Redline question

[jpuhl777]

Perhaps incredibly dumb, but I was curious what could be implemented on our SI motors to bump up the redline to 6800-7000rpm?

Is the turbo not able to handle, valve springs, engine management software, etc? Hitting 7000 would improve many things for me. Potentially hit 60mph in 2nd gear as well for those wanting.

Was just really curious.

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[ClemsonPatriot]

Perhaps incredibly dumb, but I was curious what could be implemented on our SI motors to bump up the redline to 6800-7000rpm?

Is the turbo not able to handle, valve springs, engine management software, etc? Hitting 7000 would improve many things for me. Potentially hit 60mph in 2nd gear as well for those wanting.

Was just really curious.

A tune could be used to remove it. However, I would HIGHLY advise against it! Honda are some smart engineers and set the redline and fuel cut-offs with good reason. Removing or extending these set limits is quickly treading into dangerous water...

 

[jpuhl777]

That's what I figured. But you never know. You see some Honda motors done by spoon that have outrageous rpm levels so it got me thinking. The power of the new SI is super nice, it just hits red line faster than I'm used to with Honda motors.

 

[Doc_C]

That's what I figured. But you never know. You see some Honda motors done by spoon that have outrageous rpm levels so it got me thinking. The power of the new SI is super nice, it just hits red line faster than I'm used to with Honda motors.

Spoon motors also have a perfectly balanced rotating assembly and head work to sustain such high RPMs. These are stock, mass produced motors. Designed to operate within the specs set by Honda.

 

[17siturb0]

Perhaps incredibly dumb, but I was curious what could be implemented on our SI motors to bump up the redline to 6800-7000rpm?

Is the turbo not able to handle, valve springs, engine management software, etc? Hitting 7000 would improve many things for me. Potentially hit 60mph in 2nd gear as well for those wanting.

Was just really curious.

My question is.. why would you want to raise the redline more? Car starts to lose power up top. So that will net you no extra power.

 

[jpuhl777]

It seems with VIT tuning maybe that could have been adjusted as well (was my thinking). but nevermind.

 

[17siturb0]

People that want this car to act like the previous models where all the power was up top, you'll have to spend a lot money cause you'll need a much bigger turbo. This tiny one we are stuck with has lots of low to mid range power. And to run a big turbo on this, you'll need to do a lot of work.

 

[jpuhl777]

no worries, I like the OEM setup. I was just curious what it would take to make rpm's last a bit longer. but oh well.

 

[T_A_H]

Unrelated, but I find that first gear feels really short.

 

[ClemsonPatriot]

Unrelated, but I find that first gear feels really short.

First is OK for me. Second feels too short, in my opinion; it is actually the shortest.
1st goes to 35mph, 2nd to 56mph. All other gears are around 30mph faster than the previous gear, comparing redlines.

But yeah, I feel as if I fly thru 1st and 2nd....

 

[Bryans2k]

I'm having someone build my motor and he told me that the build will Rev up to 8k safely .. part of the build is a custom valve train so that might have something to do with it

 

[360glitch]

I'm having someone build my motor and he told me that the build will Rev up to 8k safely .. part of the build is a custom valve train so that might have something to do with it

As we continue this conversation from three years ago, I would like to add if you still have the factory turbocharger you are well past it's efficiency range at 7000rpm. While extra headroom is never a bad thing, you'll need a pretty serious turbo to justify taking this engine up to 8000rpm.

 

[CAPTS]

I'm having someone build my motor and he told me that the build will Rev up to 8k safely .. part of the build is a custom valve train so that might have something to do with it

share your build, you will need alot more to be able to rev 8k safely & to fully utilize it you need some work on the head not only on the block & yes most turbos will run out of breath past 7k rpm.

 

[Bryans2k]

share your build, you will need alot more to be able to rev 8k safely & to fully utilize it you need some work on the head not only on the block & yes most turbos will run out of breath past 7k rpm.

When going over the details of the build the mechanic told me this is what was going into it , word for word
“New bottom end with new crank and oil pump
Saenz performance rods
73mm JE pistons
Boundary oil pump billet gear
Custom oil squirter
Custom valve train 8k safe
Arp head studs
Oem head gasket”

going To pair this engine with FBO and W1

 

[racerguy180]

I'm always wishing I had an extra 1500rpm, especially coming from my old EM1 and my current DC2. Not used to shifting sooooooooooooooooooooooooooooo damn early and its only gonna get worse when I rebuild my b18c for 9500rpm.

I'm just not sure the amount of valvetrain work required to bump the l15b7 rpm ceiling(not redline) is worth it rather than improving the flow you can achieve with better compressor maps, turbine sizing & cams. Is there really any difference between the other L15 head combustion chambers(shape & size), valve shrouding in the intake port, port shape(I know sizes are diff), etc???

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