Honda Manifold Mod????

[TommyV]

Hey whats up DSMTUNERS? Im pretty familiar with imports and have had numerous in the past. Recently my barber asked me if i want to buy his 95 eclipse. He said its overheating he dont know why. Thats no biggie, I was gonna start by flushing the system, changing the thermostat(maybe just removing it(ultra low budget!). Hopefully its not the waterpump or head gasket. I'm probably going to buy it tomorrow for somewhere in the 100-200 dollar range. its no beauty but the shell is fine. good beater assuming i can quick fix the coolant system. ANYHOW the reason i joined was to search for tech, but i started this thread to ask a bizarre question.----

i drove a 88 mpfi civic turbo for a while and i still have the kit. heres a couple of pics

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the manifold fits all d series sohc hondas, i believe its a xs power?, MOVING ALONG...if i buy the eclipse im gonna have to put my kit to work!!! so i was searching around this site and found this thread http://www.dsmtuners.com/forums/articles-turbo-system-intercooler/181134-how-build-420a-stage-2-turbo-kit-under-1000-a.html and started thinking could i just use this peice

(just the template of the exhaust manifold welded onto xs power civic manifold????) and use the rest of the kit.

i've seen honda kids do the opposite, cut dsm manifold and weld honda templates on it, full eclipse turbo on a civic.

my turbo kits real basic t3, turbonetic wastegate, fmu, DSM BOV !, oil lines, pipes ect...

the only coflict i can see is the maniflod,down pipe, maybe engine management. by the way, would i use a missing link, or different MAF? on the civic i used oneway valves from a pet store so the MAP wouldnt read boost, worked flawless NO CEL!!!

ALRIGHT im rambling on, i was just looking for some DSM input on whether or not i can cut the manifold and get away with being a supercheapie.

ALL INPUT IS GREATLY APPRECIATED!

 

[VelocitàPaola]

You might be able to do it, but I doubt the resulting manifold would be very durable. SSAutochrome and similar manifolds aren't made well to begin with. Hacking one open and re-welding it won't improve any of its characteristics.

Keep re-reading that article you linked to in order to get a better semblance of what a basic turbo kit consists of. There are plenty of threads out there in addition to that article which cover all the components of 420A turbo kits.

 

[TommyV]

You might be able to do it, but I doubt the resulting manifold would be very durable. SSAutochrome and similar manifolds aren't made well to begin with. Hacking one open and re-welding it won't improve any of its characteristics.

Keep re-reading that article you linked to in order to get a better semblance of what a basic turbo kit consists of. There are plenty of threads out there in addition to that article which cover all the components of 420A turbo kits.

O RLY? I think i can get the manifold welded stronger if anything. but w/e...

and i know what a turbo kit consists of i'm just not sure how the MAF reacts to boost, was wondering what tricks people were using to prevent cel's and so forth. the wastgate has a 3-5 psi spring so not much boost at all. if i was to install this kit w/ 10.1 fmu and 3-5 spring would i throw a cel????

seriously w/ the kit i have and the dirt price for the car, around 500 dollars can be spent to boost. and thats bang for your buck.

 

[Locke]

O RLY? I think i can get the manifold welded stronger if anything. but w/e...

and i know what a turbo kit consists of i'm just not sure how the MAF reacts to boost, was wondering what tricks people were using to prevent cel's and so forth. the wastgate has a 3-5 psi spring so not much boost at all. if i was to install this kit w/ 10.1 fmu and 3-5 spring would i throw a cel????

seriously w/ the kit i have and the dirt price for the car, around 500 dollars can be spent to boost. and thats bang for your buck.

You definitely have a head start, with most of the turbo kit and a cheap vehicle.

It is good to see a new member do a little searching before posting. That doesn't happen very often.


To answer your questions;

The 420a powered 2g's (2gNT) don't have a MAF/MAS for air metering, rather a speed density system with a MAP and IAT sensor.

To prevent a CEL - and more importantly, fuel cut - we will employ either a Missing Link (ML) or a Fuel Cut Defender (FCD). The FCD is a solid-state active voltage clamp, usually adjustable, which prevents the positive manifold pressure signal from reaching the ECU. The missing link is similar to your check-valve idea, but tends to clog and not function correctly. The FCD is preferred around here. Try SymTech Laboratories: Design, consulting, prototyping, and manufacturing to get a good, inexpensive one.

You may be running lean - or on it's bleeding edge - with a 10:1 FMU. A 12:1 is the route we usually go when on the cheap, and with a Walbro 255HP (GSS342) will support to to around 8psi. Use the FMIC if you intend to boost over 5psi.

Of course, be sure the engine is in good repair before you subject it to boost. I am unsure about the Honda engines, but the 420a is an interference engine. If the timing belt were to break or jump more than a few teeth, the valves will collide with the pistons, usually causing considerable damage. If the timing belt hasn't been serviced in awhile, or you are unsure of when it was done, it would behove you to replace it, along with the tensioner and idlers.



There is quite a bit of information around here. Stick around and read up. If you have anymore questions that the search didn't answer, please ask away. Good luck, and welcome to DSMtuners.

 

[Blitzeclips]

O RLY? I think i can get the manifold welded stronger if anything. but w/e...

and i know what a turbo kit consists of i'm just not sure how the MAF reacts to boost, was wondering what tricks people were using to prevent cel's and so forth. the wastgate has a 3-5 psi spring so not much boost at all. if i was to install this kit w/ 10.1 fmu and 3-5 spring would i throw a cel????

seriously w/ the kit i have and the dirt price for the car, around 500 dollars can be spent to boost. and thats bang for your buck.

Making the manifold stronger won't make it perform better. But reliability wise it wouldn't hurt. I would st rongly recommend a leak down test and compression check before you even put another dollar into it. If the motor was subjected to alot of heat for long periods of time, or was abused at the time it could easily do some motor damge or atleast head damage. Hell it could even have a couple cracked pistons. So you would want to do those tests to insure the project's value.

Refrain from crush style pipes and cheap rubber hosing. It'll add up in the long run.

 

[RSTeclipse97]

I have been using the missing link for a little over a month now with no problems as of yet. I will probablly switch to the fcd for ease of mine but many have had great success with the ml, its totaly up to you.

 

[gsxtasy]

Why not just make that manifold.^^ With the proper flange for your turbo? It'd be cheap, and effective. Although if you could pull off what your saying, it would be too. Meh, good luck in any case, should be fun.

 

[MadScientist92]

Actually making the D series manifold mate to the 420A flange will be rather difficult. The ports on the exhaust probably don't line up. Which would mean alot of cutting and welding in which case unless you're doing it yourself will be as expensive as buying one. Here's a cast one off ebay I found real quick under 200 shipped.

eBay Motors: 95-99 eclipse 420a cast t3t4 t3 t4 turbo manifold (item 380008481987 end time Mar-26-08 12:14:55 PDT)

Also your piping will most likely have to be re worked. As far as the down pipe goes some minor modification is probably neccessary. If you're lucky it'll be just cut and extend. Because I'm pretty sure the 420A is taller than the D series motor.

But good luck. You're definetly off to a good start.

 

[4UH8ERS]

You may be running lean - or on it's bleeding edge - with a 10:1 FMU. A 12:1 is the route we usually go when on the cheap, and with a Walbro 255HP (GSS342) will support to to around 8psi.
.

This comment is the only one i disagree with here. Nothing against locke he's a mainframe of usefull info for these cars.

The simplest way to add the additional fuel required is with a FMU. An FMU is basically a second FPR(fuel pressure regulator) that is installed between the stock FPR and the return fuel line heading back to the tank. As boost pressure increases, the fuel pressure will increase above the set limit of the factory FPR at an increment determined by the size of the FMU you are using. FMUs generally are available in sizes ranging from 12:1, 10:1, 8:1, 7:1, 4:1, and 3:1. The most commonly suggested size FMU to use on our car when using the stock FPR and fuel injectors would be the 12:1 ratio unit (this isnt necessarily the best choice, read on). What this means is that for every 1 lb. of boost pressure, the fuel pressure will rise by 12psi above the static fuel pressure set by the stock regulator.

With the stock FPR factory set to roughly 55psi static pressure (0psi of boost present) and our system running at a maximum of 8psi of boost, that would top out our fuel system at:

55psi + (12 x 8lbs. of boost) = 151psi!! Yikes!

In reality, it generally doesnt reach this high of a level due to pressure losses from the stock fuel injectors having to be opened for such long durations and the fuel pressure limits of the fuel pump. Most people have seen good results with a maximum fuel pressure of around 105-110psi while running 8-9lbs. of boost on an otherwise stock setup. With that being said, why dont people use a 7:1 FMU instead?

55psi + (7 x 8lbs. of boost) = 111psi

This seems perfect so why does everyone suggest the 12:1 FMU? There are a few reasons why. The biggest reason is simply for extra insurance. Most FMU manufacturers will suggest this size because they honestly have no idea how efficiently your engine responds to forced induction and there are too many variables to consider with each customers turbo setup. All in all, this would be a safe choice to suggest to the general public. Its better to have too much fuel when running a turbo than it is to run too little. The problem with the 12:1 FMU is that it isnt really regulating the fuel pressure if you are running more than 5lbs. of boost, its simply closing off the return line to the fuel tank. With just about any aftermarket high pressure fuel pump, 100-110psi is the maximum fuel pressure it can deliver while still delivering any significant volume of fuel. Exceed this level and you are simply plugging the return line and reducing the volume of fuel being delivered, not to mention you are stressing the HECK out of your fuel pump!


The Proper Size FMU
Okay, this is going to be a bit lengthy because I am about to explain this more thoroughly than I have seen anyone else do, I apologize in advance. After talking for countless hours with FMU manufacturers and Turbo kit manufacturers for the non-turbo Ecipses/Talons, I have finally got down to the truth about what size FMU is correct for our application.

The great thing about our car is there has been quite a bit of research and development by major turbo kit companies, like Hahn Racecraft and Star Performance. Thanks to them, we have a general idea of how efficiently our engines respond to a turbo setup. Not only that, but we also have a target range to start with for our maximum fuel pressures. Granted, the size and efficiency of the turbo comes into play when fuel pressures are involved but most people decide to use a turbo that produces roughly the same CFM range as the turbos supplied in the Hahn and Star turbo kits. If you are going with a much larger turbo than they offer.... I sure hope you arent using this type of fuel system!

Back to the FMU situation. Like I mentioned earlier, at 8-9lbs. of boost on an otherwise stock engine you would want to achieve a maximum fuel pressure of roughly 105-110psi. This should provide a slightly rich fuel mixture, which is good to prevent detonation (also the number one killer of most turbo engines). When choosing an FMU you always want to aim a bit higher than your target fuel pressure. If running 8lbs. of boost you would try to achieve 110psi so lets figure out what size FMU we would need:

110psi - 55psi(maximum static fuel pressure of the stock FPR) = 55psi

So we need the fuel pressure to increase 55psi from 0lbs. of boost (static Fuel Pressure) to our maximum boost pressure of 8psi.

Now divide the difference by the maximum boost pressure.

55psi / 8lbs. of boost = 6.875

So you need to increase the fuel pressure by 6.875psi for every 1lb. of boost pressure. This is pretty darn close to a 7:1 ratio. Since each vehicle is different, there are always slight variances in the maximum fuel pressures seen. With that in mind, I would suggest the use of an 8:1 FMU when running 8-9lbs. of boost. This would give you a maximum fuel pressure of roughly:

55psi + (8 x 8lbs. of boost) = 119psi



Air Bleed Valve
Vortech Engineering: Air Bleed Valve

Vortech Engineering offers an air bleed valve HERE which you install inline with the vacuum source to the FMU which allows you reduce your maximum fuel pressure down a full 2:1 ratio. This will give you the ability to adjust your FMU range anywhere from 8:1 down to 6:1 so you can dial in your maximum fuel pressure for the best possible air/fuel ratio.

For people who think that this is too low of a ratio, just look at all of the users who run the Vortech S-FMU unit. The maximum ratio it is capable of is 7:1 and there are countless success stories of people who have used this setup for many, many years with the stock injectors. People have recommended the 12:1 FMU because that is what some tech support guy told their friend, who told their friend, who told their friend to use. Do you want the universal answer or the one that pertains to your car? Hmm?

For anyone choosing to run only 5-6lbs. of boost, thanks to Hahn Racecraft we know that a maximum fuel pressure of 85-90psi is generally needed. Using the calculations above we can see that wed need a FMU ratio of 5.83:1, roughly a 6:1 ratio. In this instance I recommend the 7:1 FMU with the use of the air bleed valve to dial in your maximum fuel pressure.

 

[Locke]

I'm just stating convention.

I see exactly what you are getting at here, and in no way disagree. For the sake of completeness, I'd be interested in seeing some flow calculations, or perhaps even wideband logs to back this up?

 

[4UH8ERS]

I'm just stating convention.

I see exactly what you are getting at here, and in no way disagree. For the sake of completeness, I'd be interested in seeing some flow calculations, or perhaps even wideband logs to back this up?

I tried to pull up some old 12:1 fmu wideband logs, but they are nowhere to be found. Then again i was using 235cc accells at the time, but they flow almost identical to stockers. 90% of my short lived turbo life was on portfueler. If anyone could get some logs prior to any tuning that would be great.

 

[RSTeclipse97]

I am running a vortech 10-1 right now with the stock injectors. My plugs look great and have no problems as long as i keep the boost at 10 psi or lower. At 15 - 18 psi i get fuel cut like mother, hense i oreder slightly larger injectors till i can afford a better set up. I know its not the best choice of things to do but if evrything is in tolarance and your careful its kinda ok.

 

[VelocitàPaola]

I am running a vortech 10-1 right now with the stock injectors. My plugs look great and have no problems as long as i keep the boost at 10 psi or lower. At 15 - 18 psi i get fuel cut like mother, hense i oreder slightly larger injectors till i can afford a better set up. I know its not the best choice of things to do but if evrything is in tolarance and your careful its kinda ok.

Whoa there... that's not fuel cut, that's just dangerously leaning out! I love experimentation and rigging things, but fuel systems are something I'd rather not mess with. Even with a 10:1 FMU, you're maxing out the pressure ratings on the fuel pump and FMU itself.

Jake, you made a valiant effort on shaking the 12:1 tradition, but the argument lacks a few key points. You mostly made mention of pressure and pressure ratios. The crux of the matter is that pressure by itself is virtually meaningless. You need to take into account flow ratings of the fuel lines, and most importantly, fuel injectors. Ideally their flow ratings are linearly proportional at different pressures, but, they're probably not.

To throw another kink into the works, you've assumed fuel pressure will infinitely rise to meet the perfect 12:1 ratio with boost pressure. Well, as most of us know, Walbro 255 HP's can't supply much more than 120psi, with the standard Walbro 255 dying at about 92psi, and the stocker barely reaching 80psi. Surely this effect somewhat simulates bleeding air pressure to the FMU.

The last unmentioned factor is injector PWM. I'm not sure what it is while the stock ECU is controlling the injectors, but it's still something to be considered and factored into the equations. S-FMU's can get away with larger injectors because they lower the base fuel pressure to mechanically match fuel flow even though injector PWM is the same. In turn, they can get away with lower ratio disks while in boost, because they have larger injectors! FMU's are just too different to compare the two.

Equations aside, there is an empirical way to test everything, obviously... but you guys hit the nail on the head earlier: we need wideband logs to test any theory.