A&Q about 350Z
Q:
Depending on turbo setup, GSR tranny isn't always better. For a B16 or a low compression, stock bore B18, or a high power car running tall slicks the ITR/B16 will rip you out of the hole much quicker and get that turbo spooled, but you will be somewhat limited with top speed. GSR is a good tranny for higher powered or larger displacement cars that don't need the wicked low end gearing as they will just spin more.
A:
Not trying to argue. I just wanted to state I still feel the LS is the best tranny for Forced Indunction. I know plenty of Honda engine builders feel the same way also. The LS keeps you in the turbo's power band longer due to the longer gear ratio's. The type-r tranny and Si tranny's shorter ratio's due the oppisite. You get dumped out of the turbo power band sooner, so it's back to re-spool sooner. The Type-R/Si tranny's are the best N/A tranny's not the best Forced Induction trannys. There's no turbo to spool in N/A, no turbo power band to worry about. What makes the LS so great for Forced Induction is the same reason it isn't the best for N/A. The Type-R and Si are better instead for N/A apps.
A:
Turbo spooling ideas...
Maybe Im just crazy, but why does everyone say the turbo spooling is so greatly dependant on the gearing, I figure it will spool to whatever rpm your at. - Are you saying that long gears are better becuase the turbo can "keep up" with the increase in RPM, where as it cant spool fast enough if you have a high gear, becuase of the time it takes to increase rpm is less?
I would figure, that when idling (off the start) you'd want a very short gear to get it spooled (and just give that one away), then when you drop down to the next gear, it will already be spooling fast enough for the drop into a long gear.
I think of this mostly becuase when your sitting at the start, your not going to drop the crap out of first in a fwd car, so the turbo wont keep up anyway, so just keep it as short as possible and use it to your advantage in the other 3 gears whitch could then be signifigantly longer w/o loosing anything.
So basically what Im saying, is that you wouldnt want a long first gear becuase the turbo would basically be going from a stop and trying to start there, with a larger mechanichal disadvatage.
I pose it as a question, because I dont have a turbo, yet, so I'm really just thinking about what should be happening, and If Im wrong could ya just help me out?
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Buzz1167
Jon N
A:
Ok, I didn't get much sleep,so sorry if it sounds confusing. Okay, I think the basic Idea is that witrh longer gearing, you stay in the optimal Turbo-RPM band longer. Shorter gearing means you have to shift quicker, longer gears you can go longer between shifts. Since you don't have to shift as soon, you spend a little more time in the turbo friendly rPM. Turbo's don't kick in really until a cetrain RPM, when they are spooled enough to creat more power. This is what cases "turbo lag." Basically, longer gears keep you in the turbo-friendly RPM band longer, this means you don't shift out of it as quick. The result is that you stay in the turbo-rpm band longer, so you get basically get a little longer out of your boost before shifting. Shifting puts you out of the rpm band, you need to wait till the proper engine rpm is hit to spool the turbo before making boost again. Since shorter gear ratios shift sooner, you shift out of the turbo rpm band sooner. Basically, longer gears leave you in the band a little longer. This allows you to make better use of the HP the turbo produces at full boost, since you arn't as quickly shifting out of the optimal turbo rpm band and having to let the turbo re-spool. The turbo will still have to respol when you shift, but you won't have to shift as quick with longer gears as shirter gears. Basically, longer gears like the LS are good for turbo's, shorter gears like the type-r rock for NA. The type-r, being a highly tuned NA motor, has nice short gearing. What gearing is best depends on idf you are going turbo or NA, but if you aere going turbo, you can read above and see why the longer gearing is better suited for turbo-apps. Because it keeps you in the rpm band for a longer time period, resulting in more time to use the HP created by the boost before having to shift and let the turbo-respool.
A:
Ok, I get most of what you said, but basically my entire query hinges on the statement:
"Turbo's don't kick in really until a cetrain RPM, when they are spooled enough to creat more power. This is what cases "turbo lag.""
So take that idea off of the starting line: that means at some arbitrary number, we'll say 3000rpm, the turbo starts "actually making power" That means if you have a "long" first gear, that you will be under 3000 for longer when your starting. So My thought was to make a relatively short first gear (first gear only) and just run up to like 30mph in first, then that you have motion, you can drop down to a long gear that begins at, we'll say 3200 @ 30mph, or something like that and now your where you want to be. Then you can use the entire band for the rest of the time.
So lets take that idea, and say youve got a long first gear, so your sitting at 2000rpm off the start until you get moving; then after about 4000 rpm the turbo might "kick in" (becuase of turbo lag) and since your in first gear, its probably just gonna screw up the lanuch anyway.
And another example, say youve got a short first gear, so the engine revs up much faster, youve got mechanichal advantage, so you can make the most of the "non-turbo" time and since your revving up faster, youll probably never get full turbo boost becuase youd probably be outrevving it with the engine? But even if that happens, now its time to switch gears, and the turbo is spooled so your set, and it take less time to get through a short gear than the long one, so you changing gears sooner.
Im basically saying that a boost in first gear seems kind of useless becuase you only there for a few seconds, so you might as well just ditch it and setup for the next gear.
BTW, what exactly do you consider long and short gears anyway? I dont know ratios, I was thinking that short would probably mean 30-35mph and long more like 40-45? I know the corvette can go like 60 in first, but then again, its not turbo'd, it got it becuase its got so much friggen power it doesnt matter.
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Buzz1167
Jon N
A:
I used to have the link to a page that showed the ratio's for all the various honda trannys. The guy also had tested the longer LS tranny, a short geared jdm tranny, and one where he had swapped in different gear ratios. I forogt what he did. I know his wacked out tranny started quick, but was the slowest by the end. Not saying your idea would be, just saying however he did it, it was. He had the MPH for each tranny after each gear, including his hybrid. I wish I still had the link so you could take a look, it might help you out if you are looking as creating a tranny with custom ratio's. I the ratio's I think in first are virtaually the same in most or all of the trannys, it's the final drive ratio that is longer geared in the LS, and maybe like 2 of the higher gears. I know it's the final drive ratio that makes the diff in the LS. I've hear of ppl just swappin in the LS final drive gear into, say, a GSR tranny, to get the longer gearing. I don't know how that worked out though.
A:
Ok, so your saying that the first gear doesnt really matter too much, and thus doesnt apply to the "long gear" rule. Ok, I can get that. The first gear was the only one I was arguing about, I didnt think all the gears should be short, like an entirely new gear box, just the first.
And the tranny hybrid description is kind of the opposite of what I thought it should be, I guess its kinda the same idea. - You say people use a gsr tranny and a ls final gear, By my reasoning they should be using an ls tranny with a Gsr first gear. Is the gsr tranny better by something other than its gear ratios and thats why they use it, or maybe you can't reverse it?
I ask becuase I have a "crv" tranny, and I think its more like the ls tranny.
Buzz1167
Jon N
A:
The times I know of putting the LS final drive in a GSR tranny was when someone already had a GSR tranny. I don't think there's any advantage to doing it that way.
A:
I'LL START OFF WITH A QUESTION...WHEN DOES AN ENGINE FLOW MORE AIR? IN HIGHER RPMS OF COURSE! AN LS TRANNY TAKES LONGER TO GET TO HIGH RPMS SO THEREFORE BOOST WOULD NOT KICK IN AS FAST...A GSR OR TYPE R TRANNY STAYS IN THE HIGHER RPMS LONGER (THEREFORE MORE AIR FLOW) THROUGH EVERY GEAR SO THEREFORE BOOST WOULD KICK IN FASTER! DUH
IN TERMS OF COMPRESSION RATIO ITS BETTER TO HAVE A HIGHER COMPRESSION RATIO AND LESS BOOST THEN A LOW COMPRESSION RATIO AND MORE BOOST BECAUSE HIGHER COMPRESSION AND SMALL TURBO ACCOMPANYING THE LOW BOOST = HIGHLY RESPONSIVE & LESS TURBO LAG
THERFORE I WOULD GO WITH EITHER THE GSR OR TYPE R
A:
OK buddy are you ready to be schooled?
Yes, higher RPM flows more air. However, there is this little problem called traction. Getting to that higher RPM faster will only make you spin your tires more resulting in lower ET's. Secondly, the LS tranny is not so high that it drops your engine RPM's down that low to the point where you don't make boost when you shift. You will still be in full boost in anything over 4K RPM, so if you shift at 7K, it will only drop to like 5K so you are still going to boost in full.
I will give an extreme example for you're theary about low/high compression VS low/High boost. A 8.5:1 compression engine can boost about 18 PSI on pump gas. A 10:1 can only boost about 8. Now that extra 1.5:1 compression is going to give your engine about 20 more HP. But the 10 extra PSI of boost is going to give your engine 100 HP extra. Which do you think is going to win a race? Sure before the turbo spools the higher compression is going to jump ahead, but after about a half a second of glory it's going to be shattered at the 10 car lengths the high boosted car is going to win by.
Are you done giving your unexperienced opinion now?
A:
Well, I hate to jump on the band wagon, but they don't state that they're using a stock gsr block, it says stock b18 block with a gsr head. Also note that a 3mm(stock is .75mm) head gasket is going to lower the compression quite a bit, which would allow for more boost than a stock gsr.
If you don't have a bunch of cash laying around, I think it'd be easier to boost an LS, than a GSR or ITR. You can always swap a vtec head on there later if you want to.
However, the whole bottom end on a GSR/ITR is a lot stronger than an LS. For instance, stronger rods, wider rod journals, better rod/stroke ratio, higher pressure oil pump, water system type oil cooler, and a block girdle. So this would likely be more reliable, just more limited on how much boost you can use on pump gas before detonation.
If you had a lot of cash and wanted to go all out, there's no doubt the gsr/itr block is better, you can sleeve it to 84mm+, add a deck plate (or just buy a taller after market block), and buy all strong aftermarket internals to make it bulletproof. They you could probably put a huge turbo on it and boost it to like 20+ pounds with all kinds of crazy tuning equipment.
I personally wouldn't want to go this route, I bet you'd get like 10 miles to the gallon with all the fuel it'd take to keep you from detonating.
Really this is all speculation as I don't know much about turbos and I just like to ramble on as if I have a clue what I'm talking about.
A:
The type-r isn't made for boost you'll blow it up. the gsr c/r too high plus you have to tune around vtec. B18B is the best, you can run super high boost and tuning is way easier.
A:
y is the h22 a bad engine to turbo?
A:
What i heard is that they have a weak block for boost. Also hear that turboing any VTEC motor isnt good for some reason. But i havent heard any real explanations why. All i kno is that B-series motors have a bullet proof block for any crazy ideas. Lets see what the real JDM people say. Im like most people where im still learning a lot about JDM motors and stuff. This is an interesting thread.
Hey what about F22 motors??? Does everything that goes to H22s apply to F22s since it is the same series
A:
hey everyone, man the thread has really change. here are some dynos so we can end this once and for all. man, wish someone pm me earlier, but oh well. what im going to show u are two dynos, a turbo gsr and ls which both having very similar hp but the gsr is at its optimum psi unlike the ls.
as u can see this make 234whp at 8psi, but if u look carefully at the tq, this is only at 170. not only that, but it has a better turbo kit.
here's the ls:
with this one its making 230whp at 10 but can still go higher to 12 to reach its optimum psi. the tq unlike the b18c1 is at 207, thats a difference of 37lbs of tq! the kit in use is a drag which doesn't compare to the rev hard. at 12 psi, i infer the hp could go to +240 and +215 for tq. just like the other guys said earlier, tq will run the streets. in this long debated case of what engine is better hopefully u now know.
so to answer the guy's question and many others, the best engine for forced induction is the b18b, all hail
. i got the 92 ls b18a which make similar power results to the b18b so there wouldn't be much of a difference at all.