6G Celicas Forums

NOTE: THIS IS FOR THE 5SFE MR2 MOTOR. I HAVE BEEN HANGING AROUND THE MR2 FORUMS FOR A WHILE AND THOUGHT THIS MIGHT BE HELPFUL.

source: http://www.mr2oc.com/showthread.php?s=&thr...30&pagenumber=1

The 5SFE motor in the Toyota MR2 makes about 100 bhp at the rear tires as delivered from the factory…plenty for a commuter car but lacking for horsepower junkies. Very few people in the USA have even seriously attempted to get more power from this engine which is surprising considering how many millions of Toyota Camrys, Celicas, Corollas, and MR2s there are out there on the roads here in the states.

The stock Toyota 5SFE motor has a bore of 87mm and a stroke of 91mm which means it can safely be revved to about 7,000 rpm before linear piston speed becomes critical even though the stock redline is about 6,400rpm. The stock motor’s cam timing and lift make the power peak around 5,000 rpm with peak torque in the 4,500 rpm range. Once again fine for a commuter car but lacking the real grunt I am looking for. The stock Compression ratio is about 9.5:1….low enough to run without complaint on 85 octane fuel. My car is a California model which mean in addition to the Exhaust Gas Recirculation (EGR) and Evaporative Emissions systems I have two catalysts on the exhaust system with the first being less than 12 direct inches from the exhaust valves….very poor for power production, very good for tight emissions standards. The Engine/Electronic Control Unit for the fuel injection is also specific to a California model car. All 5SFE motors also ventilate the crankcase through the inlet manifold which is far from ideal since most of the gas the being ventilated is previously burned blow bye that got past the stack of compression rings on each piston. Just like EGR, PCV gases will not add to the power production of the engine since they contain next to no oxygen or beneficially combustible hydrocarbons. The stock single throttle body has a 50-55mm throttle plate to feed all four cylinders through ridiculously long intake runners designed to benefit torque off the very bottom of the rev range. Most if not all Toyota 4 valve cylinder heads are either produced by Yamaha or at least partially engineered by Yamaha, a motorcycle company with an excellent history of producing very high specific outputs from very small displacement motors. My goal with this project is to make my Toyota commuter car motor into an automotive version of a Yamaha Sport bike power plant with no less bottom end than the stock car and way more power everywhere else.

With a goal like this all I am really doing is a backwards engineering project on the 5SFE. A typical Yamaha 4 cylinder sporting motorcycle has around 12:1 compression, 4 individual throttle bodies with bores of approximately 40mm each, a stainless steel header of either a 4:2:1 or 4:1 design, cams designed for the greatest benefit in the mid to upper third of the rpm range, next to no emission control equipment, ram air induction, a generous airbox with lots of volume to perform well across a broad range of conditions and a maximum linear piston speed of about 4,500 feet per minute.



This post has been edited by hioctane: Oct 5, 2004 - 1:16 AM

The stock exhaust system has now found it’s way into the rubbish bin along with it’s array of catalysts and its cast iron heft has been replaced with a stainless steel 4:1 header and mid pipe from a North Carolina Company called SSAutochrome. Their URL is www.ssautochrome.com. I give the URL only due to the fact that finding anything in the way of production performance parts for this car and this motor is nearly impossible, especially in the USA. I paid less than $300 for this item and it took only a few days to arrive at my shop which is what I consider great service! I like to support those who support the sport, and in this case these guys deserve a big plug. The header and mid pipe eliminated both of the catalysts on my California model MR2 and has oxygen sensor bungs for both the primary and sub o2 sensors. I have not been on the dyno yet as I have a lot more mods to do but this pipe really does feel as though it is making about 15-20 bhp more than the stock system. At the same time the new header dropped about 35 pounds off of the car and every pound lost can be felt when accelerating. It took about 5 hours to install in a fully equipped shop and was mated for now to the stock silencer/muffler that my MR2 came with. To compliment the header I switched out the California spec factory ECU for a 49 state model. The sound is very aggressive even through the stock muffler…raspy and rude. It will in time be replaced with a straight through silencer that should be quieter while offering a still greater increase on flow and reduction in back pressure.



Also high on my list of simple mods was to disable the stock EGR, PCV and EVAP emissions equipment since I do not want anything other than air and fuel going through my motor….since those are the only two things required to make good power. Disabling the EGR system is easy enough, just remove the vacuum actuator from the flow through valve and plug it off…without vacuum it will not allow flow of already burnt junk to enter the motor. I have since bought a set of block off plates to permanently disable the EGR and remove all of its cumbersome plumbing on my new motor. They are available through eBay and username: garagerevolution who sells them for about $20 a set for stainless steel block off plates. I added a crankcase breather filter from K&N and eliminated the hose that previously fed the throttle body crankcase gases. A similar step was taken to remove the California spec evaporative emissions canister and plumbing. Several of these steps will cause the check engine light to come on in the passenger cabin of the car…if this bothers you then you will need to source a factory shop manual and then find resistance values for all effected sensors and add resistors to make the cars ECU think all this junk is still on the car and functional. Since I will be replacing the entire stock ECU and inlet manifold I have not taken this step at this time. I have not noted any change in running characteristics or fuel economy on my car but others who have done similar mods have said the fuel economy will suffer a bit. Disabling the EGR has resulted in extremely light detonation at low rpm high gear low load conditions, all of this will be fixed when the new motor is installed and the new EMS (engine management system) is installed and tuned on the Mustang Dyno at CCS Tuning here in the Austin, Texas area. Their URL is www.ccstuning.com .

The camshafts in the 5SFE do not allow for torque to continue to build after 4,500 rpm due to short duration and small lift of the inlet and exhaust valves. When the new motor arrives the first items to come out of it are the camshafts. The will be sent to either Web Cams or TED components for a weld up and regrind procedure followed by heat treating to insure they are hardened to a spec equal to that of the stock camshafts. ON the 5SFE only the intake cam is driven by the timing belt with a sub gear on the intake cam driving the exhaust camshaft in an opposite direction. These timing gears are a helical cut variety with a silencer gear added to the exhaust cam to make the cam run quieter. I am after a bit of gear whine so I will be making the exhaust cam gears bind together by installing a special service tool designed to lock the gears in place. This should give a nice sound while doing nothing to effect performance either good or bad. The new cams will have a grind spec to allow for peak torque to occur at least 1,000 rpm higher than in the stock motor and for peak power to occur about 1,500 rpm higher. The new cams will also lift the valves about 2mm more than the stock cams did for superior cylinder filling at all rpms. Both the inlet an exhaust valves will be allowed to stay open for about 20-30 degrees longer than the stock cams allow for. This improves cylinder filling and effective compression and BMEP at elevated rpm. In the case of the 5SFE more duration and lift on the cams will make more power at all rpms than the stock cams allow for.

Headwork: the stock inlet and exhaust ports in the 5SFE are about the right size for the rpm range I am working with. My motor is retaining small but re-shaped ports...actually smaller than stock in a place or two. People get the idea that big ports are better because a flow bench (the simple kind) will always show that a bigger hole flows more air...but, the physics in play inside a motor are way more complex than a flow bench alone will lead you believe. I cannot tell you how many custom ported heads I have dyno tested on motorcycles that made less power than stock heads...but looked way cooler and had way better flow bench numbers! I will go to oversize valves since the stockers are coming out anyway. My goal with the head work is more based on air velocity than absolute flow numbers. I am using longer duration cams but do not want to loose low end power since this is a daily driver street car, the solution is to have as much valve area as possible and as much intake velocity as possible since the a high intake velocity will keep the trapping efficiency of the head as high as possible even at low rpm. The trapping efficiency is how much air actually gets trapped in the cylinder at the close of the intake event. Since the piston is rising and the inlet valves are still open the intake charge tends to back flow out of the combustion chamber…but if it is moving fast enough more of it will get trapped at all but the highest rpms. I will gladly trade few ponies up top for a few more on the bottom. Tuning is compromise and there will always be ways to get around small problems. The final piece of headwork is the milling or decking of the head to set the compression value to the desired spec. 10.5-11.0:1 sounds about right to me for 91-93 octane pump fuel. Track days will be run on leaded VP Racing Fuels Ultimate 4 which is 92.2 octane and about 7% oxygen by volume. This is usually worth about 6% gains in total power at all rpms. The head can have about 1mm of material removed by the milling machine. With this headwork and these cams, a timing belt failure will be catastrophic to the motor…but this is normal for high output engines.

Bottom End: The stock pistons in the 5SFE are cast units as opposed to the stronger forged units used in most high output 4 stroke motors. I am looking for suitable replacements that are of the forged variety. I will only use a slightly larger bore than stock since the bore centers are pretty close to maxed out as the motor comes from the factory. In my opinion the stock connecting rods are plenty strong and will not need to be replaced. I will make sure to the big end bearing clearances are correct and will replace as many of the bearings as needed.

The intake system: In the motorcycle world the only type of intake arrangements used on high output motors are the individual throttle body type with a throttle body for each cylinder. I have a set of used Honda CBR954 units made by Kehin and a set of Suzuki GSXR600 units made by the same company. One of those two sets will adapted to the 5SFE to complete the hard parts list. All I am doing for the proof of concept stage of this to saw apart a stock manifold, lathe up some spigot adapters weld them onto the butchered stock manifold and add the motorcycle throttle body set with the velocity stacks going directly into the trunk...this lets me get the straightest possible shot at the inlet valves for high velocity and makes changing the length of the stacks to suit different mods easier. I also have plenty of room to make a proper high volume resonant airbox in the trunk area and then use a Tom's style air scoop with a little custom glass and metal work to feed the airbox cool mildly pressurized ram air from the roof area of the passenger cabin. I have access to lathes, mills, CNC machines, plasma cutters and plenty of welders...this is the stuff I do all day every day just for little motorcycles and other folks. I have not done a truly personal project in years and this one is a lot of fun...and probably a waste of a lot of cash but it will run hard and sound awesome.

I can not think of any real disadvantage to using individual throttle bodies other than the time spent dialing it in and the need for a TB synch at every other oil change....which might take 10 minutes to do...no real disadvantage at all.

The problem I am trying to overcome with the individual TB's is the fact that with a single TB you will never get really great throttle response and high flow characteristics since the plenum needs to have a lot of volume to make good high rpm power and the "goodness" of throttle response is directly effected by the volume of air and the distance between the throttle plate(s) and the inlet valves. By going to ITB's you get a very small volume of air between the throttle plates and the inlet valves (excellent throttle response) and you can still have a huge (think about 10 liters) "plenum" or airbox which will resonate at high rpm adding torque to the top end of the power band without a sacrifice at the lower end. Almost all real high performance small displacement motors use a variation on this theme and I just think it is the way to go to get a good amount of friendly useable power from the little 5SFE motor.

Engine management: The stock Toyota EMS is crude to say the least with a bank/batch fire system that really only looks at a couple of parameters to determine optimum fueling. Many aftermarket companies like Motech, Accel and Megasquirt offer stand alone EMS’s that completely replace the stock injection system. Since the mods I have planned will come close to doubling the stock power output of the 5SFE I will have to go to a radically different system for introducing fuel and spark to my motor. Which system will it be? I am not yet sure since they all have advantages and disadvantages compared to each other and the price definitely plays a role in my decision making. My goal with this project is to make in excess of 170 bhp at the back tires…we shall see if I even get close as the months roll bye…oh and I want to do it for less than $3000 which is what the car cost on the first place.

No dyno yet?

nice, really amazing.

but i dont think hes gonna get 2x the stock power out of the 5sfe. theres just no way N/A. the guys really knowlegable though.

God i feel like a ricer for asking...but with what he was saying, crankcase beather, good or bad?
pros: why intake flithy air?
cons: light detonation at low load and rpm, check engine light, and wrose gas mileage. No large power increase reported.

Reviews

Almost a decade late bump, what ended up happening with this build?

Nothing. Nobody has had the balls to build a 170whp 5SFE yet. Most take the easy way out and swap a Beams or a 3SGTE (or a V6 nowadays) for easy power.

I guess if someone had more pride in the 5s, they would do it but in the end still lacking hp of just swapping in something else.

5sgte sounds like an awesome project to do. Would love to do that but restricted to emissions and having it as my DD car.

2015 bump

Did OP ever deliver? Has anyone else ever delivered?

I've got a few 5S' laying around and they are pretty cheap.. Ive been keen to pick up a new exhaust, get some high comp pistons from a Honda (H22A share the same bore - no idea if the wrist pin would fit the rods small end though - nothing a dremel cant fix..)

I have no idea but have you ever seen the k20 mr2 on YouTube... That thing screams!

Why spend all that money, for something that in the end wont deliver. Just because u want. Cool then. There are better engines right of the bat that you can swap

I own a 91 MkIII Turbo 5 SP Supra producing just under 375hp @ the wheels. It will get a lot more tweeks and upgrades but with all that power and Straight 6 torque, my 95 Celica 2Dr Hatchback is so much more fun to drive. It's not just the

Supras NADA value tipping 13K and climbing or the fact that the window for driving a car with a TRD 2" suspension drop on thawed roads free of rocks, build up of debris and has repaired potholes is about 2 weeks. Its that the Celica is nimble,

quick and precise. A 50 mph 90* turn in an intersection in the Supra means the rear end is free for at least 75 to 100 feet. With the Celica its a bit of under steer until you dump the cluch @ 65 dropping to 50 picking up the rear end and dropping

it inline with the new direction.

Now taking into consideration my 5sfe is attached to a gear ratio utilized to drastically increase the acceleration of this GT. (evident by 5th X 5500 rpm = 95 mph) and considering I have a Cali spec Celica in a climate that ground air temps are

under 50* 30% of the year and under 30* 60% of the year. My 5sfe will give an ECO-BOOST F150 a run for it's $ and that damn thing if you punch it cruising @ 65 will roast the tires.


So I say, I have come, I am stock and I will build. I'm starting in this post because the person who started it had done some great research and obviously knew what he was talking about. I am not looking to X2 the output of my Celica, yet if

ever. Goal # 1 add another 50 HP to the wheels

any help and support will be appreciated.

X2

considering so many options out there...

Not all of us have the equipment or cash to just swap a motor, paying for it would be ridiculously expensive.

Used Beams Red top $1350.00
Used Beams Rebuild $ ??? how hard has it been used?
Tech with tools and equipment $2000.00 - $3000.00
High performance parts $ ??? (haven't researched it)

I would be looking at $3000 - $4000 just to start and it doesn't guarantee a running car.

Sourceing parts, from reading forums, is one of the harder things about a JDM swap.

Start pricing out a 5S build and compare cost vs gains. As far as bang for the buck, a swap is definitely the way to go, no questions asks.

Ahh...the best thing about being 50 years old is that you don't have anything to prove anymore. No need to show off, no need to race, nothing to prove to anyone and I'm happy in my own skin. Got all of that out of my system years ago.
My '95 has a stock 5F and it's got plenty to get me where I want to go comfortably and with a bit of style. I've got no desire to raise eyebrows with "the law" and no need to risk the huge fines.
My Celica is plenty of car as it is. If it wasn't I'd buy something else
Here's an old man tip: enjoy what you have...it makes life SO much easier and enjoyable!

If you don't like what you have build it til it's what you want.