As I progress through my engine build, I've been considering the cost/benefit of revving to 9000 on my soon-to-be built b16 (CP pistons, eagle rods, stock sleeves @81.5mm). Stock, I made 252whp/174wtq on 7.5psi, and the torque was still flat at redline (8000). From the dyno charts I've seen on here, I can pick up another approx. 50whp by revving to 9.

I've heard all kinds of opinions on increasing the redline, but I'd like to discuss facts.

I understand that increasing the RPMs linearly increases the forces placed on an engine exponentially. What I'm interested in learning, is how does this apply to FI? In (well designed) NA applications, the exhaust stroke sees little backpressure due to scavenging, etc. Because of this, the tensile loads placed on the rods/pistons/etc. at TDC on the exhaust stroke are the most damaging to the engine. In FI, we've got plenty of backpressure, especially at high RPM. How much does this change things?

Also, I'd like to discuss my options for valvesprings and retainers. Most aftermarket retainers are titanium, and it seems the consensus is that these wear rather quickly. Is this related to cam aggressiveness? My car will be daily-driven and needs to be reliable. Since I'm sticking with GSR cams, is it a viable option to keep the stock retainers or use some cromoly ones instead of titanium?

I've got more to post but I think I've established a good starting point. Thanks for listening...

 

what turbo do you have? if your turbo is small at 9k it will blow hot air. just something to think about.

 

whatever the type of induction is the high engine speed will kill a rod/rod bolt in no time if the rod isn't stout and the rod bolts aren't of good quality and installed correctly. the type of turbo should drive what engine speed you rev to. if the turbo isn't getting the flow it needs up to 8k rpm to be efficient, then raising redline is ok. if you're outflowing the turbo because of increased engine speed, you're doing more harm than good (heat and high internal forces).

nothing wrong with Ti valve retainers, if you dont want to have to worry about it just go w/steel. a good dual valve spring will do its job and keep valves from floating. a lot of people are using Supertech (i think thats the name) or Skunk2.

 

supertec is what I'm using. for 525$ you can't beat it. thats dual springs and titanium retainers!

 

i no you wanna talk about how to do it safe maybe people would chime in with suggestions if you tell them you setup and get details on the turbo and bottom end and such seems like you got the facts

 

Ok, sorry for not specifiying the setup.

DC2
Spoolin Log Mani
t3/t04e 57/63
2.5" dp closed loop dump
3" exhaust
CP 9:1 pistons
EAGLE rods
81.5mm otherwise stock JDM b16 (comes w/ GSR cams).

IMO, this turbo will really be in it's sweet spot from 7k-9k rpms. Full boost hits around 6k, but it spools best at 7. That's my main motivation for revving higher, I'd like to get quick spool and not run out of RPMS so fast.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ctr83 &raquo;</TD></TR><TR><TD CLASS="quote">supertec is what I'm using. for 525$ you can't beat it. thats dual springs and titanium retainers!</TD></TR></TABLE>

I was quoted $290 shipped for brand new supertech springs/retainers.

 

with that turbo and manifold depending on what intake manifold you are running... you may or may not run out of steam up top... i ran pretty much the same set up on a stock gsr and on 15 lbs made 351 whp... revving to 8500. the supertechs will work fine.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by cobra2326 &raquo;</TD></TR><TR><TD CLASS="quote">

I was quoted $290 shipped for brand new supertech springs/retainers.</TD></TR></TABLE>
i forgot that was for valves too. my bad

 

Found some interesting info over at endyn on piston speeds:

B16A
77.4 mm 8000 RPM 20.6 meters/sec
8500 RPM 21.9 m/s
9000 RPM 23.2 m/s
9500 RPM 24.5 m/s
10000 RPM 25.8 m/s
B17A
81.4 mm 8000 RPM 21.7 m/s
8500 RPM 23.1 m/s
9000 RPM 24.4 m/s
9500 RPM 25.8 m/s
B18C
87.2 mm 8000 RPM 23.3 m/s
8500 RPM 24.7 m/s
9000 RPM 26.2 m/s
9500 RPM 27.6 m/s
B18A/B18B/B20B
89.0 mm 7500 RPM 22.3 m/s
8000 RPM 23.7 m/s
8500 RPM 25.2 m/s
9000 RPM 26.7 m/s
9500 RPM 28.2 m/s
B20A
95.0 mm 7000 RPM 22.2 m/s
7500 RPM 23.8 m/s
8000 RPM 25.3 m/s
8500 RPM 26.9 m/s
9000 RPM 28.5 m/s

Looks like more ammo for the high-revving argument. B16A @ 9000rpms still has less piston velocity than a B18C @ 8000.

Also, Jeff Evans recommended that I look into stock retainers and skunk2 tuner series valvesprings. Sounds like a good fit for my setup. Here are the specs:

# Seat Pressure: 50lbs@1.320"
# Open Pressue: 210lbs@0.800"
# Bind: 0.800"

Acura USDM 98-01/JDM 96-01 ITR Valve Springs
Variable or Linear: Linear
Seat Pressure: 50lbs
Max Lift: 11.5mm
Coil Bind: 11.7mm
Pressure @ 11.5mm/.453" lift: 150lbs

So, same as stock seat pressure, higher open pressure. Good to 9000?

 

raise the boost before running more rpm's. i went to the dyno yesterday same setup but with only 2.5" DP made same power on 7psi but a little less tq.

earl rpm stands for something but i cant remember right now.

btw, how are you spooling at 6k ? i get full boost at 5400.

 

For me, spool time depends on when I floor it. If I floor it @ 5000, it takes longer to hit full boost. It spools almost instantly at or above 6 though. If I floor it at around 3500, full boost will hit by 4500, depending on the gear.

 

all of mine were 3rd gear pulls. forth gear will probably net a little faster spool up.