Your RB20's performance?

[SeVa-S13]

I'm basically wondering what's up with my 20...It's mainly stock with an intake filter, walbro fuel pump, Nismo FPR and an open 3" downpipe. AT around 3000rpm's, I have free reign over my boost...as in I can nail the throttle and be at 10psi in just a second or so. Now when this happens it gives me a nice kick but it quickly stops pulling so hard and seems to flatten out. Luckily, Project240 has the only other RB20 in the southeastern virginia area so we get to check eachothers car's out quite a bit and his is vastly different than mine.He's able to make full boost closer to 5k but his pulls considerably harder, especially up top. The only thing different on his setup is a full 3" exhaust with his 3" downpipe. He says he hears some turbo chattering occasionally and supsects a dying turbo so that may explain the slower spool, but even so, the power difference is quite noticeable.

The only thing I can think of is my timing--at idle it will occasionally kind of "miss." Also, even with the FPR tuned perfectly when I let off the gas on the highway at about 4-5k I sometimes get a rather loud backfire, like a gunshot right beneath my ***. Could my lack of power and slight idle problem be due to poor timing?

Also, does anyone definitively know how to time an RB20? I can find plenty of threads with vague speculation and unanswered posts all day long but that does me no damn good. If I had to guess I'd connect the clamp to the loop on the ignitor (not the ground) and then shoot the light at the crank pulley with the TPS switch disconnected? Well I always hear mention of marks on the pulley and block next to it...I see no such marks. Can anyone lend a hand here? Maybe a good description of where these things are and a PROPER how-to for timing? I know I should be faster. Thanks...

[JonPowell]

The back fire leads me to believe that you have an exhaust leak and when you let off its sucking air into the exhaust tract igniting the unburnt fuel....I would check there first....

Timing marks are on the crank pulley & the lower timing cover. RB20 time with TPS unplugged.

[Sil240]

well all he has is a downpipe no exhuastthats what i got from it

[goofynick6]

Check the o2, make sure it's getting good signal all the way to pin 29 on the ecu. ALso, make sure timing is right and no boost leaks at all.

How's your fuel pressure also? Make sure it's set right.

Nick

[rbsileighty]

Check the turbo housing to see if it says 16v-10 or 16v-12. The 12's are thrust bearing and the 10's are the BB units. That could explain the lag difference between your two cars.

I've driven 20's with both turbos and the 12 hits harder, which makes it feel faster... but I'd say the 10 is faster overall. The 3" exhaust is going to make a noticeable diff if you are running the standard dp/fp setup. What exhaust system are you running? If you have less than a 3" setup... I wouldn't be surprised if yours is slower.

The 02 stuff I don't really know much about... how much a role it plays in the running of our motor (have heard it doesn't do anything past idle... and visa versa)... so I'll let someone else advise you on that one.

I'd agree with Jon on the backfire issue... as far as the missing at idle... I hear it's normal... Hybrid's and my car both do it at idle (usually after sitting a while) every now and again.

[goofynick6]

According to the stock eprom, the o2 sensor is used from 1 to about 4 volts on the stock maf and from 400-4500 rpms. I notice immediately when mine warms up and the o2 kicks in..the idle gets smoother and lower.

Nick

[rbsileighty]

Good to know... thanks for the info bud!

[SeVa-S13]

It's just an open 3" downpipe. (It terminates right under me pretty much, no cat, no muffler...just DP)I doubt I have a boost leak because my boost gauge reads a full 10-11psi at full boost.

ANd I'd love to make sure my timing's right, if only I knew how. I found the ticks on the pulley but not clear on what corresponds on the timing cover. Is it that large kinda dent thing? That's the only visible "mark" to me. And even if that's it, I'm still lost on how to properly go about timing it exactly...

Edit: Oh, and as for the turbo differences, he has a newer model (ala no RB20 stamp on his upper timing cover whereas mine has one) And his boost gauges only shows 8psi at max, but even so, he's noticeably quicker, not just boost hitting harder. =\

[goofynick6]

My car can hit 18 psi and still have a decent leak, you should test it to be sure; it's usually hard to NOT have a leak.

Timing, yes, you go by the dent on the cover, you should have someone who has experience with timing to help show you how.

Nick

[DSMs_Suck]

Heh... you can definately have a leak and still make boost, however it will KILL your performance.

I'm about over 50% sure u have an intake leak. As far as timing.... I set it by pulling the AIC then setting idle and then timing.

[[Zero-S]]

EDIT: THIS BE SEVA-S13.

So even with a leak, I can be showing 11psi at the manifold, slightly before 3000rpms?

[goofynick6]

Yes, turbos are awesome at building pressure, even with big leaks.

HOwever, with a big leak, you'll be running super rich on boost.

Nick

[BoostFab]

my rb20 hit full boost at 4k with a super-60 t3 turbo, stock cat and stock exhaust. it hit pull pretty hard when full boost, but the flow is restrictive and loosing power due to the stock exhaust; i expect this turbo to kick in sooner after i get rid of the tiny catback.

[foCk]

ANd I'd love to make sure my timing's right, if only I knew how. I found the ticks on the pulley but not clear on what corresponds on the timing cover. Is it that large kinda dent thing? That's the only visible "mark" to me. And even if that's it, I'm still lost on how to properly go about timing it exactly...

thanks to BoostsFed

[[Zero-S]]

Thanks man, but we already guessed it and set it correctly somehow. I believe now what's robbing me is my ghetto IC piping leaking because I was shorted a piece or two with my clip so I had to make do. I don't think it worked so well or there's a leak somehwere else in the system but oh well. Thanks again.