slatermvp

iTrader: (13)

Amby I agree with you that maybe the 180-200 whp might be a steep climb but I do not believe that he will see minimal gains from his set up. You did only see 5 whp increase but then again if I remember correctly from reading threads, and correct if I'm wrong, but you weren't tune. With his car being aggresively tuned he should see a higher hp increase then what you saw.

I definitely can't wait till its done though. This will be the first time that someone will have gone this extent on their motor on this thread with NA. This will also finally show how responsive the DOHC swap will be to mods.

Midnightkid

I admit, 180-200 is pretty ambitious; but building off of what Slater stated, I've done a lot of research during my deployment and looked at this not just from a tuning standpoint, but an engineering standpoint as well. While 4G93/94 hybrids have been done, a majority of the builds were all turbo'd. Planning began back in the fall of 2010 when I picked up the head. I didn't pick up the first part until months after, when I did thorough research into the pros and cons. While I'm not saying I did wind tunnel or anything, aside from the shops that are supporting this build, I've also had a lot of support from the melting pot community of the Army.

I'll definitely do an extensive review of the swap. Aside from that, I'll also do reviews of individual parts I've installed over the year. While my build is focused soley on All-motor performance, I believe a DOHC head swap will also open up new potential for turbo'd applications as well.

ambystom01

iTrader: (7)

The stock MAF isn't a huge choke point on an NA build. I've yet to see any conclusive evidence showing it's a choke point in all but the highest HP settings.

Based on the power curves, I wouldn't pull ahead a substantial amount. They were virtually identical save for a higher peak value that can be attributed to my exhaust modifications. Such is a nature of NA mods. There isn't one mod that will somehow bring the entire setup to life (ie. if I had added a different MAF I wouldn't suddenly be up 20 WHP). Everything works together in contributing small amounts here and there. In some cases, the restriction just isn't enough to see big or even noticeable gains; if the car isn't starving for air, a bigger IM or TB isn't gonna do a whole lot. An engine can only do so much.

Personally I question your datalogging if you're noticing substantial changes by just shifting the intake slightly. That to me suggests there is something wrong in the way the data is being collected. Logically it doesn't make any sense that shifting an intake slightly would show measurable changes in throttle response.

I'm not saying you won't see power gains. You should see pretty good power gains based on the extensive nature of your mods. What I'm saying is to be skeptical and not accept the smoke that is being blown up your ***. A shop is telling you you'll see double the stock HP using relatively mild mods. That seems a bit off to me. I wouldn't be shocked if you hit 130-150 WHP, which in itself would be an accomplishment but those next 50 WHP is going to be difficult, if not impossible. If you go in expecting 180 WHP and only get 130 WHP, you could very well be disappointed or start blaming the build.

Demon_ni2

iTrader: (15)

for a highcompression.. i would say 150 on pump. 170 on e85 or race gas would be the realistic power goals. or 220 on straight meth, but thats not legal for street or scca SM. also nitrous isnt legal at scca events, so cant be added or figured into power goals.

Demon_ni2

iTrader: (15)

if u look into the euro world more the dohc 4g92/3/4 are known for making 170ish hp. being that a 1.5 120hp, and 1.6L dohc makes 140hp stock. and ur dropping that head on a 2L with mods! 170hp goal with other mods is realistic. just saying, check out some of the highcompression 4g9x JUN euro and jap mirages. there some nasty little low revving motors. its not far fetched for 180 goal, and still not a big goal for street gas really. i was huge into the NA scene before i went boost, and knew exactly what i wanted to do if i stay with the 4g9x series motors.. but since im more into the Pro scene now, i would go 4g6x family and hope for the best on meth with NA, but i waste to much money on cars and dont care about streetability really.

ambystom01

iTrader: (7)

170 HP is realistic, 170 WHP is not. Like I said, I wouldn't be surprised if 130-150 WHP was possible with his setup but getting into the 200-220 HP or 170-200 WHP range is a bit too optimistic.

Demon_ni2

iTrader: (15)

amby, all i can say it.. check out overseas.. 170+whp.. on smaller displacement with same head. or checkout PR guys, running 10s maken 220+hp(race gas)

our detuned 4g94 motors are crap. ...... 11:1 + dohc + real mods.. decent power made easy.. its like ur basic b20 build. LOL

ambystom01

iTrader: (7)

When it happens over here, I'll believe it. Unless we know the exact nature of the builds, we really can't compare them. For all we know, they're running way higher compression with hyper aggressive cams, among other things. I don't think the build here is aggressive or extreme enough to net those kinds of gains.

Demon_ni2

iTrader: (15)

probably right, off the batt with minimal mods ur right, it really just depends on how competitive some people are..

exspecially since POWERS MEANS NOTHING in scca autox.. and ur dumb to be in SM(just sayin) u should be fucsing on Hstock or SS. sm is actually where most all modified awd cars go as long as there full interrior. i ran SM for 2 years basically, and was never really competitive since i was in a serverly outclassed car.. thats why i bumped myself into EM(emod/extreme mod) cuz there isnt that big of a competive scene for that, and im not worried about the cars that show up that run that class.(although national scene would destroy me in EM)

ambystom01

iTrader: (7)

Autocross seems to be all about finding the perfect car for the exact class you want to compete in or finding the perfect class for the exact car you want to use. Hell, my Miata is way the **** up there in class because it has modifications needed for track use, like an aftermarket steering wheel. If I was going to do it all again with autocross in mind, I'd build it to within an inch of the CSP rules.

Midnightkid

@Amby ... You'd be suprised with how air reacts in terms of fluid dynamics given it's environment. In my case, I have a short ram intake. At the angle and height it was positioned, it's ability to collect ram air was dimished regardless of the vacuum that an intake produce. Optimise the flow of air while minimizing turbulence and you can see improvements you didn't realize you can get. The intake I have now is good, but can be improved. I plan on getting one made once I do a battery relocate, in order to make better use of the space.

As for a MAF sensor being a choke point, it's the same logic as a pinch in a garden hose. While the pinch isn't as severe, it's still an obstacle that air has to slow down for in order to pass through. I'm not saying it's going to give you monster gains, but it'll improve the efficiency of airs path into the motor. Minimize that slowdown in air and match the vacuum an intake produces, and you're throttle response will definitely see some improvement.

@Demon, that was a mistake on my part. I competed in the Street Touring class (The last time I ran was 2 years ago right before I left for Basic so my memory's a tad fuzzy lol). When I get back, I'm probably gonna try the Street Modified class since ST nor SP don't allow modifications to the motor itself.


Back to the topic of my build, Update from the shop. They had to regrind the part that came in (I can't remember what it's called off the top of my head, but it's the half-moon looking part that secures one of the cams) since it had a 95% fit. Shouldn't slow down the build significantly, but it is moving foward. Being where I'm at, any news is good news at this point lol.

ambystom01

iTrader: (7)

Look, I'm not new to modding cars, I've been doing it for close to a decade so I would appreciate it if you'd stop trying to explain basic tenants of motors to me. I'm well aware that air behaves like a fluid and in some cases in complex ways. However, we're not talking about redesigning the intake, it's an SRI. We're talking about moving it a few inches. Assuming that it's something like the RRM SRI, I honestly cannot see how that would produce substantial and, critically, detectable changes in throttle response. The size of the piping is the same, the basic shape is the same and the filter is the same.

The MAF is only a choke point if the motor can use extra air, ie. it's only a choke point if the motor is choked for air. Hell, if throttle response is what you want, going too free on the intake or exhaust side can hurt things. This is part of the reason why tuning ITBs can be a bit of a pain in the ***, you need to think about the size of the trumpets.

Midnightkid

I'm not trying to insult your intelligence or anything and I'm honestly engine retarded which is why I'm having a shop build my motor. But what I'm talking about are seemingly simple, yet complex principles of Aerospace Engineering that I've studied and majored in, and cramming a decent amount of knowledge in a few sentences. This isn't a physics forum so I'm not gonna break things down hardcore. But even with the size of the piping and filter being the same, the path air takes can vary. You've done autocross and you know that a you can have the same person drive the same car but take a slightly different line around a corner at the same speed, and yet the time around the corner can vary between a fraction of a second, to full seconds. Air is the car, the track is the intake, and the line you take around that corner is the path air takes to get into the intake. That's pretty much the best way I can compare it without speaking nerd talk lol.

As for the MAF sensor, if you're at cruising speed and suddenly floor it, the engine is going to immedietely want as much air as you can give it. I'm not trying to say that something as trivial as switching out the MAF sensor is on the same grounds as going from stock to turbo; but every little bit helps, even more if you can make those little bits perform together. And just like you said, too much exhaust is a bad thing for the sake of back pressure. The intake on the other hand can be a bit finicky because the ECU can regulate the throttle. I'm not an expert at making horsepower, but my area of expertise is making things work efficiently. Throttle response won't be the reason I run 15's (not literally, I picked a random time)in a 1/4 mile, but it will be a reason why I can slash off a second during a lap around the track.

ambystom01

iTrader: (7)

The two are not analogous. Air in a tube does not behave like a car at an autocross. The reason why different lines work has to do with entrance/exit speed and making the corner as short as possible. If you haven't physically changed the shape, size, composition or location of a tube, I do not see how you can notice dramatic changes. Imagine water in a hose. Barring any major problems, it does matter if you make relatively small changes to the positioning of the hose. How are you even measuring these changes anyways?

The car will only want as much air as it can use. You could bolt on the biggest IM possible with the biggest TB and the biggest MAF and you're not going to see power differences over a much more sedate build. Why? The car simply can't use it. It can only take in so much air under it's own vacuum. Moreover, you may see a lose in power and throttle response because the engine has so little restriction it can't effectively draw in air as efficiently as possible. If you aren't choking the engine, opening up the intake is pointless. If we say the engine is just a giant air pump, if it can only move 20 units of air per unit of time, and the current system is capable of providing that, modifying the intake system to handle 50 units of air won't do a damn thing because the engine or pump itself is the choke point. This is where modifications like head work and cams come into play. You allow the engine to move more air. Having huge cams without the supporting intake and exhaust mods is pointless as is the reverse.

What are you talking about the ECU "regulating the throttle"? I don't see how that is relevant. WOT is WOT. Some engines can control the throttle to a degree but you have a cable driven throttle system, not a drive by wire system.

Throttle response to some degree affects lap times. However, it's more about preference than anything else. You can work around throttle response in the same way that you can work around turbo lag by applying throttle earlier.

Midnightkid

I'm not trying to speculate or state my own theories, what I'm bringing up are facts and laws regarding fluid dynamics that even have formula's to calculate them. The reason why I chose the Autocross comparision is because it's something we have a common ground with and that in the case of a vehicle in motion, air in this instance will act with respect to velocity... speed in a given direction. The hose comparision would be good if I were refering to air inside of an intake, but I'm talking about the path air travels to get into the intake. Granted air is a fluid and will conform to it's environment, you want to minimize the resistance you give air to optimize it's path of travel. I can't remember off the time of my head what metric I used to measure it, but readings in EVOScan as well as some number crunching that I did to see if there were ways to improve efficiency are where I based these figures . Here are some factors that optimized the efficiency my intake worked, with respect to lifting my intake:

1) Adjusting the height essentially modified the angle. A few inches lower with a downward angle of let's say 45 degrees, air has to change it's path of travel to conform to the 45 degree slope. Even with vacuum involved, the efficiency of air travel is affected. Lifting it a few inches and changing that angle to 25 degrees, air doesn't have to adjust as much to the angle and it has the ability to maintain that velocity.

2) With the intake essentially facing the direction of travel of the car, and the slope of the intake is roughly leveled with the plain (in respect to the car), air can maintain foward motion. Less work for air to take, along with the vacuum of in intake is better efficiency.

3) At a downward slope of 45 degrees and without the aid of vacuum, only a fraction of the amount of air would enter the intake. With a downward slope of 25 degrees, a greater fraction of air would enter the intake without the aid of vacuum. Put vacuum into the equation and air travel is more efficient.

Again, as I stated in the past, I'm not making horsepower by lifting my intake. I am saying it improved airflow, which in turn, improved my throttle response by making the air do less work to get into my intake.

As for the whole choking thing... You are absolutely right. An engine can only take up and process as much air as it can contain and utilize. Too little and many restrictions can adversely affect power and throttle response. Having larger anything will only see minor benefits unless significant work is done to the head to support those mods. But at the same time, it's how fast an engine can process and cycle, that intake and exhaust mods are truly beneficial is what I'm trying to get at. An engine may only be able to process 20 units of air at a given time, but things change when its processing 20 units a minute versus 20 units per second. It's a delicate balance and it's something that I doubt I will ever perfect.

With the whole MAF sensor being a choke point, I'm an air molecule passing through the 10 lane intake (given Velocity). Here comes the 9 lane-toll MAF sensor, I need to slow down along with these other air molecules so I can get through the MAF sensor (change in velocity). I'll pass eventually and it's only 1 lane, so it's not a big difference. But the air molecules on the 10th lane need to switch lanes, thats no good... in fact, they're squeezing with air molecules in the other lanes to pass (Turbulence). Now it's affecting how fast and how many air molecules passes through even though it was just 1 lane. Again, not saying making power, but improving air flow.

And ECU regulating throttle... I dunno about you, but during my real-time datalog sessions, the most I've seen is 97.5-ish% WOT at around 5000RPMs (off my memory, not too great BTW). As my speed increased, that number dropped down to 87%, then 80%. Whether it's the ECU or not, there is some sort of regulator in place to control throttle position. Pedal to the Metal, I have never seen WOT stay consistant for long as my speed increased. This may be an isolated incident and may be only my car, if thats the case, I'll retract my statement no problem.

As for Throttle Response and Lap Times, you're absolutely right. Throttle Response is a preference of mine and something that I factor into driving. Autocross is definitely a form over function kinda thing where drivers use ther tools at their disposal and make it their own. Not too many people appreciate that enough.

As for everything in general, I'm not trying to debunk everything you say because a lot of your words hold truth to them. However, there are some things that you, as well as people in general, don't take into consideration that could prove beneficial to your/their builds. Everything I've done is the product of research, experience, and everyone's favorite: Trial and Error =)