V8 T88 - S15 VH45de-T88-34d Project

[Clifton]

Pardon??

Spool time is of little importance ... i'm sure you can get a T70billion to make 5psi at 3500 rpm on a 2 litre ... WOW ... my point is ... it will be the biggest piece of CRAP until the compressor becomes efficient. Its not complicated.

The use of nitrous or higher octane fuel can increase "spool time" significantly! I mean is it that complicated? Higher oxygen content in the combustion chamber = ??

You must have compared a power curve using 98 RON fuel and say C16?? Obviously i'm assuming you are tuning the engine to make the most of both fuels.

Also explain to me why it is very common to run boost per gear or boost / rpm tables or the most common (found on electronic boost controllers) ... gate pressure??

The reason being ... controlling the boost curve controls the power curve. Increasing peak boost (or increasing the gate pressure) improves spool and peak power significantly.

yes MOST high power performance cams HURT spool time. Because they open the duration right up and increase overlap. But then they also gain another 1500 odd rpm up top in the process

Yeh good idea!

Ah, we agree on 2 things .

Spool is of importance. You said it won't do anything till 5000 rpms. Maybe you should have been clearer on what you meant by anything. I took it significant boost (10 psi+) It will make decent boost much sooner on a 4.5 if it will do it before that on a 3.0. That is important on a street car. To me 18 psi is pretty high for pump gas. I don't think anyone will disagree. I am just saying if it will be making all the boost needed on pump gas much before 5k on a 4.5l motor.

Gasoline is stoich at 14.7. Octane doesn't effect that. Some race fuels have a little more oxygen but it will not make much of a difference in the AFR if at all. Even 10% ethanol / 90% gasoline will still be stoich in the low 14's. If you comparing say methanol with a stoich of 6.4 then yes that is a different fuel and would require a complete different tune. I never mentioned nitrous and know nothing about it.

I cannot explain to you why people run boost per gear or boost / rpm tables. I don't. I do not run an EBC. The same can be accomplished with manual regulators (not bleeders). Yes you can control the boost curve with an ebc but you cannot make it come on any faster if the wastegate is fully closed.

[Ezekial]

ever put a adjustable pressure source up to your wastegate? to see what psi it "starts" to open at?

7psi spring ... will actually start to open around 2-3psi7psi spring and running 18psi courtesy of a bleeder ... and the gate might start to open at 10psi or so ...

Now run an electronic boost controller with the gate pressure set to 16psi (still peak of 18psi) ... and tell me it doesnt come on earlier and stronger

And yes ... my meaning of not doing anything is somewhat different ... i'm talking about the big KICK ... eg. my other car was making boost at 3000 rpm ... but it just didnt get going until about 5500-6000 rpm because the turbo was just too big ... mind you it revved to 10 which made it half ok

[defrag010]

I haven't heard anyone mention yet about how static compression will also have a Huge affect on spool time of a turbo.

[Clifton]

We are starting to agree more.

Yes a 7 psi srpring trying to run 18 psi. It will open early. The most I could get with a 7 psi srping was 22 psi total and the boost would fall. It will not crack at 2-3 psi though. I know my 1 bar spring opens at 18 psi off the car. I also know that turbine pressure will help open it a little sooner but that is a little harder to check. I have tested nearly everything with an adjustable source. I have a pump with the identical gauge I run in the car.

defrag.. I'll mention CR and spool. It will not make a huge effect on spool but will make some. I have dropped motors nearly a full point. Maybe 2 points would make a noticable difference though but I wouldn't say a huge difference.

[Ezekial]

I haven't heard anyone mention yet about how static compression will also have a Huge affect on spool time of a turbo.

dynamic compression yes of course. i think once vvt turns on it will aid in the spool up time of the t88. for sure

[taylon]

what car should i get im swaping engines with anyone you pick

nissan s15toyota supranissan skylinesubaru wrx imprezascion tc 2006mitsubishi lancer evo 8ACURA TSXMAZDA RX-8

[slownslurious]

ummm. what are you swapping? some of those are FWD, AWD, or RWD... some of them have pretty darn good engines stock, too.

[aaronsnocker1]

That looks terrific. Keep up the great work. I have been following your project for a while now. Great to see progress.

[David Steele]

dynamic compression yes of course. i think once vvt turns on it will aid in the spool up time of the t88. for sure

Are you saying the Cam phasing vh45 turns on and its not always active?

[Ezekial]

if it was always active then it wouldnt be "variable" would it

[David Steele]

It's always active, Just like Honda I-vtec ( has active cam gear ) and BMW double vanos which is the same thing.

I've even tuned mines in my Honda with Hondata from idle to max rpm I had it change position accordingly, I'm sure the Nissan version is no different.
Modified by David Steele at 12:06 AM 8/10/2006

[Ezekial]

you're not sure. you're assuming and your assumption is incorrect

[David Steele]

Yeah Nissan version is ''so different'' that your not explaining. it has the same style oil pressure control solenoid as my Honda does for its VTC cam.

Cam phasing is always active if it wasnt it would be a regular camgear.

[Ezekial]

switches on off on ... i believe it is basically rpm triggered from factory ...

it is not continually active. its either ON ... or OFF ... it simply changes opening and closing angles by a 20 degree increment

like other "nissan" engines with variable cam timing ... ie. SR20DET

[David Steele]

switches on off on ... i believe it is basically rpm triggered from factory ...

it is not continually active. its either ON ... or OFF ... it simply changes opening and closing angles by a 20 degree increment

like other "nissan" engines with variable cam timing ... ie. SR20DET

Honestly do you hear what your saying? Through out the 360 of rotation its switch on and set to a degree then its set off and does it shortly again based on BTDC AND ATDC thats called continuious w/e you'd like to call it intermitent.

[Stinky]

It has nothing to do with btdc and atdc. The cam gear basically rotates relative to the cam causing it to advance or retard by a set number or degrees. It's just like an automatic adjustable cam gear basically. It takes affect during certain rpm ranges regardless of engine position.

[David Steele]

It has nothing to do with btdc and atdc. The cam gear basically rotates relative to the cam causing it to advance or retard by a set number or degrees. It's just like an automatic adjustable cam gear basically. It takes affect during certain rpm ranges regardless of engine position.

Why are you explaining something we already know?

If it has nothing to do with positions which is in the subject of ATDC or BTDC where the only place its useful what the hell is the point?

NVCS works by monitoring engine rpm AND POSITION. If there was no way to tell position how the hell do you think it works?

As I was originally saying is regaurdless if the oil pressure control solenoid thats part of the NVC is switched on or off its still constantly active montoring and exactly pinpointing the times to move the cam gear

[Ezekial]

David ... there comes a time in every arguement when the person who is wrong REALISES he is wrong ... are you there yet??

[defrag010]

ohhhhhhhhh dang he dropped the bomb!!

[maxnix]

Nah, Ezekial, you don't get it. He's never wrong.

[Ezekial]

Nah, Ezekial, you don't get it. He's never wrong.

its starting to become clearer to me

[David Steele]

Right and 4 stroke engine is that slow that the cam has time to actually stops moving ! .... Not.

Take a shot at the sae paper on NVCS.

Unlike you two I've delt with a cam phasing system, knows how it works and tuned it I've made my turbo chargers spool faster by tuning it I've made better idle I made my vtec come on sooner the list goes on. I honesty dont know who your're calling wrong perhaps its some joke you made?