R.E.Developement

hay i got a 92 civic si with a gsr in it i also have a small turbo steup for it but dont have injecters or fuel pump yetif my goal is to get 300 hp max what size injecters should i use and i know that ill need a fuel pump and some what type of fuel tuning device such as a vafc.

help me out. thanx

pissedoffsol

255 pump
550's

on a small turbo, you're going to need way more than 10 psi for 300 hp, so, ditch the vafc idea.

hondata, 3bar map, dyno time.

D See 2

he covered that pretty well. Brian knows his b00st!

liquid00meth

on a stock block your going to get about 300hp worth of rod through your block, thought.

pissedoffsol

ehh, tuned correctly, it should hold 300 for at least a little while

cycloneb18c3

i heard that right around 350hp everything stock starts breaking(internals wise rods, rings, etc)

beerbongskickass

http://www.boosted-hybrid.com/viewtopic.php?t=82

Honda/Acura motors tuned right can make a lot of horsepower and be very reliable.

Slammed90Lude

Geoff at full-race showed me dynos of stock gsr's making 345 reliably and that have been running for two years plus

there is no reason you shouldn't be able to get 300hp from a stock block, get a thicker head gasket if you're worried about it- or run a profec with high and low boost levels and stay off the high boost level unless you're on the track to prevent unnecessary stress

Import Builders

I think we hold the record, but I am not sure.

Stock GSR block, not sleeved, with just pistons, running almost 20 PSI running 11's for like 6 months in a street car.

Then we got another one on a comepletely stock GSR longblock with over 100k miles on it boosting 10 PSI making 330+ WHP with our turbo kit on it, running 11's.

for 2+ YEARS now! haha

then we got another 1.8 Liter LS/VTEC with stock sleeves, with IB Spec Wiseco pistons running 10 PSI on the stock map sensor making 370+ WHP running for:

3+ YEARS NOW! haha. But he only runs low 12's because its a 4 door boat.

And all 3 get 25+ MPG daily driving.

Its not the HP that kills your block, its the boost level. Our stuff is effecient, so its easier on your motor at lower boost.

Its all about the turbo kit you get, and who guides you. You could put the same turbo kit on your car, get 2 pieces of bad advice and literally be 75 WHP at the same level of boost lower than the other guy who spent the same amount of money.

Also, your stock GSR fuel pump is good for 375 WHP at least, because all of the above cars are running on stock fuel pumps with RC 550's, and 1 of them has the stock single cam pump.

stock fuel pump is awesome.

Jeff

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liquid00meth

I agree, good examples. I just strain to reccomend 300 or more on a stock bottom end to anyone who is newer. It's easy to make a mistake that costs lots of money at that level

saturn_boy96

jeff knows his stuff. the ib site has a really great article on boosting, if you haven't read it you should.

ndogg

huh? can you explain this? as long as your intake temps aren't rediculous... i'm going to argue that hp kills motors... not intake pressure.

to the original poster... what turbo are you running? and 550's will easily get you to 300hp. people have run 450's to over 300 but that is VERY close to maxing those things out. it also depends on how much base fuel pressure you are running. with the 450s you may need to up the pressure... 550s should be good with the stock pressure and stock 1:1 regulator.

Import Builders

I will argue my position by asking you to explain to me how a motor knows the difference?

GSR A with 10 PSI
GSR B with 10 PSI

A makes 250 WHP because its got the wrong parts bolted on to it
B makes 320 WHP because it has a better exhaust, intake manifold, etc.

they are both boosting 10 PSI..

Why exactly is motor B more stressed? they both have exactly the same everything, air/fuel ratio's, everything tuning wise.

Jeff

ndogg

turbo A is obviously the smaller turbo and flowing less CFM. your engine makes more power when more air and the proper amount of fuel is combusted. so it doesn't matter how much pressure is in your intake manifold. what will matter is the total number of air/fuel molecules in the combustion chamber. psi does not directly dictate that value. its all about the CFM. this is assuming that you are not off the deepend of the compressor map and running rediculously hot intake temps.

so if turbo A is not producing as much power it is because it does not flow as much CFM at a given psi level. this can be compensated for by turning up the psi so that it does flow the same CFM as turbo B. does your motor care how much psi there is? not really, the psi doesn't really make much difference to the peak cylinder pressure, the total amount of air and fuel do.

Judo_boy_48

Im thinking he meant that the turbo is also the same size.

ndogg

if the turbo is the same size then you are loosing molecules of air somewhere else. like the intake manifold is not flowing as much or the intake temp is higher on motor A making less molecules/volume. if the exhaust is more restrictive on motor A...then that turbo will be flowing less CFM?

... and the rest of my post still applies.

power is all about the amount of air molecules present for combusion.

MikeBergy

Unless you are running a stock civic cx exhaust, your turbo will spool the same amount, just take longer to do it. CFM will be the same if the turbos are the same, and are both boosting at 10 psi. period. Law of mass conservation, look into it. The intake air temp does affect it though, but if both motors have the same setup, and are subjected to the same conditions, tuning is what is going to make the difference in how long the engine lasts.

Jeff, if you make 320 hp, as opposed to 250, the extra power produced is going to introduce more energy into the system. You cannot tell me that an increase in torque is not going to produce more stress upon the bearing surfaces and piston rings and cylinder walls. More power just increases the stress. Now if you are talking about the total amount of power at the wheels, that is different, because you are introducing parasitic power loss into the equation.

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ndogg

IB - i read your writup on the turbo. i must say, it is a very well writen and infomative artice. much props. the one problem i see is related to this thread.

you say:

Throttle Body/intake manifold. You’re going to want to go with a large plenum intake manifold such as the Edlebrock, JG, or other intake manifold. That will make considerably more power under boost than your puny, stock intake manifold that was probably designed mostly for throttle response. Your turbo piping on a sophisticated turbo setup is probably 2.5 inch pipe most likely. All the street legal kits I have seen are smaller at like 2.25 inch pipe. People, huge throttle bodies do NOTHING on turbo motors. 2.5 inch pipe is 63.5 MM in diameter. But still, that doesn’t even matter because as long as your intake manifold is pressurized, the engine doesn’t know the difference. Your boost gauge is hooked up to your intake manifold right? Does it read a steady 10 PSI? Then that means your intake manifold is a steady 10 PSI, so why is a 70 MM throttle body going to do a damn thing? Get the picture?

in that paragraph, you say that the TB doesn't matter because as long as the manifold is reading 10psi... then upgrading to a 70mm will not do anything. i agree that TBs are not a good hp/dollar investment for boosted motors.

but, you also state that the new intake manifold is a good improvement. and i agree, it is a good hp/dollar improvement. but by your logic, it shouldn't be... because the manifold pressure is 10psi with either manifold right?

you see the contradiction? i agree with both statements, TBs are not worth it, and intake manifold yeild good results... but your reasoning is flawed.

now do you see my point that PSI is just a relative term, the new manifold actually flows more air, thats why it is a good improvement. where as the new TB does not flow much more air, thats why it is not really worth it.

besides that, its a nice writeup!

Calesta

It's all about pipe tuning. Do you know anything about it? The intake manifold still matters quite a bit. It still controls the ultimate flow pattern or "shape" of the air that's going into the combustion chamber. Go read a fluid dynamics book or something.

radnulb

I'm surprised no one has mentioned headwork. The final passageway that air needs to go through before being useful is often the main bottleneck. Headwork that significantly improves air flow almost always has a dramatic impact on power production. I expect that I will make 8-10% more power at 8psi with my heavily ported LS head (200+ CFM/port) with the same cams, pistons, etc than I did with the stock head after retuning. Same boost level. Same turbo. Same IC. Same bottom end. More power. Why? MORE AIRFLOW. Boost is effectively a measure of airflow resistance. To reach the same boost level with a system that has fewer restrictions requires more air to be shoved through the system.

Calesta and ndogg both have valid points on the TB/Intake manifold issue. I think that it is fair to say boosted motors respond much LESS favorably to things like larger throttle bodies, bigger intakes/chargepipes and other airflow targeted modifications than NA motors which rely on suction from the engine's pumping action to deliver air to the cylinders. The reason I was told that airflow mods give (relatively) poor Return-On-Investment is because the turbocharger (if limited by a specific PRESSURE) will simply work harder (without you being aware of it) to achieve the same boost levels in order to compensate for a crappier flowing charge pipe / intake manifold. Think from your valveseat backwards: If the head can flow 210 CFM / port, you better make sure the Intake manifold can flow the same, and the TB can flow the same and all the way back to your compressor. If your head is the main bottleneck, you'll see few rewards from the bling-spec intake manifold and throttlebody.

Turbo motor reliability boils down to internal engine forces.
Accepting this premise, ndogg / MikeBergy appear to be most correct.
Torque initially would appear to be a better guage of engine wear than HP, but he who forgets sidewall loading forces (and piston-ring-cylinder wall forces) increase with the SQUARE of RPM will quickly remember after his motor blows up.

Jeff has / is / will build some solid cars, but physics doesn't change for engine builders, or Import Builders.

Boost level is a BAD way to guage how long a motor will last, in my humble opinion, because there is no explicit correlation between boost level and airflow. Airflow + fuel = torque. Power = Torque / unit time. Power seems to be to be the best easily measured indicator of internal forces because all of the forces that factor into the calculation of power output either directly or indirectly factor in to internal engine loads which are most directly attributable to engine failure.

Beyond 300 I'd start looking towards rods+pistons at a minimum, but that's just me. Insurance never hurt anyone.

Disclaimer:
This is just my opinion, my perspective on these things. It's what I use when judging what parts to buy for my car. It's what I use for judging what mods to do to my car. It's what I use to try to hit my power + ET goals. If you don't agree, please try to be contructive and encourage discussion of technical issues so that this minorly argumentative but quite informative thread can continue to bring out good thoughts and ideas from everyone.

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MikeBergy

Only those with shallow pockets.

power losses can come from anywhere in the flow path, From filter to fart cannon. You have to be able to increase the flow everywhere in order to maximize the flow, and thus power.

radnulb

at 8psi, almost every turbo on one of these cars is going to be operating with the wastegate partially open.

The wastegate partially open implies that the exhaust gas flow from the motor exceeds that necessary to generate 8psi of pressure.

With a crappier flowing charge pipe / throttlebody setup, the wastegate will simply open a little less (making the turbo work harder) to reach similar pressure levels.

For a naturally aspirated motor, there is no turbo. A scavenging header can help make good use of exhaust pulses. A set of tuned ITBs or an intake tuned to a specific frequency / RPM can help stuff more air in the motor. There isn't a magic air pump to cram more air in there when you fuck up some minor detail like there is with a turbo car.

Turbos aren't free - they rob the motor of VE in order to spool and feed air. You forget that exhaust gases bypassed by a WASTEgate are exactly that - wasted energy that COULD be easily used to work the turbo a little harder in the case of crappy flowing stuff.

That is a more clear and concrete example of what I spoke of above.

I think I am speaking to ROI / point of diminishing returns / cost effectiveness more than absolute theoretical best thing. If given the choice of spending $300 on rods or $300 on a bling spec intake manifold, I'm going to take the rods and crank the boost up twice as high as it was before. If I had a massively ported head, I'd want to match it with a higher flowing manifold. (I'm trading my B18A manifold for a Skunk2 when I put the ported head on)

It might be a good study to examine the flow of stock intake manifolds vs. stock heads...

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Joseph Davis

Wrong.

Your point is not well taken, because it is not what it seems.

In turbocharging, you manipulate pressure differential to acheive your desired cfm - cfm *is* horsepower. As long as you are on your compressor's efficiency island, it cares not one whit if you make your desired cfm at 8 psi or 12 psi, and neither does your engine.

Flow restrictions bolted to engine A result in less power - a good example of this is a log manifold versus something with a long, smoothly transitioned collector. Especially given how runners on the log manifold don't evacuate each cylinder evenly... taking average AFR for all four cylinders results in leaning one cylinder out when it comes time to push some limits. Is this due to the amount of boost you run? No, but the amount of boost you run may be a sympton of just such a thing happening if you don't have your head removed from your ass, and can't look at the big picture.

There's a lot of stuff going on here; how cam timing combined with manifold pressure manipulate dynamic CR... the same thing with cam timing and TIP on cylinder evacuation... etc... that influences your net result. You can say truthfully, and with much applause from me, that the setup on GSR B makes more power more reliably than other setups for that engine, but you cannot say higher boost numbers are bad to sell more headwork and fancy valvetrain. There are loopholes to that statement in practice, in day to day application, and in the physics dictating how things work behind the dyno plots and PR releases.

Bottom line, if my bottom end is capable of supporting X amount of power, I can achieve it with a stock unported head just as well as a fancy ported item. I have to run higher boost to do so. So what?

Brad Z (sound familiar?) told me the current record for a stock LS head is 850 whp. It was, of course, perched on top of a bottom end that could hold it. That right there sold me on not worrying about flow numbers or boost numbers (or $2000+ dropped into your cylinder head) as long as my flow is balanced, and what I bolt to the engine is well thought out.

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Citizen_Insane

You also have to realize though, that running more PSI in exchange for a poorly flowing head is putting unnessisary strain on the whole system.

radnulb

you missed the man's point.

CFM (Airflow) = power

It doesn't matter if you sit at 8psi and 500 CFM or 12psi and 500 CFM - as long as you're not pushing your turbo outside of its efficiency range, you'll make the same amount of power with the same amount of airflow.

Power is stress.

For example: my LS motor will be under more stress at 8psi with the ported head than 8psi with the stock head because the ported head will flow more air, and airflow NOT pressure level = power