3rd Gear Highway Comparo: new BNR3s vs plain-bearing GT35R
 

Thought this was interesting.....ccarlisi and I just got back from playing around on the highway.

3rd gear pull at 3 honks, ~5k rpms to redline. I'll let Chris post the results, but will go over my setup:

Motor built and ported by myself, using Genghis' housings as a rough template
new BNR3s set up full non-seq running 13 psi for these pulls
M2/ASP large SMIC
All accessories deleted and running one stock main pulley
K&N filters (hardpipe kit deleted)
downpipe/res midpipe (magnaflow muffler)/PFS Catback
850cc/1300cc/Supra Pump
Jacobs FC1000 amp on FC leading coil/9 heat range spark plugs
TB coolant deleted, DT deleted, UIM opened up

My Techedge was showing full rich (AFRs in the 9s) at WOT so more tuning is definitely needed.

What a tease ;) so how much better are the new bnr's???

Bottom line: Rich won. My reaction time was worthy of a retirement home resident, but even after I got into it I couldn't match his pace. Near the top of 3rd I was even with his speed at best. It wasn't a run away, but there was little doubt in my mind that his car was faster.

Here are the relevant facts:
-I was running 14psi to his 13
-I have a substrate cat and he has a midpipe
-I don't have an ignition amp and the car was breaking up a bit at 5800+
-afr 10.7
-I still have power steering and ac pulleys.
-I have less timing split, and the same leading.

Whenever AEM sends me a working ignition amp I will install it and see if it helps. I remember when I dynoed the car with stock twins and no amp it only made 1-2hp more at 14 than 13 due to breakup, so that could explain at least some of the gap. I'm sure the cat wasn't helping either.

In any event I was very impressed by the BNRs.

Thanks for being objective Chris. I'm sure we'll be able to work out the bugs in both of our FDs over the summer :).

One thing I forgot to mention: I am currently running stock rims (vs the 17inch Fikses and S03s, which are definitely heavier than the stock setup).

Rich

Hurry up, Bryan, finish building my Stage 3s.....:D

I wonder how much the metallic cat is holding Carlisi back vs a midpipe. May I suggest a repeat run once he fixes his ignition..... :cool:

he is also running a custom 3.5" turbo back exhaust, not sure if that is much of a factor at this boost level.

Of course.... the weather here in NJ is typical humid, hot and poor air density.... so that also plays a big part.... would be curious to see this little exercise repeated on a cool to cold night.... Would be interesting

Rich, get that car tuned damnit...it sounds like you've worked out pretty much all of the issues with that car...:)

Hopefully 3 weeks from now, I will be fully up and running again with the Stage 3s setup sequentially. We'll see how see runs. I look forward to running a single turbo FD and seeing how it goes....

its not a GT35R if its plain bearing the R stands for ball bearing

I would like to know all that can be told about these. Yes i have read, but more info the better! The BNRs are what I plan on getting down the road.......

It's a 35R compressor (.70 A/R). As for the cat, it's hard to say. I installed it when the car was not tuned (so I wasn't beating on it too much) and it didn't seem to make a difference. My friend installed it on his single and it got rid of his boost creep issue at 11psi, but he didn't feel a difference in power from the seat of his pants.

Chris,
that 20B will sure help :)

Yeah, but by the time I get that project done Rich's ego will be the size of a Supra :D

Hm, by the time your project is done we will all be in hovercrafts so your analogy is lacking :D

On a serious note, this thread has nothing to do with driver skill or lack thereof. It just shows that the BNRs (a somewhat unknown quantity) can measure up to a known quantity. Case closed.

Judging by the picture, I take it that you mean you have a metallic substrate cat, correct?

Yes and no. I'm with him in the fact that AEM has screwed us. The ignition breakup he's getting I'm sure is slightly better than mine (I'm at 15 psi) and holy hell if you don't loose a lot of power from that. I think that had the setups been more level, he would have had the advantage. But I don't deny that those BNRs aren't a potent package.

Oh yeah, and I wouldn't wait for AEM to come up with something.

the 35R isn't even awake at 14psi.

Correct. I was thinking of running one but now I'm not so sure.

In my opinion AEM is a horrible company.

His breakup made the car undriveable and then he installed some of the b10egv's, made all the difference in the world. I was driving when he was tuning at 15 psi and the car pulled hard, and all the way to redline, so his FD definitely moves down the road.

True. According to Bryan my turbos are most efficient at 17-18 psi, so I think that can be said for both setups.

Rich, how many miles do you have on those BNR's now?

With a .70A/R hot side, you should have stated off at 2000rpm. That is going to hurt your top end.

I have a GT35R 1.06 and is spools much faster that stock non-seq. I say it spools almost as good as stock seq.

Not only that..of which I totally agree, but comparing these two setups right now is not much of a comparison. It doesn't matter how well they say a cat flows, it in NO WAY compares to a straight thru pipe. Then you have the ignition breakup issue....might as well turn the key off.

Rich- if you wanted a real comparison we could have played around when you were on the island. If would have been perfect- BNR's vs stock. You should shoot down one Saturday night and hang...
John

When we were tuning the intake temps were in the mid to high 30s on the pfc and I tuned the afr to 11.3-11.5 (below that the car was running rough). Last night the intake temps were closer to 50c on the pfc and the car is running at lot richer (10.7). Therefore, it appears the temp correction factor isn't doing its job. This week I hope to find some time to do some research in this area.

Of course, his car was also affected by the temp change, but I think it had a bigger impact on mine because I am not running an amp.

Are both cars using the same engine porting? Another potential delta in the comparison
Definitely an interesting if not a bit skewed comparison.
No arguing whose car is faster on the day but using this as comparison of one component vs another component when it is the entire *system* that id being compared it's hard to draw any conclusions.
I've always liked the idea of two smaller turbos for quick boost response but with enough puff for high rpms.
I'd like to see you guys do this again when issues have been worked out and operating parameters are more equitable. As noted the GT35R (not really a "true" R from what I've read though) really doesn't become efficient until the 17psi range though. So what do you want to compare? BNRs at 14psi where they are more efficient or GT35 at 17psi where it is more efficient?

Regards,
Crispy