turbo question

[NvidiaForTheWin]

hi.
as some of you know i have a 99 accent with a t28 turbo.
not fully installed , but seem like it will not hit full boost ( 10 psi ) even at redline , wich is 6k rpm ( can't shift higher , it's a f***ing automatic ).
i need to wait till the setup is completed to be sure ( only need wideband gauge and bov ) but here is the wuestion.

i worked alot with turbo like t15 t3t4 etc... but first time with t25/t28.

what is the difference between t25 and t28 ?
i know the t28 have bigger compressor so it's able to give more boost , but what about the turbine ?
i know in size they are very similar so its a direct fit with the downpipe and piping not even need to rework anything.
will the t25 give me full boost before the redline ?

my engine run strong , take no oil or anything. but the compression seem to be lowered with the time ( well... 302 000 km original... it's understandable lol )

t25 may be the only route for me , because a t15 will spool too earlier . i don't want it to hot full boost at like 2500 rpm. for street its a total shit but you already know that.

hyundai scoupe turbo have a t15 and hit full boost ( 5 psi i think ) around 3500 rpm.
but it has lower compression. mine is bone stock.
that mean if i put a t15 on mine , it will hit full boost ( 10 psi ) berore the scoupe hit its 5 psi full boost ( or whatever its stock boost ).
so t15 option = FORGET IT in my case.

no , i don't want to swap the scoupe turbo piston on mine. lower compression but weaker ( conrod too ) and anyway i don't want to put that cash on my engine as i change after the winter.

if the t25 isnt going to help , any other solution ?
NO EXPENSIVE ENGINE MODS !!!!

thanks

[darkjedi]

Do you realize that the engine cannot produce enough exhaust pressure to spool the turbo faster? mod your ecu to drop in more fuel.if theinjectors are big enough your turbo should go up to 12 psi, or so. some engines are really not moddable. I know , I have tried with some.

LE: Or perhaps you have a leak in the intake piping. If that is the case it won't make much of a difference anyway, but every bit helps.

[NvidiaForTheWin]

Do you realize that the engine cannot produce enough exhaust pressure to spool the turbo faster? mod your ecu to drop in more fuel.if theinjectors are big enough your turbo should go up to 12 psi, or so. some engines are really not moddable. I know , I have tried with some.

LE: Or perhaps you have a leak in the intake piping. If that is the case it won't make much of a difference anyway, but every bit helps.

i don't need to mod the ecu for the fuel as i use a FMU. and anyway hyundai ecu can't be modded because its the most complicated ecu ( i think only the genesis can be modded ). the only solution for fueling is fmu or piggyback. piggyback will cost 350$+ the unit and the tune wich can be from 300 to 900 depending of the dificulty they have tuning it. that mean AT LEAST 650$ on a car that i get rid of after this winter. worth it ? NO !

my piping the turbo my gauge etc will go on my futur elantra so was all worth it.

also there no leak at all. i checked 4 time.

back to THE problem.... i put the same turbo on my brother accent GS 2003 with is the exact same engine ( mine is MAF , his is MAP , but the same engine ) and i don't know for full boost yet but it spool way before mine. that mean the turbo might be correct. and that tell its my compression giving a problem ( i repeat , 302 000km on original engine and never been opened to change a gasket , pistons or anything ). worth it changing pistons and rings ? NO !
the only solution is then changing the turbo. the t28 will go on the elantra and if i buy a new one then it will go on my brother lancer OZ wich will spool quicker and he like when the boost come at low rpm. so changing the turbo is a great solution without real money loose.

the problem , again , is wich turbo will fix it ? a t15 is way too small , t25 i bet there not enought difference , but this is what i asked and got no answer.

if there no solution i will just drop the boost to 5-6 psi to hit the full boost before the red line. less power , but on snow where will be the difference ! if it was for summer then it would be another story.

i hope to find a solution before i drop the boost.

[stephenl9000]

This website here should help with chosing a turbo
http://www.junkyardturbos.com/
Don't be turned away by the name. The site has some good info. Has helped me choose a good turbo for my car with little to no aftermarket or information on the engine.

[darkjedi]

well if you ain't gonna keep the car anyway, don't bother. the turbo is ok, keep it for the elantra, see how it behaves with that engine. it should give 1 or 1.2 bars of pressure, i thinkk with the 2.0 l elantra.

[Daffyflyer]

Not sure if this helps but.. For MX5s we typically use T25s for good boost from low RPM (maybe 2500ish?) but they'll typically only do 140kw or so and run out of puff at high revs, T28 spools a bit worse (maybe more like 3000 - 3500 for serious boost) but is more like a 180 - 190kw setup.

[Daffyflyer]

Also - http://www.squirrelpf.com/turbocalc/

[NvidiaForTheWin]

well if you ain't gonna keep the car anyway, don't bother. the turbo is ok, keep it for the elantra, see how it behaves with that engine. it should give 1 or 1.2 bars of pressure, i thinkk with the 2.0 l elantra.

thats what i will do.

Not sure if this helps but.. For MX5s we typically use T25s for good boost from low RPM (maybe 2500ish?) but they'll typically only do 140kw or so and run out of puff at high revs, T28 spools a bit worse (maybe more like 3000 - 3500 for serious boost) but is more like a 180 - 190kw setup.

thanks daffy.
no it dont help. because hyundai 1.5/1.6 are know as the wrost breathing engine ( even if they took mitsubishi design and fixed some problem like the oil pressure on 4g63 aka g4gc ). so that mean even a 1.3 from any brand will breath way better than 1.5/1.6 from hyundai.
this is also why you see a big difference with a simple short air intake on hyundai.

breathing problem is one of the reasons they are so reliable even at this LOW price , and also why they have a bit less HP than mitsubishi version.
4g63 = g4gc ( 2.0L )
4g15 = g4ek ( 1.5L )

less breathing = less exhaust. less exhaust = higher spool !

i got a MP saying t25/t28 are almost the same about spool. like 100-300 rpm difference. but for mx5 if the t25 spool is perfect , a t28 should be better because the spool is very similar but compressor is bigger.


i will just stick with my T28 and try to net get bored of the lag.

[darkjedi]

It depends on the job you want the car to do. usualy a larger compressor will generate more power and more intake pressure, but will take longer to spin up because of the larger diameter , therefore mass, but also because it requires more power from the engine. these are good for high speed aplications, where lag , handling and respone are not important but raw power is. a smaller turbo is going to kick in faster , but will not provide the same amount of air, these are good for more agile and responsive cars as it does not hinder handling as much. I personally dislike turbos in petrol engines. A fast car should have a high revving NA engine. if you cannot extract more power from these bangers , get a small turbo in. A diesel can make great use ofa turbo on the other hand.

[NvidiaForTheWin]

It depends on the job you want the car to do. usualy a larger compressor will generate more power and more intake pressure, but will take longer to spin up because of the larger diameter , therefore mass, but also because it requires more power from the engine. these are good for high speed aplications, where lag , handling and respone are not important but raw power is. a smaller turbo is going to kick in faster , but will not provide the same amount of air, these are good for more agile and responsive cars as it does not hinder handling as much. I personally dislike turbos in petrol engines. A fast car should have a high revving NA engine. if you cannot extract more power from these bangers , get a small turbo in. A diesel can make great use ofa turbo on the other hand.

true. but diesel hate high rev and i think everyone here know that. it is the wrost way to go for poeple that like engine screaming , like me !
a diesel engine in the redline scream as a gasoline engine at idle.

personaly i dont like diesel. because a single part will cost the same as the car/truck itselelf ( well its a joke but its true diesel parts are way overpriced and not better than gasoline parts ) just compare the highest price gasoline fuel pump to the lowest price diesel pump. there you get the famous surprise.

also i HATE speed. well on the street.... its for dumbass. on a track tho i have no problem with that. i don't go on track anyway.
i put the turbo ONLY to add a bit of power ( 92 hp stock.. it's a joke ?? ) to get around 130-150 hp and the pleasure of hearing the snail.

if i get the time to work on it and everything , i suppose the project to be finished and running in a maximum of 30 days.
so from now to in 30 days , i will see if i can tolerate the lag or not.

[darkjedi]

All diesels, new ones especially use high quality forged internals that are larger and usualy much heavier than petrol counterparts made so to witstand the high mechanical stresses of a diesel. the fuel burns much slower than gasolinne so it pushes harder , but slower. these are the 2 most important reasons a diesel cannot rev high, but their aplication does not require high revs. a diesel has a whole lot of other advantages: high efficiency, broad powerband (pulls hard from 1700 rpm no matter the gear you are in, you may not have an exhilaratingfeeling, but a diesel will accelerate fast on the highway), will last twice as much as a petrol engine, you can obtain about 150 hp/l with easy modifications, can handle large boost pressures (I saw an Audi 2.7 tdi with 3.2 bars of pressure, you won't imagine the acceleration it provided) and are not unhappy if abused.