boomn29

iTrader: (47)

The stock Evo does something like 105-110mph @ redline in 4th I believe.

It seems like a lot of the tracks that I've been to or looked at allow for speeds in excess of this. The problem is once you shift out of 4th gear; you're in a very long 5th that redlines at ~155mph. So, you don't get a good pull beyond 4th really.

There are a lot of other cars that have different gearing and/or 6speeds that don't have this issue that we track with. Most Porsches for example are a gear below us on road courses - where we run a lot of 4th, they'll run a lot of 3rd.

My question:
How do we compensate for this? Just by modding? I can think of a couple ideas:
1) Mod to raise your redline (cam upgrades, springs)
2) Increase hp (more power in 5th)
3) A stroker moter?

I know other cars with similar hp outputs and better top speed gearing will pull away from Evo's on the straights. Hopefully this isn't viewed as a worthless question. It just seems like my car pulls on nearly everybody in 3rd and 4th, but once I'm in 5th there's only so much speed I can gain with AWD and aerodynamics fighting top speed.

Warrtalon

iTrader: (6)

Redline never changes - it's always 7k, so you should re-think the wording there. You can already pull far beyond redline with no changes to the engine, because the stock rev limiter is 7600, most people set it at 7800 when they get flashed, and you can go to 8k without upgraded head internals. Cams and upgraded head internals would make it safer for revving to those levels on a consistent basis. I shift before 7k on the track every time anyway, though, because it's better for the engine. I only shift above 7k when drag racing.

You also need to specify between an VIII and a IX. The VIII can go a lot further in 4th than the IX, but 5th gear is a dog in the VIII and pretty good in the IX. What I have is an VIII 5spd that has a tall 4th, but then it has 5th gear from a IX so that I don't have much of a weak spot in that area.

A stroker would give you less useful revs, which would make 1-4 very short but make 5th more useful. I'm not sure that would be the intended effect, though.

Yes, another limiting factor is aerodynamics. We simply aren't good at accelerating above 100mph.

ryan0

iTrader: (2)

i think he's talking about the big gap between 4th and 5th..

the only real answer is, you switch your gearing.. just like on playstation.

or run shorter tracks.

Warrtalon

iTrader: (6)

yes, I know, but the gap on his IX is much different than the gap on an VIII - they have completely different gearing. The IX 5spd has almost identical gearing to the 6spd in gears 1-4, then it has a single gear to cover 5th and 6th, which kinda sucks. However, the VIII 5spd has much better gearing through the end of 4th for road racing but then a tall overdrive in 5th. That's why I have a built VIII 5spd with 5th gear from a IX. There is not much of a gap between 4th and 5th, thusly.

evo637

I've only really used 4th at every track I've been too. There's no need to switch to fifth, not enough time..The last time I've checked my speedo on the straights of Thill it was around 118-120 pass 7k. You might just put a bigger turbo if your looking for more topend speed..

Ludikraut

iTrader: (17)

A stock Evo VIII would do ~121mph in 4th gear at 7500 RPM (assuming stock tires). Not sure if the IX 4th gear ratio is different, but it should be very close to that number.

I run an AMS built 2.0l block with an upgraded valvetrain. Fuel cut at 9100 RPM, which comes out to ~146mph in 4th. One of the main reasons I chose to build my car the way I did was to allow for a wider powerband and higher RPM so that I don't have that extra shift in short straights, and I don't have to go into 5th gear unless I'm cruising on the HWY.

l8r)

nothere

iTrader: (23)

that is fantastic Ludikraut.


boomn29
I suppose your right about the lack of acceleration in fifth. For a race you may well need a shorter fifth.

For the rest of us wannabees the braking zone is coming pretty quick anyway.

Warrtalon

iTrader: (6)

Ludikraut, as I mentiond, the 4th gear in the IX 5spd is MUCH different. I said it twice, then you said "but it should be very close to that number." It's not close to that number.

boomn29

iTrader: (47)

I've used 5th at every track I've been to.

For example at Putnam Park, I would near 7k in 4th on 2 of the shorter straights, and need 5th for the main. GPS had me doing 122mph top speed if that helps anyone. I know at Gateway in STL, I could hit 125-130mph if I push it. I'm not 100% sure what speed 4th @7k is in my car. I've broken the habit to watch the speedometer!

Yep, I could push the car to 7500rpms I know, but I'd rather not repeatedly on the track for longetivity reasons on the stock valvetrain. Also, from looking at my dyno sheet, my power starts to fall off pretty good after 6500rpms.

Yep. And your comment about the braking zone is very true! But there's only so many spots for point-by-passing and the main straight is always one of them!

Ludikraut

iTrader: (17)

I guess that depends on your definition of MUCH different, doesn't it?

VIII 4th gear ratio = 1.031:1
IX 4th gear ratio = 1.096:1

Both have a final drive ratio of 4.529:1

VIII 4th gear @ 7500 RPM = ~121 mph
IX 4th gear @ 7500 RPM = ~115 mph

The practice of bumping fuel cut up to 7800 RPM would get an IX to 119 mph, and at 9000 RPM it would do 137 mph in 4th gear.

l8r)

Ludikraut

iTrader: (17)

Boomn29, at 7000 RPM your IX should be right around 107 mph, if you're on stock tires.

l8r)

boomn29

iTrader: (47)

Yep, that's what I found. On stock tire 4th @ 7000 is only 106.9 on the IX. So, I obviously need 5th gear on the tracks I'm running!

Found this:
https://www.evolutionm.net/forums/sh...0&postcount=18
So, now that we have settled the top speed of a IX in 4th gear; I guess we're back to the main question. Sounds like the easiest way for me to compensate would be to fortify my internals so I can safely rev higher in 4th. But still, a top speed of ~120mph isn't going to be enough for all situations and that's if I pushed it to 8k.

Therefore, I guess I'd be looking at a potential big power upgrade - but that's not an option I want to look into. I don't have the $$ and I love the fact I can beat on the car now and everything is safe.

Suppose I could research what Warralton did with the gearing upgrade, but that sounds pretty substantial.

Warrtalon

iTrader: (6)

Yes, Ludikraut, I consider that a significant difference. It's especially apparent on track.

Boomn, I don't think removing your trans to put in a 4th gear from an VIII would be worth the cost. The actual cost of changing the gear isn't that much, but removing the trans, shipping it to Shep, getting it back, and re-installing is a lot of hassle that only makes sense when changing the clutch or if the trans needs to be rebuilt for other reasons.

You could do head internals with cams and more safetly rev to 7500 without as much dropoff in power, I think.

boomn29

iTrader: (47)

Thx.
Pretty much what I figured the answer would be. Dump the money into cams and upgraded springs/retainers would make the most sense in this situation I'd think.

Just wanting to see what others do on roadcourses where 5th is needed.

thatguy

iTrader: (5)

Use a 245/45-17 tire and you should hit 120 mph @7800 on the IX and 123 @8000.

Are you going to use the stock advans or do you have a dedicated track/tire set?