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newaccorddriver
08-22-2006, 06:00 PM
i was wondering if its possible to use one of those and control it so theres absolutely no boost or very little boost under certain RPMs and raise it as your RPMs go up. i want something like 4PSI or so to get me started to about 4k, then between 5-6k is 10PSI and 6k to reline is 15PSI. i want it like that to retain my fuel economy during normal cruising and such. is this idea feasible with the turbo XS 3 stage boost controller and RPM switches? ill probably need my wastegate to me set pretty low, but im sure its possible even with a stock wastegate

A20A1
08-25-2006, 05:22 PM
I think maybe using two wastegates maybe?

Get a good flowing manifold though so when you open the wastegate exhaust can get out without much restriction so it'll be more like you're running N/A with a 4-1 header while you're limiting boost.

Usually though you want to turbo since it increases you VE... which gives you better performance and milage.

Just try not to get too rich as a means for controling detonation.


Does the turbo even boost at that low an RPM?
like if it's 3psi under 4000 rpm then might as well keep things how they are.

AccordEpicenter
09-01-2006, 04:40 PM
meh, you cant lower your boost pressure past what the wastegate spring is at, so if the wastegate opens at 7psi the boost controller can only raise it from there, not lower it below 7psi. Unless you get a really tiny turbo you wont be in boost unless youre cruising at a high rpm, on my car just cruising at 55mph i dont boost at all so the car should have very good fuel economy if youre not using heavy throttle all the time (somtimes better than stock if its tuned very well) and an rpm dependant boost level would be pointless because the engine makes most of its power between 4500-6k but i got full boost by 4k but before that say, 3000 i could only get about 3-5psi. I had larger turbine housing but it really didnt make it laggy 4k rpm plus and it had a much bigger top end

newaccorddriver
09-01-2006, 06:49 PM
what turbo are you running accordepicenter? i need a turbo with your kind of description

bobafett
09-03-2006, 12:54 PM
he 'was' running a .60/.63 t3. i think he was planning on running a .60/.63 t3/t4 though, i am not sure which he is describing.

if you get a tial wastegate you can order it with any spring you want. i ordered a 3.65psi spring for my initial tune. usually u can safely double the rating of a spring, so i should be able to run almost 8psi with that spring. i didnt want a 12psi spring for my initial tune, i want to take it really slow. but once I have everything all figured out, i will use something between 8-12 psi for my wastegate spring.

as for rpm dependent boost controllers, i think unless you want to spend an ASSLOAD on fancy electronics, your best way of tackling this is teaching your right foot.

most turbo cars (even with lame turbos like the k03) don't boost unless you are in the throttle pretty well.

newaccorddriver
09-03-2006, 02:22 PM
if you get a tial wastegate you can order it with any spring you want. i ordered a 3.65psi spring for my initial tune. usually u can safely double the rating of a spring, so i should be able to run almost 8psi with that spring. i didnt want a 12psi spring for my initial tune, i want to take it really slow. but once I have everything all figured out, i will use something between 8-12 psi for my wastegate spring.

as for rpm dependent boost controllers, i think unless you want to spend an ASSLOAD on fancy electronics, your best way of tackling this is teaching your right foot.

most turbo cars (even with lame turbos like the k03) don't boost unless you are in the throttle pretty well.


i thought with a boost controller, you can raise the boost level to whatever your boost controller is limited to?

for RPM dependent boost controllers, i think the 3 stage boost controller with RPM pills should be cheap enough, well, i guess the boost controller itself is $250, but its nothing like a greddy unit though(cost wise)

if the RPMs are high enough, wont the turbo be boosting anyways? i havent driven the accord in over a year, but id imagine the RPM on the highway would be about 3500RPM, so wouldnt it be boosting a small trim turbo then?

MessyHonda
09-03-2006, 02:33 PM
well if you have a 5 speed the in 5th gear at 3000RPM you are going 70-75mph and if you do 3500rpm you are going like 85-90...at 4k you are going 100mph

newaccorddriver
09-03-2006, 02:47 PM
well if you have a 5 speed the in 5th gear at 3000RPM you are going 70-75mph and if you do 3500rpm you are going like 85-90...at 4k you are going 100mph


ya, but if im going at 3000rpm and the turbo spools by 3000 rpm, then ill be boosting when all i really want is to cruise with no boost. that would mean wasted fuel economy.

how is it that factory turbo cars like the Vw 1.8T or the STI or something similar get decent gas milage even with the turbo?

bobafett
09-03-2006, 08:15 PM
its all relative guys. if you have ever driven even an NA car with a vaccum gauge, you can tell when you might be boosting a little bit, and when you wouldnt be. if you are truely just cruising on the freeway you won't be boosting.

its not like if your car is at 4000 rpm you have X amounts of boost. if you car is at 4000 rpm and you have been WOT for the last 2000 rpm then its probably going to be consistant, but if you let off the throttle, even at 5000 rpm you are not going to be boosting anymore. if you just crack the throttle plate enough to keep a constant speed you are usually still pulling a few inches of vaccum.

honestly if rpm vs boost was a problem, don't you think there would be products out that address exactly that?

its like i said in my last post. if you dont want boost at 4000 rpm while cruising, then keep your foot mostly out of the gas pedal and you won't get it.

A20A1
09-03-2006, 08:31 PM
why would it be wasted fuel economy? How you set up your fuel and ignition management would be your downfall in economy, not boosting.



Like I said before turbocharging increaes the VE... good VE is one goal every engine designer looks for.

You're turning spent gasses into mechanical energy to force in more air...
air that would otherwise have to be sucked into the engine, this would require longer durations to get more air in but then low rpm performance would suffer, thats something everyday cars want to avoid.

Don't think of is intirely as more fuel and air = more gas used and poor gas milage,

think of it as, more efficient engine = better gas milage.

Again though that falls on engine management.

bobafett
09-03-2006, 09:11 PM
i might add that most multiple stage boost controllers I have read about are meant as a form of traction control. IE in first gear limit boost to 8psi, in 2nd gear limit it to 12psi, and for everything else the normal boost limit of 15psi for example.

the reason you have the other boost limits in effect is for traction, not economy. :D

newaccorddriver
09-03-2006, 10:13 PM
if just keeping my foot off the gas and cruising really doesnt cause me to boost, then ill probably skip the multiple stage boost controller and stick with a regular one. that would probably stay true until i decide to hit the tracks, then traction might be an issue. would wider tires help me out with traction alot, or should i just buy a set of slicks for the track?

bobafett
09-04-2006, 08:02 AM
good idea on just using a normal boost controller. as for the tires you run, it depends on how much money you have to burn. personally, i will be so broke by the time i get boosted, that I know i will just be running street tires until my turbo setup has been done for a while and i can afford a pair of slicks.

assume that if you have a decent turbo setup, and crappy street tires, 1st and 2nd gear will do nothing but burn (check out accord epicenter's videos)

slicks are great if you have the money, but also keep in mind, slicks is a great way to break axles and trannies. tire spin is MUCH easier on your entires car! (except maybe the tires)

AccordEpicenter
09-04-2006, 09:14 AM
yeah if you have a 2 stage MBC its way cheaper and less of a headache than most EBC's, then you could limit your boost for say, 1st or 2nd gear until you hook up. How much youre into boost depends on engine rpm, engine load and throttle angle. I could be cruising at 6k and have no boost whatsoever at part throttle and a light load. Also if you tune with a wideband you can lean out your part throttle (vaccuum, no boost) fuel tables if you disable closed loop on say, an obd1 honda ecu so the oxygen sensor does absolutely nothing. The benefit of this is that you can actually get better than stock gas milage if you are easy on the car

newaccorddriver
09-04-2006, 09:26 AM
i never knew the turbo doesnt spool on low to no load. ill keep that in mind. ill probably stick with megasquirt for my engine management as opposed to SAFC mainly for the fact that i like home brew stuff, and megasquirt offers alot more control over fueling needs. i also have the option to upgrade to MS2 anytime i want and get EDIS for it.

the thing with MS2 is that i have launch control as an option. if i were to launch at any given RPM, would my tires be more likely to break traction as i spool up?

AccordEpicenter
09-04-2006, 07:19 PM
yeah, megasquirt offers much better control than the safc, so if you can get it to work youll be ahead of the game. If youre gonna be on slicks, esp with a lightweight flywheel, launch it bouncing off the rev limiter (seriously). On the street or on street tires is where launch controls really really help

newaccorddriver
09-04-2006, 07:32 PM
i cant get a light weight flywheel cause i wasnt in on the group buy, and they wont make a single one on its own, i cant organize a group buy as i dont think many people will buy. i think my best option is to put it on a brake lathe and grind some of the back off, then get it balanced.

thanks for the tip on the launching though, didnt know slicks offered that much more traction and the ability to redline launch