DSM/EVO engine positioning

[fostytou]

I've been driving quite a few friends NA cars in my downtime.... and I must say: downshifting is WAY easier with the throttle response they have. Compared to the evos, eclipses, and 1.8ts that I have driven the throttle response for downshifting was amazing. I'm guessing this is a direct result of the long piping before the intake.... correct?

I was thinking.... why did mitsubishi align the engine and transmission the way they did. It seems in our cars there you could eliminate alot of piping as far as a front mount intercooler was concerned if the engine was turned with the timing belt away from the passenger compartment. If the transmission was mounted in the same location (opposite the t-belt with a different design) you could have equal lengnth driveshafts.

now I realize the stock IC is sidemount on our cars... but what else promoted this (and the mirror for the EVO rather than a 90 degree turn)? The only thing I can think are that :
1: the turbo is right behind the radiator... nice and cool
2: if the engine was actually centered, you couldn't put much next to that hot turbo on the passenger side of the engine compartment.
3:the design was older and alot of parts were compatible (but why the mirror on the evo?)

I must admit.... it was really easy to drive the NAs on the twistys... but it killed me as soon as they hit 3k and there was just nothing else.... I don't know if I'll ever go back to anything without a turbo or a fat V8 (....mmmmmm gas prices).

 

[Attack Eagle]

evo has a front mount, and part of the "throttel" response you were feeling is the higher compression making it more responsive at low revs I would suppose.

 

[fostytou]

evo has a front mount, and part of the "throttel" response you were feeling is the higher compression making it more responsive at low revs I would suppose.

I was saying that all of those turbo cars felt like they had laggy throttle response (hopefully a MAF/T will help me with that ).... you tap the trottle and the engine doesn't rev as you are pushing it down.... it takes just a second so you have to guess where you need to push it to.... push the gas and downshift hoping youhit it hard enough to rev match right where you want it and then let off (since you are usually slowing to come to a turn then power on)... that is why I don't do it very often in my car (unless I have time to actually match and slowly engage before the turn)... but it was so easy in at 2002 rs, a scion, an accord, a non turbo jetta and a few other cars I drove recently.

the evo still has a turbo in front and an intake in back.... with the piping going another engine length... which is appears to be about 1/3 the total length.

 

[yoshimitsuspeed]

I was saying that all of those turbo cars felt like they had laggy throttle response (hopefully a MAF/T will help me with that ).... you tap the trottle and the engine doesn't rev as you are pushing it down.... it takes just a second so you have to guess where you need to push it to.... push the gas and downshift hoping youhit it hard enough to rev match right where you want it and then let off (since you are usually slowing to come to a turn then power on)... that is why I don't do it very often in my car (unless I have time to actually match and slowly engage before the turn)... but it was so easy in at 2002 rs, a scion, an accord, a non turbo jetta and a few other cars I drove recently.

the evo still has a turbo in front and an intake in back.... with the piping going another engine length... which is appears to be about 1/3 the total length.

I never had that problem rev matching the GSX. As he said it will be a little laggier due to the lower compression needing boost to maximize power but this shouldn't seriously effect reving it in nn neutral. Try tuning it up. Other than that it will just take you some time to get used to the particular car. By the time I killed my car I could push in the clutch, rev and engage without the tach jumping more than 100 rpm when I let the clutch out. Smoother than the nicest auto. I think it also has a lot to do with the weight of the flywheel. I am driving my girlfriends CRX DX and you can tell the flywheel weighs almost as much as the car. When you rev it it take 30 seconds to hit redline then when you let the clutch out it feels like it has 140 HP for the 3 seconds the inertia of the flywheel is transfered to the drivetrain then it drops down to the 80 or whatever it really has. Remove your balance shafts and get a light flywheel and that thing will rev nicenquick.

 

[Attack Eagle]

of course the intake and exhaust are on the oposite sides of the head...

Better flow and increased head strength and cooling mean it has to be that way... unless you want ot go back to 2valves per cylinder and 1960-70's head technology and no intercooler... it's simple packaging. It has to be that way or else yuo can't get it to fit.


If you are having that much difficulty rev matching on a turbo vs a n/a perhaps tyou are seeingthe diffference in flywheel weight as well.

In anycase I havne't noticed the AWD being any hard to rev match than anything else, though it does not rev to the sky with jsut a simple press of the pedal like most na cars do... perhaps due to lower base timeing than most na cars? (though my wife has no problem going from 1.5 to 3k accidentally as she learns to start a manual shift car in the talon).

That would be the only explanation for why you see a huge difference between na and turbo when revmatching to downshift?

In any case with experince and practice a DSM is no easier or harder to revmatch than anything else, but thro a fidanza on it if it relaly bothers you.

 

[fostytou]

xact... installed
balance shafts... removed


I am on a really grabby clutch (feramic) so that makes things a bit more difficult.... if you don't match well its going to rock you.... and the trans. Its not a huge difference in time or anything... but it is the difference between RIGHT NOW and *snaps fingers*RIGHT NOW. A fraction but in a quick downshift or where you brake->clutchin->gas->clutchout->break and then accelerate out of the turn that tiny split second seems to make things much harder for me. I thought I just sucked for a while... once I drove the NAers that changed my mind. Then I noticed that all the manual turbos I've driven had it, and all the NA ones did not. Driving the other turbos rules out my semi-small clutch engagement area because the evo's is near inexistant.

I'll have to drive a WRX again and see how it reacts with the top mount... Id imagine there was a bit less piping there.

 

[yoshimitsuspeed]

I was thinking.... why did mitsubishi align the engine and transmission the way they did. It seems in our cars there you could eliminate alot of piping as far as a front mount intercooler was concerned if the engine was turned with the timing belt away from the passenger compartment. If the transmission was mounted in the same location (opposite the t-belt with a different design) you could have equal lengnth driveshafts.

I just reread this because it didn't make sence. Are you talking about running the motor front to back instead of left to right? I think you are. If so your nuckin futtz. The front end of the car would be 2 feet longer, 2/3 of the motor would be hanging in front of the front axles killing the already questionable weight distrabution (unless you moved everything else back a foot and the wheelbase a foot longer which the Eclipse deffinately doesn't need). Then getting power to the front wheels would be a nightmare and even more pointless in the FWD version. I just noticed you have a FWD. How many FWD have you seen where the motor runs front to back? It's just not practical in any way. The AWD has equal length driveshafts. If they really wanted the FWD could too. I wouldn't be suprised if you could mod the FWD to take the equal length setup if you wanted bad enough.

now I realize the stock IC is sidemount on our cars... but what else promoted this (and the mirror for the EVO rather than a 90 degree turn)? The only thing I can think are that :

1: the turbo is right behind the radiator... nice and cool

I doubt this really matters much at all. Many cars run turbos on a front to back engine like the supra (I feel like a dumbass because I can't remember if front to back is linear and left to right is horizontal or maybe I am thinking of the subies there, if any one has the right termanology please add).

2: if the engine was actually centered, you couldn't put much next to that hot turbo on the passenger side of the engine compartment.

Same as above. If those chincy little radiator fans can hold up 2 inches away plenty of other stuff will too.

3:the design was older and alot of parts were compatible (but why the mirror on the evo?)

The front to rear setup has been around much longer than the left to right. At least as far as I know. Although since some of the first motor coaches were probably one cylinder I don't know which you would classify them as. Actually since they were chain driven and stuff they probably were in more of a left to right configuration but shortly after that they went to front to rear and I would guess did that untill they started making FWDs. I think Mini Cooper was the first.
As to the second part I don't know the exact years but when the 1gs came out it must have been around the time of the evo 2 or 3s which were the same direction. With the 4 they swiched them. It would be cool if they had done the same with the 2gs just so I could drop an evo engine and tranny in my car but I doubt they saw it worth reconfiguring the DSM.

I should go to bed before my head pops off.

Oh and for your reving problem get an anti lag setup. That should help a little.

 

[fostytou]

The weight distribution is what I didn't think of.... I don't autoX
the wheelbase... maybe I took too long of a look at the 95 5.0 I drove the other day and didn't think about where that transmission was going to (until I fishtailed around a corner )


This was all just a questionable thought in my brain late at night.... Its been rainy so I wasn't nerdy enough to go outside and measure around. Now that I think about it you could probably get away with a similar car length if the bumper was just higher in the front-middle like a 350z. Not that it would solve the other problems or like I'm even thinking about doing this or anything... just gathering ideas on why mitsu didn't.


and I have the anti-lag too.... yay DSMlink! (the maft is a little more daily though... they already hear me coming from a mile away)

 

[crankbender]

We have a transverse mounted engine.

you can't do a fwd realistically with one that is why we have it.

The 350Z does not have a fwd version. neither does a supra or that mustang you were thinking about.

Please don't ask why you have to have a transverse mounted engine on a FWD just think about it for a few and you will figure it out.

Your DSM will rev like any other car for the most part. you just need to tune it or practice.

 

[fostytou]

We have a transverse mounted engine.

you can't do a fwd realistically with one that is why we have it.

The 350Z does not have a fwd version. neither does a supra or that mustang you were thinking about.

Please don't ask why you have to have a transverse mounted engine on a FWD just think about it for a few and you will figure it out.

Your DSM will rev like any other car for the most part. you just need to tune it or practice.

....I was just trying to drum up some discussion and ideas about something I was curious about. Like I said its been raining and all... and you are right it was wrong of me to come up with something radical...those ideas never work.

I'll still swear that there was a difference in throttle response... my car being freshly tuned by AMS.... all of the other cars either stock or professionally tuned. I don't know if this is because of the pipes... but i see no other reason.... someone feel free to close this as it was obviously foolish for me to even think it

 

[fostytou]

I just noticed... the awesome 2.3L '88 mustang turbo was facing the right way