I have a BIG jump in power at 5858 right now and the tune I'm running had the fueling set for a dual runner mani. But the burst in power is enormous (for n/a) when the runner opens. I tried leaving the runner constantly open, but low end does suffer and the car still has a smack in the *** at 5858 (prolly due to ecu tune).

What I want to do is have the runner come in about 1k rpm sooner than stock. Just wondering if anyone has done this on a modded gsr ? I have larger than stock bore and more compression... so I figure I might be able to utilize the 2ndary earlier than usual.

COmments ?

 

what cams are you running?

 

Still on the stock gsr cams. Most of the work is on the bottom end.

 

I can modify on all my programs, if you can;t find anyone and need an eprom from me PM me or email gbrtuning@aol.com

Greg

 

Thanks Cheetah, but I have a chip, I know it can be changed for the dual runner, but what I wanna know is will I be able to make power and have more power under the curve if I lower the rpm req'd to open the 2ndary ?

BTW, I really like the low end the dual runner manifold gives, which is why I haven't contemplated switching or upgrading just yet. (stock header and manifold catches ALOT of people off guard...lol)

 

in my experience changing the opening of the dual runners on stock GSR cams gives no net effect... more likely it is a timing or fuel map issue... my tuner tried it on my Hondata S100 and whenever he changes the opening of the dual runners and adjusts timing and fuel for it adequately it yields almost the same power curve as when he leaves it at stock activations (4400 VTEC and 5600 short runners, i think)... i assume it would behave the same way with a higher compression motor only the curve will be higher (HP & Torque)...

 

Well... I'm hoping the larger displacement and compression will give me a couple horses in that area. I mean the dual runner coming in is like a kick in the *** right now... not smooth like a stock setup at all.

 

you need to get it tuned...

 

Of course... saving for the dyno as we speak.

 

when my car was tuned. the higher up we moved the secondaries the more power it made strange right lol. i have a ported gsr manifold and skunk2 stage2 cams.
at one point he set the secondaries the same at vtec. later moved it all the way to 7100 picked up a good bit at the midrange top end didnt suffer at all from it.
driving around when they open up the power surge is nuts. i feel the secondaries kick in its way louder then vtec and ur head just gets thrown back.

 

With the stock cams, that's pretty much what it feels like... you get pinned in the seat somewhat. Vtec engagement at 4800 is quite tame.

 

I had a similar issue with my gsr motor. The power jump when the butterflies opened was very obvious. It got worse when I installed ctr cams. I removed the butterfly assembly completely from the manifold and had it ported. I also switched to a chipped p28 ecu and tuned it properly for fuel and timing. After the ecu was tuned my engine pulled even harder through the whole power band. The dyno will help you tons. Good luck

 

^^ good to hear, since I will prolly upgrade to ctr cams as well... damn aftermarkets are mega expensive down here. What kinda #'s did you dyno w/ those cams ?

 

My JDM GSR motor w/stock block (10.6 comp), chipped p28 ecu, VAFC, ctr cams, type r tranny, ported manifold, and I/H/E put out 178 whp and 127 tq. It took about an hour to tune the engine on the dyno. A/F ratio running at about 13.2. I don't have cam gears yet (but soon). Not bad power at all, but I still want more. What kinda numbers are you expecting?

 

I might be a lil optimistic, but I'm expecting about 170/180-ish on the gsr cams and 11.6:1 CR, purely based on past races. But with my clutch slipping the way it is...I won't be seeing the dyno for a little while longer.

 

You have 11.6 comp (did you change pistons) or do you mean 10.6 which is stock for JDM GSR?

 

I had the car in the states for a year or so... so I have a usdm engine.... and I rebuilt the block.