dealing with a pressure differential often times over 2 between the intake and the exhaust. I am confused as to why you're discussing naturally asperated flow characteristics with a turbo application, such as the above. And also, overlap assists VE or flow in higer rpms is an n/a characteristic. I understand. But since the cams discussed are not n/t cams, none of this applied to the conversation. More overlap than stock in a turbo aplication will speed spool and lose topend. I've played with cam gear timing enough to know this. You have to pay attention to your overlap when looking for more topend, since increasing duration to gain topend will actually work against you because more overlap will develop. So there needs to be more cam lobe spread. Hence, the wide spread of the fp2 and fp2x cams was dialed in to keep the overlap as close to stock as possible. I've retarded my fp2x exhaust cam and added overlap so that the set effectively becomes a pair of fp3 cams, and my airflow after 6K planed off earlier vs. climb as when installed straight up.



Per the factory manual, the 1993-1994 factory turbo m/t cams have an intake valve opening at 21* BTDC and an exhast valve closing at 15* ATDC. The overlap duration is the sum of those or 36*.

The Comp Cams cam card I have for my fp2Xs show an intake valve opening at 27.5*BTDC and an exhaust valve closing at 9.5*ATDC. This sums 37* total overlap duration. Hardly more overlap, don't you think? The above profile graph of factory cams is of the A-A factory non-turbo profile: Intake @ 26*BTDC and exhaust @ 9*ATDC which is actually the same overlap duration as turbo cams. But there is more total cam advance and and less exhaust duration for the n/t cams. I don't constitute 1 degree of difference in overlap a very large difference. If overlap helped up top with a turbo application then where's the extra overlap. A boosted motor will respond very noticably to high lift overlap and lower lift overlap. A turbo charged motor will always see an adverse effect. Unless pressures are equal, then none at all.

So, valve overlap is a negative side effect of increasing duration for a turbo motor. This is why 272 style cams work so well for a broad range. There's enough duration for good topend, but there's not so much duration that lobe spread has to be extreme. This is also why cams like BC 280s and moreso, 288s, do well for some and worse for others. The guys pushing their turbos with undersized turbines are seeing too much backpressure with the overlap that HAS to be there for the big duration cam to run properly. The only way to get around it would to spread the centerlines too far apart to be in good time. If you have a borg-warner or holset or gt35r+ or smilarly more efficient turbine, you're seeing backpressure much closer to your boost in psi. That overlap doesn't hurt you then. Yet, to reiterate, it still won't benefit; because the pressures are at BEST equal between the intake and exhaust. So there's no way that the overlap can help suck the intake aircharge into the cylinder, which is why someone would want more overlap. But at least it won't be hurting you with those properly chosen wheels for the intended goal.

For the rest of us, we're not going to see that. So overlap hurts topend. It can't help very much no matter how well you've chosen a turbine, unless backpressure is lower than intake pressure. And when is that the case at 6K or more?

A little side: HKS 272 cams have more overlap than fp2 cams but fp2 cams have been proven to deliver more topend. Fp2 cams have less advertised duration and less duration @ .05".

 

[Freerevving]

Yes, higher duration usually DOES increase the overlap.

that's what I've been saying the whole time

I didn't say high performance cams have more, less or the same overlap.

well, you certainly implied it

. Least overlap which helps up top for more peak power.

^ was the only reason for my initial response

If more overlap helps a turbo car in the higher rpm range then why isn't there more overlap with fp2 and 2x cams

as opposed tho the fp3? I would guess that the stroker needs more help in the top end for the engine to feel balanced, and the "square" lobes prevent less overlap from being efficient. The 2L must have help in the low end to feel balanced or "streetable"... the exact reason I'm exploring the limits of 264's right now.

HKS 272 cams have more overlap than fp2 cams but fp2 cams have been proven to deliver more topend. Fp2 cams have less advertised duration.

I would like to see a comparison graph, if available, as I know that HKS have better power before 4750rpm than most every other cam out there. Even so, more degrees of overlap can be easily offset by shorter duration and less lift during overlap. I would bet that less air is moving during overlap with the HKS.

Advertised duration means very little.... the overall cam profile, lift, duration, and overlap is added up by the manufacturer, and then they decide the "advertised" duration. They decide this because the amount of air moving during the actual duration is offset by the lift at certain degrees of rotation, and also offset by cam advance and overlap.

Any mix of these ingredients can make a good cam or a bad cam... the only thing I claimed is that in general more radical cams have more overlap... btw 1 degree of overlap can make a considerable difference depending on air velocity... but I agree that it's of little concern at high rpm's

 

[dsm-onster]

as opposed tho the fp3? I would guess that the stroker needs more help in the top end for the engine to feel balanced, and the "square" lobes prevent less overlap from being efficient. The 2L must have help in the low end to feel balanced or "streetable"... the exact reason I'm exploring the limits of 264's right now.

Well from my logs and personal experience. I retarded my fp2x exhaust cam which increased overlap, and lost topend. I gained midrange, and low end spool speed and response. 2*,4*, 6* it just got worse up top and the mid range just got stronger . . . Sounded mean a he!! though

Same thing occurred with my stock cams.

Again overlap doesn't help suck in air when the pressure differential is in favor of the exhaust. A twinscroll turbine housing with a true divided runner exhaust manifold will see less loss up top with more overlap because the pulses are separated and the pressure differential is neutralized to a higher rpm/flow.

 

[Freerevving]

Ah I see exactly what you're saying...
theoretically that shouldn't happen... but I've seen it a million times where theory doesn't always work with camshaft timing. It's impossible (to my knowledge) to measure exactly what the air is doing when the engine is running.. R&D usually moves against classic theory

The overlap is probably at it's limit at that duration and lift... the air is losing velocity with more overlap and intake pressure might be helping the turbo spool...a good way to increase your top end would be to retard the intake cam in slightly smaller increments (almost the same degree) along with the exhaust... You might try 2*Ex and 1.5*In... or even 2 and 2 if it's most effective with the ramp angle... a lot of times this can be too much if the cams are dialed in for the top end already

I've seen a lot of people go shorter duration on the exhaust cam (non-dsm turboed engines) with amazing results... I'm wondering if anyone around here has tried a 272I/264E or 280I/272E combo. Average hp above 5250 is more important than peak hp.

 

[dsm-onster]

We're getting each other. This is a good discussion. I'll try that. I've been wanting to. But I have too much topend for my stock tranny as is this year. even with the stock intake manifold. I think there are gains with more total cam retard running fp2x cams. The more aggresive ramp rate kind of "fools" the air into thnking duration is more, IMHO, since the valve is open higher earlier like with a broader duration lobe. So I think they can get away with being dialed in for more up top, since duration needs to, in a sense, match your rpm range (or air velocity).

I've also wanted to try the n/t intake cam with a manual turbo exhaust cam. This will be like running the turbo intake cam advanced. It will dial in about 5 degrees more overlap. This should give some incredible midrange and early rpm boost response. An A/T car could benefit from this. Running a typical 14b upgrade in the auto (vs. the tiny stock 13g), stock intake manifold, more aggressive stock auto timing map, plus the stock stall; All lends to running more total cam advance which will go up with the intake cam being more advanced. Also all those components would work better with the fastest spool you can get. 5* more overlap should noticably increase spool speed. It'll die up top after 6K, but who cares, you have a 14b turbo and a stock intake manifold anyway . It would make for a torquey street setup of which a typical turbo auto car doesn't have the feel; or great budget automatic autox car. Besides, the n/t intake cam is an upgrade to the auto intake cam in more duration and more lift.

 

[Freerevving]

The more aggresive ramp rate kind of "fools" the air into thnking duration is more, IMHO, since the valve is open higher earlier like with a broader duration lobe. So I think they can get away with being dialed in for more up top, since duration needs to, in a sense, match your rpm range (or air velocity).

yeah I totally agree.. the aggressive ramp angle, the "square" lobes, have probably lost a lot of air velocity just before overlap... making a little too much overlap very bad... you might be able to find gains with a small amount more, if retarding the intake at the same time.

I've also wanted to try the n/t intake cam with a manual turbo exhaust cam. This will be like running the turbo intake cam advanced. It will dial in about 5 degrees more overlap. This should give some incredible midrange and early rpm boost response..

I don't know... Is the intake cam that much more advanced? I know there's more overlap, which is probably part of the reason the n/a 4g63 seems to be dead under 4500rpm.

I wanted to play with the intake cam at one point... but was discouraged when a guy from Houston (that had done it with both n/a cams) said it makes the engine "fall on its face". He claimed it only had power above a certain rpm and wasn't that great for driving. Same guy who has been selling this rear end for several months: dsm 4 bolt rear eclipse talon 1g used to be $450

I still wanted to play with just the intake cam because the n/a exhaust cam has less lift, but I've kinda given up on it. Do you plan on testing it?? because I LOVE knowing the cheap/free mods!!!

 

[rhamlinii]

yeah I totally agree.. the aggressive ramp angle, the "square" lobes, have probably lost a lot of air velocity just before overlap... making a little too much overlap very bad... you might be able to find gains with a small amount more, if retarding the intake at the same time.



I don't know... Is the intake cam that much more advance? I know there's more overlap, it's part of the reason the n/a motor seems to like 7000rpm.

I wanted to play with the intake cam at one point... but was discouraged when a guy from Houston (that had done it with both n/a cams) said it makes the engine "fall on its face". He claimed it only had power above a certain rpm and wasn't that great for driving. Same guy who has been selling this rear end for several months: dsm 4 bolt rear eclipse talon 1g used to be $450

I still wanted to play with just the intake cam because the n/a exhaust cam has less lift, but I've kinda given up on it. Do you plan on testing it?? because I LOVE knowing the cheap/free mods!!!

I know it's been said that turbo profiles should be a certain way for a long time. Alot of the fastest hondas are now using all-motor cams. Truth, the more power you make N/A. The more power you'll make pound for pound with boost, aslong as the compressor will keep up with the demand flow of air. That goes for supercharged, or turbo setups. I'm not saying they're right to use those cams, but it's true. Cams do alot more then decide top-end power, and some cams are just made for different setups altogether (Stock to wild). It's all about "your" power band, and everything plays a factor into those numbers. I'd be kind of curious to see what Shep's and Rau's car makes on the motor with no boost and what cam's they choose. I use 272/272cams in my car, that are degreed a bit. I read in Drag magizine, Sean Glazer went gained something like 100 awhp from a cam swap, and he explaind why. Danl trapped 122 with a 14b without nitrous, in a somewhat full weight street car. I believe he was using the FP3 cams. People were telling him not to, because he was just running a 2.0. I thought it was pretty impressive, and sometimes people are wrong. The FP cams are what works now after they played with what works the best. HKS never dreamed we take the 4g63 to 10-11k, stroker motors, or we'd have the spring profiles we have now. Look at FP valve springs, that's the true secret of there cams. I'd never run anything but, if I had to have those cams. If you stick to the power band that HKS designed them for. HKS 272/272 are still some of the best cams on the market. They are one of the few cams that work with you stock hardware. Years after they stopped making them, people are still asking for them. To answer your oringnal question, try them both and see.

 

[dsm-onster]

I don't know... Is the intake cam that much more advanced? I know there's more overlap, which is probably part of the reason the n/a 4g63 seems to be dead under 4500rpm.

I wanted to play with the intake cam at one point... but was discouraged when a guy from Houston (that had done it with both n/a cams) said it makes the engine "fall on its face". He claimed it only had power above a certain rpm and wasn't that great for driving. Same guy who has been selling this rear end for several months: dsm 4 bolt rear eclipse talon 1g used to be $450

I still wanted to play with just the intake cam because the n/a exhaust cam has less lift, but I've kinda given up on it. Do you plan on testing it?? because I LOVE knowing the cheap/free mods!!!

Yea the n/a intake cam has more advance but also more duration than the stock automatic turbo intake cam for al 1g years. The n/a exhaust cam and the automatic turbo exhaust cam have identical duration and advance for all 1g years.

So swapping in the n/a intake cam on an automatic turbo car is all that's needed to turn your pair of cams into n/a cams. The n/a intake cam also has more lift. Considering that the n/a cam has more duration, it may not fall on it's face vs stock shorter duration automatic turbo cams. . . But the n/a cam still closes the intake valve earlier because of the large amount of cam advance. This is never good for power up top.

I'm saying that running an n/a intake cam might be a good mod for a 1g automatic. . . If you want a super fast spool and early powerband where you don't care about past 6K, like rally, running the n/a intake cam with the m/t turbo 1993-1994 exhaust cam may be for you. But, I was primarily looking at running the n/a cam as an upgrade for the tight duration and very little overlap.

I'll be trying it though since I have an n/a head apart in my ched and my brother has a good running automatic AWD car in which we found an eprom . If it cose with an eprom, it was meant to be modified. It's DSM destiny.


-----------------
Keep in mind Dan Loncher's car was FWD and his weigh came in at 2700ish lbs. 128mph with a 3200lb awd would have put his setup at well over 400whp . But yea, he didn't listen to the masses and did very good. In fact, the highest hp based on trap speed and weight on record for a 14b. Interestingly, his ET and MPH went up when shifting earlier. FP3 cams have a bit more overlap because the exhaust cam is about 3-5 degrees retarded vs. straight up FP2X and fp2 cams.

 

[Freerevving]

Intrestingly enough... Comp markets the FP3x's as 101400's and as a Race profile... doesn't mention strokers AFAIK... Strokers already have a quick spool, I think the extra overlap doesn't hurt them... But as long as your launching at 7000 and your rpm's never drop below 4500...

as far as n/a cams to f/i... I've only compared the manual transmission ones, using stats... and I'm going on memory here. It might help if I actually look at a comparison again.
IIRC, The intake of the n/a looks best matched to the exhaust of the manual f/i... I remember the main thing I was looking at was lift and lobe centers.

I still feel any N/A profile will hurt turbo spool, as it does on high-revving hondas and others... If they were running 7.8:1 compression I have a feeling their engines might "fall on their face"...
It might be that the 4g63 n/a intake profile won't work perfectly in the low rpm's unless properly degreed... but we won't know unless you try

I know it's been said that turbo profiles should be a certain way for a long time. Alot of the fastest hondas are now using all-motor cams. Truth, the more power you make N/A. The more power you'll make pound for pound with boost, aslong as the compressor will keep up with the demand flow of air.

I agree with you 100%, but you run into major drivability issues with wild n/a cams and turbo... a lot of those guys (the intelligent ones) will opt for the cams with less overlap and more advance... the rest (not so fortunates) will go for the sudden burst of power that loses races.

 

[dsm-onster]

... the rest (not so fortunates) will go for the sudden burst of power that loses races.

. My brother keeps nagging me concerning his automatic DSM, "I want that sudden surge of power and I want it early. . ." I tell him it will FEEL good, but that's about it.

 

[90laserRSfwd]

So we all agree that the N/T cams are infact not "better" (dare I use that word) when in comparison with factory A-A camshafts correct?

 

[dsm-onster]

Factory A-A cams are non-turbo cams. Why FP chose those cams as a comparison to their turbo cam upgrades, who knows? Automatic turbo cams are the worst imho. The lowest duration and lift. The best are 1993-1994. these have 252 duration and the highest lift. They also have a good balance of overlap, that seams to increase spool speed in alost every case. But which apparently more overlap than those particular stock cams takes away topend with 252 up to 272 duration for most of us, because we all tend to run tiny turbines for fast spool and a big compressor thinking a big flowing compressor will negate the little turbine . . .

 

[ilikerice]

I am gonna rez a thread here, Im a newbie to the DSM world but need a bit of info.

I currently have a N/A 4G63 1G head with a 2G block on my current setup.. Now, I was convinced by a local DSM owner that the N/A cams I am using will not run the car right and will misfire and bog down. So I bought his old turbo cams from him. Which was a good deal. $80 for a good (no shaft play) 16g and turbo camshafts. The turbo alone was worth the purchase I feel.

Well, I just mentioned this in a random thread here and someone else was telling me that using the N/A cams wont make a noticable difference. I may loose a bit of hp/torque. I understand the fact that the turbo cams will perform better, but thats not my goal at the moment. Right now, I just want this thing drivable. After I get it able to drive down my street, I will then consider swapping out the cams.

Can I at least run the N/A cams without serious issues?