But a turbo isnt always producing boost is what I was saying. Of course theyre always spinning lol

 

Ok NotNotaracist it makes sense that a turbo is spinning anytime there is air going through the exhaust manifold (so basically whenever the car is on). But let's say you have it tuned to 10psi and it doesn't fully spool until about 3k rpm, would that mean that the turbo isn't really forcing that much air into the engine and therefore not increasing the cr much until 3k and in essence the air it is pushing in before 3k is more so just helping the engine get more air with less work from the engine itself?

I know that was a bit scattered but I hope you get the Jest.

 

As soon as you get past atmosphere, it's pushing air in the cylinders.

It doesn't matter, though. With a FI build, you are adding exactly three new wear items to the system: the turbo, the wastegate, and the blowoff valve. Assuming the entire setup is installed correctly, the components will last as long as the motor. VW guys regularly put 200k+ on their complete OEM hardware without needing a rebuild. Evo guys are seeing 100-150k+. There are three parts of turbocharging an engine that will greatly reduce its life expectancy - A **** tune, a **** build, or beating on the car. **** tunes detonate and run too hot. **** builds fail in any number of ways. Beating on the car (racing it) puts added stress for prolonged time, which will cause failure, but is the price anyway pays for racing, regardless of NA, TC, SC, Nos, or even completely stock.

For the record: I bought my Civic at ~120k. Tossed a 15G on it a year later, around 130k. Removed it when the seals blew a year later, 160k on the clock, and a compression test showed absolutely zero change from before to after.

 

it is true that the n/a motor is constantly under elevated pressures. thats the only thing making me go boosted d than lsvtec in my car this year.

yes turbo's are wear items, but honestly ive driven boosted hondas for 11 years now and never had a bov or wastegate fail on me

 

MMR - Are you even paying attention or do you just not know very much about what you ask? Your last few posts go right back to what I was speaking of before - efficiency. Contrary to what has been said above, the turbo pushes air into the cylinders at all times the engine is running.

A engine is just a giant air pump. You introduce a turbo and it helps it pump easier (to put it VERY basically) and from that efficiency increases. Now obviously, when you start getting positive pressure in the intake manifold it means you have started a restriction for incoming air (typically valve timing events being a main contributor). This stuff is getting more complicated than what it needs to be. Take things at face value because starting to nit-pick is more counterproductive than it is worth.

 

What im curious about is at cruising speed, say 65mph, how much of an effect does the turbo have on manifold pressure? Since positive pressure increases cylinder pressure and as a result, engine wear. Since na engines cant turn down their compression vs a turbo, that would be a major contributor on engine longevity (not factoring component quality, tune quality, and build quality)

I understand that a turbo is always pumping, I just dont know what the effect is at light load, cruising speed scenarios.

 

Have you ever driven a turbo car? I am assuming not.

Unless the turbo is INSANELY small for your setup, you can easily stay out of boost. On most setups I can maintain at least 8-10" of vacuum while at cruising speed. Everything is controlled by your foot as to if you are in boost or vacuum. Since the turbo is helping the whole process MPG gains can usually be seen if tuned and driven right.

The only time you will have boost while part throttle driving at a constant speed is when the load on the engine increases from things like hills, wind, towing, ect... My favorite thing about the older Hondas having vacuum for cruise control is it acts as a boost limiter on its own. When you approach boost from the car slowing down from a hill the vacuum gets depleted in the cruise control reservoir. So it backs off the throttle. Sure it may build a pound or two but it regulates very well for what it is. The only time it wouldn't work the best is for some major hills or mountains I would assume (but I don't have any of these around me so I wouldn't know for sure).

 

I havent driven one but notaracist decided to go and get me all confused. I mentioned that during cruising a turbo engine may as well be a stock engine (since its under vacuum, and relatively stockish compression) compared to a high comp na engine. His post right after mine made my brain get confused

The fact that boosted engines dont always produce boost means under day to day commutes theyll last longer than high comp na engines if they arent abused.

And if tuned right are more fuel efficient.

 

The word boost is unfortunately used very loosely. I am sure we are all on the same page but what we are referring to is positive pressure. The moment an engine is running "boost" is being created - as in not natural to the normal suction from an engine (air pump).

 

Yeah boost to me is positive manifold pressure. Turbo or not, atmospheric pressure isnt boost

 

Most honda engines are already optimized very well, so getting more power from then in the NA way is difficult, and makes them a bit unreliable.

However, adding a turbo will add more components that could go wrong,
and stress the fuel system more.

You can minimize the problems with the following:
-a decent tune, of course
-also, decent building with decent tools
-maintenance
-proper sensors, with 0.5-4.5V output instead of 0-5V (short/open circuit protection)
-safety options in the EMS, like max temp, max boost, min fuel pressure (so the engine will not go lean in case of a clogged fuel filter, or hard cornering with almost empty fuel tank)
-a good oil pump (maybe ported)
-high quality parts. Forged internals, quality bearings, studs, gaskets, etc, will help a bit
-no crappy parts, even on "not important" places, I've seen an engine killed, because a small metal disc, departed from a crappy air filter
-water cooled turbo

Even famous builders overlook the importance of the "engine safety" tab in the EMS:

"The mis-hap on the dynojet was a bad combination of events all at once. It involved a blown fuse on one of the fuel pumps, dynojet pressure sensor being T'd into the vac line to the FPR without zipties and blowing off and a resulting super lean AFR with boost skyrocketing to 40psi and 10K rpm, and having the exhaust valves contact the pistons all at once."

 

This thread is getting better every post.

 

OK so first let me say I appreciate the input and help from everyone but if I knew about what I was asking I probably wouldn't be asking, just saying. I understand the basic idea of a turbo but there's quite a bit I don't know and yes I have been paying attention that's why I'm asking questions based on people's responses to this post. Before you ask I've driven plenty of turboed cars before but never owned any or worked on any aside from things that aren't turbo related.

Seeing as I would not only be looking around to buy or piece together a turbo kit but I would also be doing as much of the work myself as possible I want to know as much as I can so I don't want to just take things at face value. The reason's my questions are pertaining to efficiency is because I'm not just interested in going fast I'm interested in overall efficiency. Yes I'd like to go faster but I don't want a drop in mpg nor do I want a blown engine. Now thanks to people's responses and what I've researched I'm 100% sure neither one of those things are going to happen as long as things are done right.

 

Small turbo, small whp goal and you will get what you're asking for. (Mpg reliablilty)

Big turbo big whp goal then you won't get what you want.

Have you looked at the fi stickies at the top of the forum?

 

This is crazy..

And to think I drove around for a couple years without even a wideband on chrome and a stock block gsr and for some miracle my motor stood together.


Op you don't need to go above and beyond like this. K.I.S.S.

 

This has been my thoughts for quite some time. I know guys that could lets say, "break an anvil with a rubber hammer in a sandbox" with the way they drive.

 

Turbohatch96y7- I did take a look at the stickies it's just that I was hearing and seeing a lot of back and forth about reliability and fuel economy and was looking for some experienced input. I'm definitely going with a small turbo I'm just not sure which one would be good for the kind of setup I want. I'm still in the process of researching.

 

Get tghe cheapest one you could find if you're looking for MPG.

14b or t28 or 16g would work for you just fine.

 

I have a stripped 15G laying around that I'm not going to be using, just sayin'

 

dont go too small. you dont really want it spooling up a lot at like 2500 rpm. going up a big hill you would see a few psi and there goes your good fuel economy.

under moderate acceleration, something that gets a psi or so around 3000 and has full boost in the upper 3000 to around 4000 rpm is good if u ask me. it truly makes for the best of both worlds

 

And you really dont need boost below 3000rpm. Most cam shaft profiles dont start making power till around 3500-4000+rpm so it doesnt make much sense to me, to try and make boost before the cams start getting into their efficiency range.

 

Notaracist- What do u mean by stripped? What could I expect out of a 15g around 14psi? What would be safe/unsafe psi levels?

I've seen some pretty positive things about t03/4, t25, and k04. Any thoughts on those?

 

By "stripped", I mean the oil seals blew, I took it apart for a rebuild, and during reassembly the worn out shaft snapped at 6ft/lbs. It could be shipped off to a reputable turbo rebuilder and reassembled for ~$200. A 15G is a fun little turbo for a 1.6L motor that makes power in the right places. It's not a dyno queen, or a drag strip monster, but for daily driving, I personally think it's an almost-perfect turbo. It's just too small for the motor I'm building, so I'm getting rid of it instead of having it professionally rebuilt. 14PSI will be on the top of it's effective range, and it'll just blow hot air past that point, but it'll be good for a nice kick in the pants.

For a B16, I wouldn't go any smaller than a T28. T3/04e is a very "staple crop" turbo that a LOT of people use, and you can't really go wrong with it. Same deal with a GT28RS (AKA Disco Potato). I don't know much about Audi turbos, but some brief browsing through H-T and Google says the K04 is **** for a B16.

 

I have a d16z6 not a b16. I was just using that as an example.

I'm thinking if 14psi is going to be pushing it's capabilities I might want to look into something else. The t3/4 seems pretty basic and reliable for more than what I'm looking for and there everywhere. If I went with a t3/4 is there any specific one I should get/place I should get it from?

 

And if anyone has any suggestions on any shops around the San Fernando Valley that do everything it would be greatly appreciated. Yes I did look at the stickies but I didn't see anything too close by and I didn't see church, is there a reason for that?