First impression of my i4 from a current V6 manual owner

[seriously]

What I like about this is that I think the I4 will feel faster most of the time and the v6 will feel more engaging more of the time. So instead of saying one is definitely better than the other, it's more a matter of preference/priorities.

 

[Wiz33]

What I like about this is that I think the I4 will feel faster most of the time and the v6 will feel more engaging more of the time. So instead of saying one is definitely better than the other, it's more a matter of preference/priorities.

Yea, I'll take the V6 for a specific drive and the i4 if I'm going on a general trip.

 

[Wiz33]

Finally broke 1K miles on the i4. Nice to see 280 miles left in the tank after 120 mile with half & half between tour and sport. That's how much it usually shows in the V6 after a fillup (well maybe a bit over 300 if I've been running in tour for a bit prior). Now that I can go pass 1/2 throttle in sport. It's quite amazing with sport mode keeping the rev up and you have minimal to no turbo lag when you step on it. The i4 touring suspension is definitely stiffer than the V6, It's probably more like a V6 with sport suspension (maybe even stiffer at rear spring is 140Nm/m vs 115Nm/m of the V6).

 

[Beachbum]

If the I4 Touring is as stiff as the V6 Sport, how stiff is the I4 Sport option?
Anyone have a comparison for that?

 

[Adam Brouillard]

It's unlikely the I4 has significantly different stiffness than the V6. Only the rear spring rates are different. The I4 has a different rear subframe so it probably just needed different pickup points and therefore motion ratios. The different rear springs are probably just what they needed to hit the same target wheel rates.

 

[Wiz33]

It's unlikely the I4 has significantly different stiffness than the V6. Only the rear spring rates are different. The I4 has a different rear subframe so it probably just needed different pickup points and therefore motion ratios. The different rear springs are probably just what they needed to hit the same target wheel rates.

Have you driven both side by side. I basically switch between my V6 and i4 every few days and although both touring. the stiffest is definitely different between the two.

 

[Adam Brouillard]

Not back to back, but I've driven both, and didn't notice any big difference. Significantly increasing rear spring rate only would also shift the balance much more toward oversteer. Lotus would have no reason to do this, just as they would have no reason to have a significantly different ride frequency target between the I4 and V6.

No offence, but I've worked with a lot of drivers and most will say they feel a difference between setups if they have an expectation of what that difference should be. Even if we changed nothing on the car, but said we did, most will say they feel exactly what we said we changed. Using blind changes is a big part of setup testing to remove expectations.

It's possible there is significantly stiffer rear wheel rates on the I4, but unless I see measured data showing this, I'm highly doubtful this is the case simply because it wouldn't make sense for Lotus to do that and the difference in spring rates is easily explained by the different subframes. It's not too hard to measure motion ratios if someone wants to do it when swapping out suspension parts so we can know for sure.

 

[F1 SML8R]

I believe this might be more than just spring rates. As a reminder, the weight split and detailed placement of weight, not to mention the overall reduction of weight, in the I4 vs. v6 is likely what is being felt. I can tell you unequivocally, the two cars, even though they are spec'd with the same suspension, feel materially different. The engine weight and placement alone are likely the biggest drivers.

 

[Wiz33]

Not back to back, but I've driven both, and didn't notice any big difference. Significantly increasing rear spring rate only would also shift the balance much more toward oversteer. Lotus would have no reason to do this, just as they would have no reason to have a significantly different ride frequency target between the I4 and V6.

No offence, but I've worked with a lot of drivers and most will say they feel a difference between setups if they have an expectation of what that difference should be. Even if we changed nothing on the car, but said we did, most will say they feel exactly what we said we changed. Using blind changes is a big part of setup testing to remove expectations.

It's possible there is significantly stiffer rear wheel rates on the I4, but unless I see measured data showing this, I'm highly doubtful this is the case simply because it wouldn't make sense for Lotus to do that and the difference in spring rates is easily explained by the different subframes. It's not too hard to measure motion ratios if someone wants to do it when swapping out suspension parts so we can know for sure.

Go drive it again I have had 3 other Emira owner drove the i4 and without me hinting at the different spring rate. They all thought it's more bouncy compared to the V6 tour. both the front and rear spring are different from V6. I don't have pictures of mine but a friend with a i4 sport have taken picture of his

this is compared to the V6 sport's 60Nmm front and 115 Nmm rear. I didn't know that when I drove my V6 to pick up the i4 and I felt the difference right away. These pictures comes much later.

 

[Wiz33]

I believe this might be more than just spring rates. As a reminder, the weight split and detailed placement of weight, not to mention the overall reduction of weight, in the I4 vs. v6 is likely what is being felt. I can tell you unequivocally, the two cars, even though they are spec'd with the same suspension, feel materially different. The engine weight and placement alone are likely the biggest drivers.

weight different is 12Kg but the M139 does have more weight in front of the rear axle than the V6. The i4 does have shorter A Arms in the rear but there should be minimal impact on spring requirements.

 

[F1 SML8R]

Any time you change weight distribution, and suspension geometry, you are going to feel it. Like you, I've driven both back to back in the same environment and they had different driving characteristics and feel. To me, the I4 was absolutely more nimble, felt lighter on its feet, and overall more balanced. Both were sport suspension cars. I'm simply commenting, because I think the "feeling" difference is more than just spring rate difference.

BTW, the fact that they had to change the spring rates tells you the suspension dynos and suspension sensors that they add for tuning were yielding very different handling characteristics when they were suspension tuning the I4s. no matter how hard they try, they will never be identical simply as a function of physics.

 

[Wiz33]

Any time you change weight distribution, and suspension geometry, you are going to feel it. Like you, I've driven both back to back in the same environment and they had different driving characteristics and feel. To me, the I4 was absolutely more nimble, felt lighter on its feet, and overall more balanced. Both were sport suspension cars. I'm simply commenting, because I think the "feeling" difference is more than just spring rate difference.

BTW, the fact that they had to change the spring rates tells you the suspension dynos and suspension sensors that they add for tuning were yielding very different handling characteristics when they were suspension tuning the I4s. no matter how hard they try, they will never be identical simply as a function of physics.

Yea the numbleness definitely comes from the different front rear weight ratio, the i4 rotates faster/better.

 

[Wiz33]

Not back to back, but I've driven both, and didn't notice any big difference. Significantly increasing rear spring rate only would also shift the balance much more toward oversteer. Lotus would have no reason to do this, just as they would have no reason to have a significantly different ride frequency target between the I4 and V6.

No offence, but I've worked with a lot of drivers and most will say they feel a difference between setups if they have an expectation of what that difference should be. Even if we changed nothing on the car, but said we did, most will say they feel exactly what we said we changed. Using blind changes is a big part of setup testing to remove expectations.

It's possible there is significantly stiffer rear wheel rates on the I4, but unless I see measured data showing this, I'm highly doubtful this is the case simply because it wouldn't make sense for Lotus to do that and the difference in spring rates is easily explained by the different subframes. It's not too hard to measure motion ratios if someone wants to do it when swapping out suspension parts so we can know for sure.

If you do go drive them again. the simplest thing is just find a parking lot with speed bumps and go over them at the same speed. The i4 is much stiffer in the rear.