boost at cruising speed

[F22hybrid91]

Being as my build ( f22a1 with 4g63 pistons, h22 rods, and 14b turbo) is going into my DD. im kinda expecting full boost around 3000-3500 rpms i cruise at 3000-3300 in 5th. Would it be bad for turbo or valves or pistons to be "boosting" full psi for EXTENDED (If I wanted to roadtrip 2000 miles) time? I understand that at "cruising speed" you wouldn't have the T.Body opened up very much but regardless, 3500 rpms boosted or not boosted still pulls X cfms thus causing boost at cruising speed. If said cfms were inside turbo spool parameters. My only two solutions would be oil cooler on drain line side of turbo and 3.5 exhaust for "wasted boost", or a bigger turbo. Which I don't really want a bigger turbo. Really wanting some boost in the lower rpms where I tend to stay. (too many tickets and past the speeding and racing days. Unless I'm at the track.)

Any help appreciated

[Raf99]

I don't see any issues. Turbo is always moving, flowing, spooling under idle or cruising. No need to cool the oil more, etc. Heat soak would come from engine heat and high rpms, etc.

[oni_cb7]

I agree with Raf99. I don't see any issues either.

As long as the car is running cool, then you don't need to worry about the heat it can cause. The heat becomes a problem when you don't let the car cool down properly when you go to park it. Turbo timers exist for a reason.

[deevergote]

If you're at full boost by 3500rpm, the air coming out of the turbo could be extremely hot... which could indeed damage valves or result in detonation. I don't imagine the 14b would be at it's limit at that low RPM, however.
Many people have used that turbo with little trouble. Some even with stock F22A pistons (which is a bad idea, but some of those lasted a good long time despite that!)

[F22hybrid91]

If you're at full boost by 3500rpm, the air coming out of the turbo could be extremely hot... which could indeed damage valves or result in detonation. I don't imagine the 14b would be at it's limit at that low RPM, however.
Many people have used that turbo with little trouble. Some even with stock F22A pistons (which is a bad idea, but some of those lasted a good long time despite that!)

I'm not saying its at its limit. But id have access to full boost (8 psi on built bottom) by or before cruising rpm. Just concerned if it could be bad and any ways to prevent damage since its my DD. Larger intercooler than normal? I'm considering remote mount, but would go with t3\t4 if I went that route.

Any feedback?

[Raf99]

I'll put it this way. The 14B is used in other cars, most likely 5 speeds. I doubt their highway cruising speed is any different. Heck my 5th gear highway speed is almost 4000rpm. So ya, no worries man. As long as the engine stays within normal operating temperature.

[deevergote]

After looking into it a bit more, apparently DSMs hit full stock boost at 3000RPM or so (according to posts on DSMtuners). I suppose that means anyone on here that's used a 14b has hit full boost at cruising speed... so my fears are apparently unfounded.

As Raf99 says, as long as your engine temp doesn't go up significantly, you should be fine. Get a good intercooler, and you should be fine.

[steelbluesleepR]

it won't be an issue, since your turbo will only be at full boost under full throttle. When cruising, your engine (and therefore your turbo) has a much lower amount of air moving through it, so it won't be moving nearly as fast.

[F22hybrid91]

it won't be an issue, since your turbo will only be at full boost under full throttle. When cruising, your engine (and therefore your turbo) has a much lower amount of air moving through it, so it won't be moving nearly as fast.

Regardless of MPH. Mph is achieved by rpms of engine. Rpms of engine demand x cfm(for giggles lets say 100 cfm per 1000 rpms) 3000 rpms is 300 cfm regardless if you have it floored or cruising. Just cause your cruising with throttle body cracked open doesn't mean your cars engine isn't demanding 300 cfm at 3000 rpms. So if 300 cfm moves the turbo fast enough for full boost regardless of WOT or crusing the turbo will be spooled up. So yes the turbo is under boost at crusing speed which for me is around 65-85 mph which sets my rpms at 2800-3500 rpms. Guarantee if after I build it if I let off throttle at crusing speed the waste gate will open up and ill hear a "pssh"

[steelbluesleepR]

Regardless of MPH. Mph is achieved by rpms of engine. Rpms of engine demand x cfm(for giggles lets say 100 cfm per 1000 rpms) 3000 rpms is 300 cfm regardless if you have it floored or cruising. Just cause your cruising with throttle body cracked open doesn't mean your cars engine isn't demanding 300 cfm at 3000 rpms. So if 300 cfm moves the turbo fast enough for full boost regardless of WOT or crusing the turbo will be spooled up. So yes the turbo is under boost at crusing speed which for me is around 65-85 mph which sets my rpms at 2800-3500 rpms. Guarantee if after I build it if I let off throttle at crusing speed the waste gate will open up and ill hear a "pssh"

that's not true at all. you use WAY more fuel and air at full throttle than you do at partial throttle.

and yes, you'll here that "pssh", but it won't be full pressure.

[F22hybrid91]

that's not true at all. you use WAY more fuel and air at full throttle than you do at partial throttle.

and yes, you'll here that "pssh", but it won't be full pressure.

Your not understanding. Yes WOT will use more fuel, but the engine demands more cfm as rpms increase. Again for giggles using 100 cfm per 1000 rpms, (lets add fuel consumption figure per 1000 rpms as .01 gal just humor me.) so WOT (+.02 for WOT fuel enrichment) is applied, rpms increase peaking to roughly 6000 rpms, so 600 cfm so .06 gal +.02 fuel enrichment =.08 gal at WOT. As I'm using 14b ill get some spool by 2200 rpms and full boost around 3000 rpms. And it'll pull to 6000 rpms. Now note my turbo is at full boost at 3000 rpms, 300 cfm, .03 gal. Now pay attention here's the important part. I cruse in 5th at 2800-3500 rpms. Which means to maintain the apx 3100 rpms the engine will demand 310 cfms and .031 gal of fuel. So the turbo which is under full boost at 300 cfms should be under full boost based off the cfms required by engine. Does it make sense now?