KevinK2

This is not to argue the many +/- 's of non-sequential over sequential. But the rpm where full boost occurs depends a lot on how it happens, and what full boost is. If the engine is already loaded, and the test starts at 2300 rpm in 5th, uphill, and full boost is 10 psi, it will hit that a much lower rpm than the same car set for 15 psi full boost, starting with a deceleration and nailing it a 3000 rpm in 3rd, down hill.

What is needed is a standard, easy test to compare NS set-ups, to see/confirm what works best for minimal response time. I set one up at one time to compare different turbo set-ups, and it worked well.

Open to suggestions, but would start with a 3rd gear test on flat road, no wind:

1) light cruise a while to pre cool IC, intake.
2) stabilize speed at 2500 rpm.
3) foot off pedal for 2 seconds (make sure no variable initial engine load)
4) floor it and either check time to 10 psi, or rpms at 10 psi.

This assumes most have boost set above 10 psi, or initially will spike to 10 psi. Most gages have a big tic mark at 10 psi for easy read.

Report results and mods. Could help expose some set-up problems if same mods show much different response.

Normal good mods would include full NS conversion, DP, HFC or mid pipe, 3" exh, SMIC, no clipping turbine, 99 spec turbos, and PFC with best timing map.

Lets FIRST agree on a final test method and get some numbers.

It's not perfect, but better than claims that are not really comparable.

jimlab

When I talk about "full boost by ~3,200 rpm", I'm referring to a standing start, in 1st gear, and "full boost" was 14+ psi (measured with a GReddy 60mm peak hold gauge). I never bothered to check in any other scenario, because a downshift to 2nd from 3rd (for example) would peg the boost gauge almost immediately.

Configuration:
M2 reprogrammed ECU
Crane HI-6 ignition
SX rising rate FPR
Cosmo 20B fuel pump
Stock injectors
No A/C
No power steering
No air pump
GReddy underdrive pulley kit
Custom cold-air intake
ASP large IC with GReddy elbow
Tri-Point stainless downpipe
Tri-Point stainles midpipe with Borla XR-1
PFS cat-back, then RB twin tip cat-back
Full non-sequential, wastegate ported, exhaust manifold ported
Manual boost controller (primary turbo to wastegate actuator, bleed valve from WG actuator)

One problem with comparison is that I doubt most people would go to the trouble of converting their cars and stick with stock boost levels, so you'll have to specify what "full boost" consists of for each case.

Personally, I think a lot (if not all) of the reports of lag can be attributed to configuration (i.e. still have one cat, did "poor man's" conversion, etc.) or driving habits (people not downshifting at low rpm and expecting boost to pick up immediately).

BigIslandSevens

iTrader: (4)

<<I never bothered to check in any other scenario, because a downshift to 2nd from 3rd (for example) would peg the boost gauge almost immediately.>>


Exactly, It is absolutely amazing to me how LAZY most people are. Is it really THAT hard to downshift? NO . But if one feels the need to be a lazy driver and not downshift, pretending they have the same response as if they were to downshift,( due to the primary turbo spooling).. well to each there own.

A downshift onto the secondary turbo will be way better than lazy-manning it from the primary a gear to high. Just my opinion. BUT non- sequential is the best driveabilty mod one can do to these cars. Next is a LS1, or other monstrosity

mark57

Ditto here - boost gauge pegged to 15 psi near instantaneously. Meineke Car Care FD's E6K tuned on dyno and fine-tuned on street and track w/ WBO2 as well. The car is outstandingly quick because the conversion is correct and thorough......

KevinK2

Big Konas, start another "debate" thread, or do a search if you like to read about circular arguments. This thread is simply to converge on the best way to go NS with the least lag, for the many that value that parameter.

Jim, for the type of test described, I think the boost rise will be gradual enough so that a visual boost check would do it, no need to reset the controller. Your list shows why it worked well for you ... lots of good mods and no bads.

BigIslandSevens

iTrader: (4)

Big Konas, start another "debate" thread, or do a search if you like to read about circular arguments. This thread is simply to converge on the best way to go NS with the least lag, for the many that value that parameter.

^^ If that is directed at me you need to blow!! I agree with the nonsequential!! I didn't state one thing that was argumentative. YOU started another thread about the SAME damn topic covered 2 threads below!! Please clarify your stinky statement!!

Here is my opninion on the conversion.... I copied it so you don't have to bother yourself with actually READING it!!

BUT non- sequential is the best driveabilty mod one can do to these cars.


How is that a circular argument? You are opening a bigger door for debate than i ever could have.
Aloha

jimlab

Probably, but I think the proposed test scenario is somewhat biased towards a sequential configuration. In other words, I'd expect a non-sequential car to perform poorly following the directions you specified.

It's sort of like Car & Driver's 30-50 mph top gear acceleration test. Of course a Camaro/Firebird or Corvette with a 0.50:1 6th gear is going to fare badly (9.8 seconds for the 400 horsepower C6), so what's the point? Anyone with a brain would downshift instead of just flooring the gas pedal and waiting for significant acceleration to show up. What kind of a moron would be cruising in 6th gear at 30 mph anyway? Bottom line, you have to look at the validity of the test and whether the results are skewed by the test conditions themselves.

That said, I don't know of a "fair" way to compare the two. I know that non-sequential works fine at the drag strip, on road courses, and during 10-11 months as my daily driver, just fine on the street. I think it's driver behavior that has to be modified after the conversion, and some people expect a non-sequential car to behave just like it did when it was sequential in certain situations. I didn't have to change my driving style at all because I always downshift when I want to get somewhere in a hurry.

The point was that this thread was not intended for debate on the merits of non-sequential (or not), and your post agreeing with mine and proposing non-sequential as the best drivability mod short of a V8 is the type that would tend to spark a "debate"...

Kevin's just looking for proposals for a fair test of the two configurations for comparison, and unfortunately, I don't have one at the moment.

KevinK2

I started a thread about accurately quantifying NS response time when you are at lower rpms. I thought it would be useful, based on how a recent NS thread went. My thread was not already covered by that thread.

Stinky statement? Jim, consistent with my thread, posted his succesful mods, and commented on the proposed comparison test, and gave related opinions. Perhaps I missed it, but I saw nothing in your post related to quantifying NS response as I suggested.

KevinK2

I think I did not make it clear that this was not to test S vs NS, but to just see what NS setup works best for those that want low end response too. Looking for numbers from NS users only, numbers that would likely quantify that there are NS mod combos that give the best low end for NS guys that value it.

jimlab

Sorry, I missed that distinction the first time I read your post.