kreatekustomz

Ok so after reading throughout last night and today I have a fundamental understanding of obtaining data, reading compressor maps, and plotting data. However, I'm still not understand a few basic things that seemed to have been left out.

Garrett says that a general rule for every 1psi 9.5-10.5HP is gained. Now is this ADDITIONAL to the engine output before hand? So at 15 psi I should have a gain of 142-157HP? So for an engine at 120HP + 142HP I should yeild 262hp?

If that is the case how do I see people running turbos at lower PSI and high HP rating even at low compression ratios? I understand some turbos have a higher flow rate at lower psi, but how could I harness this into my calculations. I've been told anything boosting over 20psi will need 100+ octain or meth injection. was I told wrong? If this is true I want to keep psi levels in the lower teens with HP high but something isnt adding up.

On a side note. After looking at the Compressor maps of Garrett To4e 50-54-57 trims I seem to be hitting the surge line at 50% max RPM. here are my numbers for my b18a1. My peak HP target is 400WHP

CID- 113
PR - 2 (15psi)
8,000 RPM LBS/MIN = 33.8
6,000 RPM LBS/MIN = 25.4
4,000 ROM LBS/MIN= 16.9

50 trim seems to be a good setup for a 1.8l but if I'm only looking at 275HP according to Garrett then I need to find a different turbo.

OneBadTurboCRV

Your calculations seem off, even if you are using the corrected mass flow formula. Also I do not know your motor specifics but you should be closer to 110-112 cubic inches not 113. It will change your number somewhat but nothing major. What efficiencies are you using? It is a lot of math to deal with and I don't know what formula's you do or don't have so let’s do a double checking quiz...

What are your numbers for the following:

Delta T = ???
PR = 2.02xxxxx
For compressor Sizing:
Power in BTU per Minute = ???
Power = ???
.........
Pco = ???
Di = ???
R should be 53.3
Mf = ???
CMf = ???

If you answer all of this it will help see where maybe you messed up or are getting confused. If not then let me know and when I have time I will try and help you out. At the very least I will need your assumed numbers for drop across the intercooler and maybe a few efficiencies and your MAX RPM range you are going to run the motor.

kreatekustomz

I followed this.

https://honda-tech.com/forums/forced-induction-16/question-about-smaller-turbos-96443/

I havent read anything about needing the things you listed. I also followed some things on garrett's website "tech 103."

explain your acronyms...

OneBadTurboCRV

LOL, that is a lot to read but I did look it over and it seems like good info, you might have crossed your numbers somewhere...

I will do some checking and probably post what I get for you. There is a lot of math involved with bench racing LOL...

OneBadTurboCRV

You will have to run probably about 20 PSI with a TO4 mid-size compressor wheel to get those HP numbers you are looking for. Depending on what wheel you go with would probably determine whether or not you would have to use race gas at 20 PSI.

I would have to say something like a T3 Turbine 76 trim .60 Housing .82 A/R and probably a TO4e Compressor 60 Trim ...

I am no pro at turbo sizing maybe someobody else can chime in and recomend one for that motor. I usually do lower boost B16's...

Schister66

For 400whp, the 57 trim will be a great choice. You'll be in the ~18psi range to get there and should be able to do it on pump gas. I haven't ever followed the way you used...it seems confusing, but i applaud you for doing the research.

kreatekustomz

Well I started doing the research after I seen on a VW forum talking about the 57 trim garrett surging. Which according to the Map I found I would be surging around mid RPM/Full Boost.



here you can see I plotted my 3 RPM related variables into the graph and at full boost around 4K I will be on the left of the Surge line...

Even if I went 50 trim I will be VERY close to surge

kreatekustomz

Oh and talking about 400HP. If I was to bump my psi to 20psi I'm looking at

14.7+20 = 34.7/14.7
2.36 PR which sets the surge line further away from my first reference point.

nowtype

http://www.not2fast.com/turbo/glossary/turbo_calc.shtml

Don't even bother with the hand calculations. I've looked at enough compressor maps to know what turbos do and don't work well. 400whp you can pick any t04e turbo and it will be fine. The 50 trim is the only T04e wheel I would use. Then comes the 60 trim but at that point I'm more out to buy a SC61 or some varient using the GT40 comp wheel. There are a lot of other turbos better than the T04e family, but for ease of usage and cost, it wins 9 out of 10.

PM me if you really want to know how to read a compressor map.

kreatekustomz

can anyone help explain the theory behind why I'm tipping into the surge line? Everyone says the 57 trim is a good choice but my figures show otherwise. I have check my numbers 3 times now...

OneBadTurboCRV

Probably because you are figuring Full Boost at 4,000 Rpms? I have the same exact map and at least for my B16 it is more than away from the surge lines UNLESS I figure Max Boost at low RPM's 3-4k...

TheShodan

iTrader: (14)

You have to look at engine demand flow and multiple rpm points (about 10) to get an idea of what the turbo will do. 57 trims surge on VWs, DSMs, and Subarus. They do not do that on Hondas due to the characteristics of the engine.

Don't treat Hondas like any other engine. they aren't the same.

grndcont

i dont know if it helps, but on my 18c1 i think i'm surging my to4e 60 trim @ 3500-4500 rpm, boost is around 5-7 psi. sounds like a couple of pops coming out of the turbo inlet. i was thinking of trying a 57 trim to see if it stops as i have not heard of any surging with the that one.

i was doing the same thing you are a few years ago when i was trying to decide on what turbo to get. seems like the factors to consider never stop.

TheShodan

iTrader: (14)

grndcont: the exducer size of the 60 trim and 57 trim are the same exducer size, so your surging issue seems like it would be from something else. Simply changing turbochargers more than likely will not solve your surge issue, especially at such a low pressure ratio. You may want to look at some other factors, such as vacuum lines and leaks, your BOV hook up, and the condition of the turbocharger itself.

kreatekustomz

N3v3sati3fi3d, I was figuring full boost at 4k because I its my understanding you can expect FULL boost at 60%. Most people from what I read calculate full boost at 50% of max RPM.

I've also noticed I there are different stage wheels for the To4e 57 trim. What would be the difference (physically and character wise) between stage I, II, and III?

If say I was to buy a 57 trim .68 a/r turbine with 60 trim wheel and I started surging around 3500-4000 RPMs. What are some factors I could consider fixing or CHANGING to limitate the surging? I'm assuming IC piping, Intake Mani, TB, Exhaust. Whatever gets the motor flowing better correct?

So assuming you have everything right from the start I shouldnt have any proplems with surging to begine with?

Lets understand that my motor is a
B18a1 81.5mm
wiseco 9.1
eagle H

B18B head
KMS valvetrain
Crower 402T cams
PnP

Top mount
3" dumptube no exhaust
2.5" IC
Stock TB, Intake Mani

kreatekustomz

after looking at the T04E 60 trim the surge line seems to be much much smoother. So I looked into the turbine which is the exact same as the 57 trim? I'm wondering what the difference is in the two turbo considering they both have the same wheels?

here is a map of the 60 trim and my plotted data which seems to be very efficent at max RPM...

kreatekustomz

SOOOOOOO 57 Trim or 60 Trim thats my optioins!!?!!?!!

grndcont

shodan, thanks. kreatekustomz, sorry if i thread jacked.

for your question, i've been very happy with my 60 trim, but the current trend is to run a 57 for low buck turbo. i dont think you could go wrong between the two.

Tjabo

Could you please elaborate? This is something I've been wondering about a lot, and I'm hoping you have some theories at least to share. FWIW (which is very little), my theory is that it's because the Honda engines in the range that are the normal subject of this board are tuned for higher RPM operation (and thus higher RPM peak torque and HP) than DSMs and the like, and thus push up against the surge line less by spooling a little later. This would also tend to explain why the HP numbers out of them are soo good, and why they are relatively resistant to detonation. Yes? Or no?

kreatekustomz

well the 57 and 60 trim is the same price...

OneBadTurboCRV

Honda's were pretty much the pioneers in head and casting technology for vehicles. When Ford, Chevy, Chrysler, and others started designing motors they pretty much put all components first before they placed key things like the intake and exhaust ports. Have you ever noticed how direct the exhaust and intake ports are on Honda heads? They were one of the first to lay out the ports before they started placing components. Not only that but the way they casted their heads and blocks made quality a lot better and copies of the original model much closer. They manufacture parts under stricter standards then the domestic counterparts as well. Being that Honda heads flow so well from the factory and little is needed to improve upon them they are in a league of their own. Let alone the VTEC that has changed the way motors to this day are made. After Honda made VTEC everybody tried copying them with things like Mitec, Zetec, and ect. The increased flow from head design and the ability to have a "bigger camshaft" on the fly enables drivability/economy as well as the ability to still make power at higher RPM's. There is plenty more but this should give you enough of the basics to fill in the blanks.

non-VTEC

you can try to read compressor map and calculations until your blue in the face. i spent countless hours reading up on all that crap years ago. that stuff is best left for the engineers who designed them because it makes sense to them only.

like mentioned by other users. any of the t04b/e/s 50/57/60 trims will get you 400whp with the proper tuning.

there are countless setups running those turbo's at those power levels......do you think any one of those guys are concerned about surge limits and compressor maps?......**** no.

here is my 57-trim to4b ripping 440+whp http://www.youtube.com/watch?v=bqlzRA6yOSc

nowtype

That isn't close to answering the question. Try again.
__________________________________________________ _________________________________________

Here's how I do things and it works.

http://www.not2fast.com/turbo/glossary/turbo_calc.shtml

Here is the deal folks. Pick how much HP you want. Say it is 400whp. That means you need to find a turbo that will flow 40lb/min. So draw a vertical line up from 40lb/min. Now you will need to draw some horizontal reference lines. You want to start drawing lines where the line will intersect with your 40lb/min line on the compressor map. If you aren't finding points intersecting on the map, the turbo is wrong. You want the peak number to fall towards the right of the compressor map so keep in mind if your dead center of the compressor map but you only have 10lb/min of room to the left, you won't have much of a power band.

Now you have to use a bit of your brains. You have to analyze which pressure ratio works best. Now this is where you have to actually understand how your engine works. Some engines make peak HP at around 5500rpm and either hold steady or die off afterwards. This is due to head/cam dynamics which creates a peak VE at 5500rpm. Understanding this means you understand that at 5500rpm your engine flow needs to be 40lb/min in order to hit your 400whp goal. With B-Series Hondas, it's a bit different. The torque is flat unless the turbo screws with the VE enough(running out of steam/becoming restrictive). So from when it hits peak full boost to redline, you can pretty much say your VE is the same because your torque curve is very flat.

So practical calculations. You have a B18a1. Without any head work, you will have a peak VE at around 5500rpm and hit max hp at around 6500rpm. I'm assuming you are running a stock head. Now this is where you have to do clever calculations. I'm first going to find what pressure is actually reasonable to expect 400whp. I'm going to use the RPM of 6500rpm as where I expect that to happen. Why? It's how the VE of the LS head works. So now its time to guess what the VE will be at 6500rpm. The best thing to do is guess and see how the numbers work. A good number to be around is 100-120%. Typically Honda engines run about 90-95% VE at peak HP. Turbos simply increase VE so a 20% increase is expected. Use the plotted information to pick pressures that will hit 40lb/min. I found that between 20 and 22psi I can expect to make 40lb/min with a b18a1. So now I have to look at where that lands on the compressor map. Draw a dot or something.

Now you have to figure out when you will hit peak boost. Assuming the turbine wheel is balanced to the compressor wheel, this will work. If you have some turbo with a huge compressor wheel and a tiny turbine wheel or visa versa, this may not work very well. Turbo manufacturers don't do that too often so this should work 90% of the time. So out of laziness I'm going to say we are going to run 2.4 PR (20.58psi). I should already have a line at 2.4PR. Now I'm going to draw another vertical line down where the compressor map and 2.4PR just touch on the left. This is the amount of air the engine must flow to get to full boost. Time to guess at the VE. Using the b18a1, I'd say its around 100%. Set your VE to 100% and the boost pressure to 20.58 and start punching in rpms until you get the number you are looking for. Now you have your extremes and you can figure out anything else you need by working in between those values.

Duende

i'll go with the 60 trim....handles more and spools about the same

kreatekustomz

Nowtype, I understand your concepts and infact I was implying what you are saying to do. However; I calculated not for the desired HP but the desired PSI level. I'm wanting to keep the car on pump gas with no meth injection (at least right now.) and I'm still looking to hit 400HP. Now I know this is possible but when I'm adventuring into the 20+ psi level I realize I'm getting into the danger zone.

So I guess what I need to do is look for a turbo that has a the desired cfm of 400HP at say 18psi which from the maps I have seen looks like the GT30 would be what I'm looking for but not for my pockets.

Also my head is far from stock with max pnp, KMS ultimate valvetrain +1mm, 402T Crower cams and adjustable gears. Giving that I realize the motor will flow better thus increasing VE. I'm going to go back and recalculate at 120% and at different PSI/HP figures. Also you said I need to "guess" what max boost level is. Would it be safe to say Honda's max boost can be achieved at 60% max RPM level?