Thread: Boosted Roller Rockers

I thought T25/T28 hybrids where supposed to be the best of both worlds?

If you ever paid attention, what was your gas mileage like. My daily RR is getting 23mpg light driving (slipping clutch), with boost it should be better. Once I fix the steering rack leak I plan on light driving the VE-T and seeing what it gets. If it's still around 18mpg, good bye VE and hello RR-T.

thats not good mpg's. i used to get 27 after i put in a new cap,rotor and plugs and thats with a/t. now i get 33-5 with a 16:1 afr tune (still a/t!!)

Is this on an RR? I replaced the wires, the cap, rotor, etc. when doing the initial build about 10k miles ago. Mind you this is 100% city though, 4 miles to work and 4 miles home 25-35mph. I got 16mpg on average with not nice driving on my NA VE, as soon as I slapped the turbo on it jumped to 18mpg even though I started driving it harder. VET cams dragged it down to 16mpg again. I increased the down low timing (smaller lobes on VET cams), and it's back to around 18mpg. AFR's are around 15-16 when cruising.

What are you using as your tuning device, RT ECU or safc?

70% highway,33-35 mpg was with a stock rr in a 01 p11, 100k miles on the od.55psi on stock wheels, Asp header, straight thru muffler, safc, injen cai. stock timing and 87 gas. full interior, 1 driver. drove like a jerk (wot) 1/2 the time as well. but mostly under 2.8k rpm

ahh okay, safc, its sooo lean if i make it 5% lower the motor will sputter and stall!
my oil turns black super fast,(mobile 1 syn 10w30) im worried about that so i re-tuned it to stock.my temps were/are perfect though. idk. i have a 600 mi round trip coming up so ill let you know my mpgs from that. but i no longer have some of those mods above. will def be lower.

Cool, I definitely like to see what other people get. So far highway only is around 28-29 for me. Still too low on VE. I've heard of people getting 38 on non aerodynamic b13's, but I guess the weight is the killer on the P11.

That's what people say... I dunno. Like I said above, I just wanted a T25 rebuild. I had to do the upgrade because the T25 I bought to rebuild was too far gone. My old black car (with a T25) would pretty much roast the tires from any place in the rev range. The T25/T28 is probably capable of a lot more on the top end, but it builds boost really late for a small turbo (look on the second Dyno Dynamics graph). It just wasn't what I had in mind for this car.

It's been retired from DD duty for a while. I'm actually getting ready for a total redo. I want to use the pistons, rods, and the p11 transmission on my B12, so I'm going to put the stock lowport and transmission back in it with a 2.25" downpipe and exhaust. I'll run it on low boost and it will be a pleasant, quiet, reasonably quick spare car.



I've only done the math on it a few times, but it is pretty typical. It gets mid teens around town and boosting a lot, and high 20s to low 30s on long interstate trips.

New to this site.... i'm currently in the proccess of bossting a RR motor just as soon as i get it running in my 92 sentra...just wondering if you guys had any wiring issued

Man looking at those graphs that is pretty lagy. Here is a virtual dyno graph from VE with GtiR T28. Peak torque is quite a bit lower. Though Peak torque itself is pretty low simply because it's a VE.

I have been running a RR for the past 8 years i my B14
it was boosted first with a T3 for 3years and then a GTIR T28 for 4 years allways saw 12 psi spiked to 13 at times.

the RR engines are good motors and gas milage was good too.

I never ran cams in it besides the stock ones but i did have the head port and polished several years ago.

JWT ecu .

What intake mani do u guys use so u can use tuned ecu's? I want to go obdi b13 ecu, I've been wanting to ditch this safc for a long time