no, I mean if go WOT and look at the boost gauge - which is usually easiest to do when in 6th gear to slow down the accelleration to the point that you can actually read the gauge

My car idles at around 1350 rpms and I actually don't know the exact boost # I'm making at that rpm, but I am making about 1.5 psi at 2000 rpms

 

oh btw for anyone curious, here's my boost graph overlayed with ZZtop's with his exhaust and tune

I just dotted mine in since I haven't scanned mine in yet (I can if it's really necessary though)

I do make about 1.5 psi at 2000 rpms though according to my boost gauge
again, this is my car running at 10psi when it should be running 12 but the belt was slipping

ignore the sloppy parts - hp and tq was on the same chart so i erased them

 

i don't have lag inbetween shifts.. if i shift at 9 psi .. by the time i get into the next gear.. i am already 3 PSI.. i know this because if i get off the gas my car lurches forward.. and it usually only does that between 2 - 4 PSI

 

my kit comes with the biggest turbo's in any stock TT kit for the Z.. and i am hitting full boost at 3200 rpms.. so i am not sure where this huge turbo bigger lag thing is coming from..

you must be thinking about older turbo's like the T-78's and T-88's that supra's use to have.. those things use to hit full boost at 5500 rpms.. now they have hybrid turbo's that make 1000 whp and are making full boost way earlier than before

 

I think it's less of an issue at mid/high rpms. And when you're going WOT the turbo was fully spooled just moments before

in a turn though where you're half throttling at 4-5k rpms then quickly roll your foot back into WOT as you come into the straight, the turbo wasn't fully spooled and has to respool itself back up.

I don't think it'd be a huge deal, but it's probably noticeable when you're balancing the car on the knife edge of traction during a turn

 

no there's bigger turbos out there than the stock greddy turbos. Some people swap them into their TT install. There's threads about people asking about them or maybe even doing it

even the SFR kit comes with bigger turbos as standard in their kit btw

 

i wouldn't call the SFR kit a standard stock kit.. apart from them.. which other FI Kit for the Z has bigger turbo's than greddy?

 

right

I thought we were just talking about huge power, not which standard kits have the biggest turbos

the point anyway for example, the bigger JWT BB700 turbos compared to the standard JWT BB530 turbos - there's a little more lag and slightly later spool with the bigger turbos and they're of the same techology. That's just how it is. Honda and Porsche are working on dual-vane designs or something which is kinda like two turbos in one, but those are for the next era of turbos

that was all I really meant.

Bigger turbos have more lag and later spool than smaller turbos. The newer ball bearing designs do help though - no denying that

 

As shown in wikipedia here is the definition in keypoints.

What they say about your "definition"

 

I'm sure we all have Corky Bell's BOOST book...can look it up in there too. I have no doubt he got the definition right as well

the term isn't a big deal or anything, it doesn't change how these cars drive with different FI, but so many people get it wrong when they talk. I've refered to "lag" the wrong way in other threads too because the definition wasn't called into question just to make my point (otherwise only a few people would understand since they don't understand the correct meanings)

 

Yes you do, think about down shifting around a corner. everyone turbo has lag, between shifts it might be smaller then others but it is there and larger then a SC.

 

If I had the money, I would have done the same thing. Just for the APS setup w/built motor your talking $15k-20k, big bucks. What about the rest of you car, suspention, braking, wheels, drivetrain ect. When you Do engine mods like that you have to build the rest of the car for balance. GOOD LUCK.
Your car is going to be wicked fast!!!!

 

agreed, the APS TT kit rocks

I even had a downpayment on one at dynocomp at one point before I changed my mind and got a refund


one thing I don't like about the APS route though - and has nothing to do with the quality of the kit - which is TOP NOTCH, is if you need a part from APS, you'll have to wait like 3-6 weeks depending on what it is. One guy blew his engine and APS turbos with a missed shift and it was a loooong wait to get replacement parts by boat from austrailia.

Their turbos are not really repairable BTW. APS has some sorta custom design that only their shop has replacement parts for. They're not a standardized turbo like what the JWT or greddy's have. Dynocomp was saying if the kit used standarized turbos they could have done the repair work themselves and it would have all been done fairly fast

There's been at least another member on the forums who was trying to get replacement parts and was having trouble doing it without paying up the nose.

 

This has to be in a higher gear [ 4,5 6 ] and coasting , then stomping on the gas . Your 3.9 rear and 1st 2nd or 3rd gear . The rpm's will go by so fast , that when you look down to see your boost gauge you've aready gained 1000rpm .

Just looked at on of my logs . This is with a T-trim blower , that produces more boost and more boost sooner . Cruising in 3rd gear [AT5] with a 3.5 rear and at 2000rpm [ -5.5 in. vac. because of cams ] going to wot takes 1500rpm . And at 3500rpm Im making 4.9psi of boost

 

exactly right Booger, I was mentioning that on the top of this page, post 161. Otherwise I can't read the boost gauge fast enough

in my case just to get the car into gear with the ATS clutch, you end up reving to like 2000-2200 rpms while letting the clutch out

you're definetly running more boost than me with the T-trim, even your exhaust is more open than mine

 

Have you figured out that power and lag are not related? when you I will reward you with a gold star!

 

Thank you for posting that...even though you seem to think you somehow proved me wrong you actually supported what I stated earlier. Lag is that split second from when I hit the gas until the boost "hits" (for my car that's full boost almost instantly)...exactly what I stated and wikipedia supported.

Nice work

EDIT: I think you're confused about what I said...boost threshold which is what you think I defined is when I hit the gas @ 1000rpms and see around a pound of boost, it's the point in which the forced air overcomes the vacuum being produced by the engine.

 

From what I know, lag is the response time it takes for a turbo to react from the instant the gas pedal is pressed to when the turbo first begins to actually push additional air into the engine, not including the extra time after that moment for the turbo to actually fully spool.

it's the time for the turbo to compress enough air to the moment right before it actually has a positive effect on engine power, not the time the turbo is spooling and actually making the additional power

it's pretty fast on modern turbos, especially at reasonable rpms and especially if you were running full boost a moment beforehand like when you shift where the turbine might already be carrying some spinning speed

 

I like turbo lag. Because when you have a big laggy turbo when it hits full boost its like getting rear ended by a train.

 

WOW! After reading all nine pages of this thread. I have to say my decision to go with the APS TT kit has been reaffirmed.


Correct me if I'm wrong but here's what I've gathered from the thread:

-turbos generate more overall power
-power generated by a turbo and "turbo lag" are in no way correlated
-Superchargers are loud
-superchargers deliver power quicker than a turbo
-lag generated by a TT kit goes undetected
-turbos are good for drag racing