Two faced insight build underway. K series gearing? discuss
 

So If anyone here has seen my random and sometimes spastic posts I have reset a few things and Im starting from almost scratch on my build... Here is what I have so far...

2002 Honda Insight

Goals.... Ultimate Commuter (not a daily driver, but goals are goals)

Actual goal, to drive 100 miles to the drag strip and average 50+ MPG and without touching a thing run a 10 flat in the 1/4 mile, car will have A/C, P/S and a nice stereo, big brakes, nice paint, wheels, etc.

K20A2/A3 hybrid motor... 11.7:1cr
K20A2 block-stronger, oil squirters, higher OEM compression pistons
K20a3 head- smaller exhaust ports, smaller combustion chamber
ARP head studs
K24a4 intake manifold
Garrett GT2554R/HKS turbo manifold (will most likely change)

Rear end is out of the 2016 HRV and I just ordered hubs and will have it mounted soon

Now for the transmission. I have the trans which is Element AWD (with Accord outer case to fit Insight), gearing inside is stock Element and Im really at a loss on ideas that don't include trial and error (which I will ultimately do).

Element gear ratios.
1st: 3.533

2nd: 2.042

3rd: 1.355

4th: 1.028

5th: 0.825

FD: 4.765

Options add 6th .659 (about $650 in parts!)
4.4 or 4.0 FD
aftermarket LSD

3.533 to 0.659 is just about the biggest spread within the k series gears

This is not cheap and asking about gearing in the K20.org etc groups is tough when talking about anything but drag racing (hey, its AWD, I get it)

I can also buy a 2015 Civic Si to harvest for its 1-6 (or 3-6) and LSD (which can be machined to fit for $300) about half the cost of the above option

2015 Si
1st: 3.267
2nd: 2.040
3rd: 1.429
4th: 1.073
5th: 0.830
6th: 0.647
FD 4.765

So I thought I would ask you guys your opinions on these gears.

tire size is still up in the air, Ive been looking at everything from 205/50R15 ultra performance summer tires to 215/45R17 in these https://www.toyotires.com/tire/patte...es-versado-eco

So this aint about saving money or the environment, just a fun car to build with lofty goals which I may or may not achieve but I'll have a nice sound system. Thanks for any tips, comments, suggestions, humor, etc.

Some disordered thoughts:

Complete kit for a 2012+ Civic Si 6th gear cost me around $200 new.

The Accord transmission has the best ratios out of the box, with a 4.4 FD and 0.659 5th gear.

TSX box has nice ratios after you swap the final drive but the magnesium casing is more fragile and not appropriate for high boost and sticky tires.

To my knowledge the Accord and TSX casings are identical, and internals can be interchanged.

I have no idea about AWD or differentials. An LSD did a lot for my car's traction.

4.0 FD from the Euro Accord is the tallest factory FD. I had a 3.4 made by Frana Motors, cost was about twice that of a new 4.0 FD.

Don't get too far from the Insight's stock offset or dimensions or you'll start to have weird effects on handling. 195/55r14 with a really sticky rubber would probably be my choice for the drag strip.

Edit: For what it's worth, even a 3.4FD and 0.647 6th gear could be taller in this car with a stock K24A2, it climbs mountains easily in top gear, no shifting at all. I would hate to have lesser gearing. Thinking of upsizing to 185/65 65 or even 70 aspect ratio to bring it down further.

I will be watching this post for sure. I like your goals and hope you hit them.

Whats the pic of?

Love this idea.

I'm guessing that you're planning to tune the ECU fuel maps so that you can run really lean at part throttle at freeway speeds. And then have it simultaneously set up so that at wide open throttle you can get the kind of power and performance that you want for the drag strip. To get the fuel economy in those lean AFR conditions on the freeway you're definitely going to want taller gearing than the options you're describing. If you can get that .647 6th gear and the 3.4 FD that Ecky is describing you'll have really remarkable freeway cruising RPMs.

If you don't want to touch a thing once you reach the drag strip, I think you've got some aerodynamic issues to consider. I would bet that the Insight stock body shape is stable enough at the speeds you'll hit in 10 seconds on the quarter mile to be safe, but you'll want to be sure. The lift reducing things that you might do to enhance stability at a hundred miles an hour would have negative effects on your overall drag on the freeway when you're trying to run at part throttle and get 50 plus miles per gallon. Just some things to consider, if you're not doing so already.

Sounds badass. Can't wait for photos.

Question first....

The 2012 6th was more than just the 2 gears but the parts needed to add them to your accord 5 speed?

"Let me get this straight" question...
With a (stock?) TSX Engine you're yearning for a 24" (185/70-14) tire along with your 3.4FD/.647-6th? What is the perceived effect on first gear?

I will be raising and widening the strut towers, building custom control arms and widening the front track to match the rear. HRV rear track is 62" front will be 60". RSX coilovers will go in all the way around.

The picture is the HRV rear sitting under the insight.

Just about all aftermarket K diffs are now available in AWD trim as its just a slight difference in tolerances due to the drive ring. If you already have a stock LSD you can pay about $300 to have one machined but not worth buying new since you can buy a Wavetrac for $699

One "AWD K FACT" is "AWD K TAX", this stuff is VERY popular and I have actually decided on one upgrade that this crowd WILL like. I am going to keep the swap as we are talking about it just as it is except FWD however the rear instead of being driven by the engine will be driven by this...

https://www.evwest.com/catalog/produ...asfsivmri2q8o7

I figured (and I know very little) that I could add this in the mix for $10K (or hopefully well under) again, not 100%, or even 10% sure how good it would work but would be very cool, my wife absolutely loves the idea of making the insight a hybrid again even if it just by definition. Since there is no conversion (heater, A/C, 12v, etc) going on it would be rather simple. I can sell my AWD trans and buy more than all the parts I need for the FWD stuff. I can also keep my gas tank where its at. ;)


A note on my engine, even though its a K20, cam and intake manifold is same as k24a4, compression is 11.7:1, the turbo is tiny and BB (GT2554r) and the idea was to make it have a K24 (K26?) feel but having driven both K20s and K24s there is no doubt you can feel the smoothness/lightness of the k20 over the k24 which can only be a good thing when cruising.

KPro V4 w E85 sensor is in for sure, will also be open loop lean burn for sure. Looking at staged injectors/bi fuels (87/E85/CNG?) but remembering this is a hobby and and expensive one so all in good time. Keep in mind if and when gas his $5 or even $10 per gallon all this crazy talk ain't so crazy. I had a K24A2 EP3 with zero eco interests until it was a $50 fill up every 3 days, it's how I met y'all.

I started with a TSX box so it was a straight swap. I'm uncertain what's missing from the Accord box.

Right now when I get on the gas it breaks the tires loose on a warm dry day in 1st even if I ease into it - that's with around 170ft-lbs of torque. Admittedly I'm not running sticky tires, but I'm also running little more than a base map and that's with an LSD. Another 5-7% taller gearing will not hurt. If you're boosting, any extra torque is just going to be wheelspin in the lower gears, even with an LSD.

Edit: I'm running a 3.266 1st gear as well, so a fair bit taller than your proposed 1st. I think a slightly shorter 2nd and 3rd than the TSX gears would be cool, but I don't want 6th any shorter.

I removed the balance shafts with a K20A2 oil pump swap and have a 10lb flywheel (down from 24ish lbs stock K24), that's 95% of the difference between the two that you're talking about.

Small update, I never took a good look at the old 5 speed accord not only at its stock gearing but it's rather large stock tire diameter. Gearset is on the way, Wife gave the go ahead for 3.4 from Frana as well, I love my wife!!

This remind me of the moment in fast and the furious one when Brian is talking to Jessie about the new Supra build and Brian is like : "Hey man, you should be going to MIT or somethin."
Also, I would plan to get a second set of sticky tires depending on how fast you wanna go. You really don't need too sticky of a tire for the street to have fun, and going from 235's to 315's on my mustang (all seasons to max summer) really killed my gas mileage.

So I feel making a daily driver out of an insight is similar to doing the same with a Delorean, bit too risky so I bought an 03 Civic Hybrid, stock Accord 5 speed gear set , LSD and The K20A3/A2 turbo motor is going in.... won't hit crazy numbers but will be a nice 240hp sleeper and easy to build and replace is damaged. Will be done by end of year and Ill post a thread when its on the road.