I was hired by one of your members to tune tune a 2.4 20vt. I am very unfamiliar with this car but as with any engine it is merely an air pump that needs to be dialed in.

I want to give some history about myself and the job so anyone with knowledge can input any ideas of what might have happened or where I made a mistake.

First of all I am not new to tuning I have tuned so many different vehicles over the years.

I started tuning in 94 with distributers and carbs in the late 90's switched up to rom tuning mostly doing visual disassembly of chrysler,gm and ford in early 2000's have been installing and tuning Autronic and other standalone systems. My dyno room is a climate controlled room with a 22000 cfm fan as well as 65000 cfm of room and exhaust air removal so over heating is never a problem. We have 2 dyno's one Mustang MD250 as well as a brand new DynaPack AWD. We monitor all engine knock with a product called " the knock Box" Knock Box

On the first tune we noticed the 450cc injectors were running out of duty cycle at just over 5000 rpm so we pretty much aborted the tune right there. The car also developed a good amount of det at 14 degrees of timing which I thought was quite conservative at 1 bar of boost but lowered timing until we were at 8 degrees to remove any indications of knock.
This was not a sustained hold and set process it was hear onset of knock and back out. I was using the load bearing portion and merely bring the car to 5000 rpm and touch it into boost and listen for det then back off readjust and try again.
I set a revlimiter and the client and I took the car out for a drive and it was quite nice and very responsive except in low load areas there was a couple lean spots.

Client left the car with us we got bigger injectors and at the same time checked the plugs the iridiums which I am not very fond of had cracked most of the insulators ones that were not cracked were loose, at this point we changed out to a good set of copper 7's to do the next tune for the larger injectors.
Monitoring this very close looking at the plugs and listening for det (this time none at all) could see the plugs starting to crack the insulator again. We called NGK and found a race version of this plug that moves the insulator up farther out of the combustion chamber. Did a compression test ( not a leak down at this point) and found that number 1 was about 20lbs lower but the car ran great with no missing at all.
Finished the tune road tested the car all was good. Today client shows up and drives the car loves how it pulls we are heading back to the shop and after a minor pull the car dies on decell. We get it started up but it is running bad get it back to the shop and pull the plugs. Compression is as follows starting at 1

120-135-135-140-140-135

All the plugs have had the ground strap folded in. Now this is typically very bad in my experience.
We have not checked the timing belt but after straightening the electrodes out the car ran ok. I have included links to the dyno sheets and the timing sheet. The engine has not been tore down yet but I am hoping someone out there can shed a little light on the situation.

I personally have a couple theories but will leave those out at this time unless someone mentions them. Keep in mind this is a 2.4. I will also add this I was shown pictures of the piston and was quite concerned about a couple of the design features but once again I do not know this motor.

torque and boost dyno sheet

HP and Boost Dyno sheet

Torque HP dyno sheet

timing table

Just wanted to add this car was no higher in AFR than 10.8 at boost. My main reason for showing everything here is I am looking for answers from others who know this car.
We obviously have a problem if this is tune related I need to solve it before we go through this again. If it is motor issue it also needs to be solved. It is kind of humbling to say the least but I consider myself a student of the automobile and never too smart to learn something new.

Hi,

I am running the same engine with Motec M600 engine management.
Our fuel is some way better than yours from my understanding, so my experiences are on 98RON fuel.

The engine does not need a lot of advance to make decent power especially in 2.4 form. There is also a lot of backpressure generated with internally gated turbos on this engine so that will also affect the ignition used. In general 8 degrees is way way too much advance at higher load points, I think mine goes down as low as 3 degrees and on a previous setup it was even less than that and I'm running better fuel and an externally gated turbo.
My other comment on the map is that it looks way too arbitrary, there is very little stepped scaling by load point.

I would question the use of a 7 heat plug on any tuned modern higher compression turbo car? An 8 heat plug would be normal and the iridium plugs were 8s.


10.8:1 AFR means you are relying a lot on the cooling of the fuel to get more advance. I think you would be better off mapping it less rich and then adding in the extra fuel as a safety measure afterwards. To contrast usually one of the tuners here (PT)runs 11.3:1 and my car runs 12.1:1 (not that this is particularly adviseable unless you are fully closed loop). The temperature of fuel and the cooling effect of overfuelling is not measured anywhere so you have to allow for the worst case.

How did you arrive at the selected boost pressure? In general on 2.4s they stop making more power with more boost at quite low boost so it is normal practice (not just on these cars) to use slightly less boost than the boost at which peak power is made because the point where you are not getting more power is such because you are getting so much backpressure and heat generated that any extra boost is just heat. Again whilst that heat is not measured (unless you have EGT correction) you are relying on the EGTs always being the same for the same load which is why you have to dial in some safety

Where are you listening for det from?

I don't actually think the compression is a problem, it is more likely that because the end cylinders are the coolest they have cooled down most and because the pistons have contracted by different amounts based on their cool temps that you are getting the disparity on compression. have a look down the bore with an automotive endoscope - as long as it isn't scored it is probably ok.

Cheers
John

I listened for the det off of the intake manifold there was a very nicemounting point I believe between 2-3. I also added another sensor on the back of the intake manifold.
Boost was set at 1 bar as a nice starting point on a built engine my client advised that we could go as high as 1.8 but I thought it better to start down low.
Curious as to what boost you are running you car at when you are at 3 degrees as you can see by the boost map we are just touching into 16 psi then taperring down as I saw no further gains at anything above 5000rpm . These cars must have an incredibly efficient combustion chamber to run 3 degrees of timing at boost most would have flamed out by that time. Once again asking. I have a rule of thumb I always run richer if there are no issues then slowly lean out always safer than sorry. Can you add any information into all the plugs having the electrodes pushed close. Also have you ever verified with a timing light that you are actually running 3 degrees as I also have seen some engine management incremently retard or advance timing based on RPM. I know it is a MOTEC but still asking as 3 degrees seems very low to me. I would almost think that it would be killing the flame front at 3 degrees. However this motor is new to me. Also on that motor what was the compression? Sorry I am all over the place here but inlet heat was monitored. What boost did you find you amde peak power at and what turbo are you using?

Thanks for your input
Cam

pm me your email address and I will send you my current ignition map. Please do not try to use it as I will definitely be able to run more ignition than John and please do not distribute it.
I am running 1.5 bar boost = 22PSI approx. On my old setup with internal gating like Johns I made max power at just 1.2 bar boost - that was with a GT3076R more or less with a 0.70 A/R T04S compressor housing.

I think my compression ratio is higher than Johns btw. It is either higher by 0.2:1 or the same depending on what pistons he has in.

Intake manifold is probably the best place to listen so sounds ok from that perspective. Some tuners listen from the rocker cover at the right hand side of the engine where there is a mount point (next to no.5).

The plugs only close when they are overheating usually. I run the NGK iridium 8 heat plugs. The 7s are too hot for the application AFAIK. Usually gap down the plugs as well. The plugs will close up or fall apart if the heat gets too high in the chamber, probably not the combustion itself but the sustained heat in the combustion chamber during and after combustion (bearing in mind backpressure = hotter combustion chambers). Look at it this way though, it's better that it is the plug than the piston

Your info is much apreciated. I always do things slow and progress very slowly and carefully. I have to admit that I am still finding 3 degrees not very much at all but obviously you did this before. John also has a smaller hot side on his turbo. Judging by what you are saying the 16 psi was not too much. Also the exhaust back pressure is probably most of our issue. Thus the dramatic falling off at 5000rpm. This all makes sense to me. I havn't done a leak down yet. I am bothered why I did not hear any detonation but this is probably mainly to due to the backpressure issue the exhaust gasses were probably supressing the det. What you say about the plugs overheating is possible especially with extensive back pressure. Sounds like I may have to build a better header for this car and get rid of the internal gate. How about extensively porting the exhaust side and having the wheel clipped. I have done this a few times when exhaust was restricted but a fast spooling turbo was the goal with good success. Also NGk rates the iridiums as a 7.5 these other coppers are rated as a 7 but they are recessed quite abit from the combustion chamber. I also gapped them to .030".

Hi,

The plugs overheating would explain why all 5 bent over at the same time. I'm hoping that by the sounds of it I won't need a complete strip down.

John, should I source one of the existing 20VT tubular manifolds and modify it or fabricate one here? I think maybe it's best if we fabricate our own. We can add the external wastegate, EGT bung, use the correct diameter tube and possibly move the turbo forward and to the right to allow a easier bend for the exhaust. This would need a custom support bracket but the existing one is almost past it's limits anyway so that's not a huge problem.

John

John, I assume you have ported the standard manifold and matched it to the head? I would also consider going to a 0.86 hot side like Mavric as that will certainly loose some back pressure.

From what I have seen of the 2.4 engines on a standard manifold you will get a big camel hump torque curve. The only exception to this (not seen JohnS graphs apart from SRR) was with Barbz running a GT3076R 0.86 with a tubular manifold which kept the torque flat to redline. That said, it also reduced peak torque considerably but it was building power all the way.

I guess you need to weigh up the costs of doing all this and what your goal is. I would be inclined to go with the bigger housing first like Mavric and see what can be achieved by retarding the ignition like John has advised.

Yes the manifold was ported to matched to the head by Torque Italia who had both the head and manifold.

Changing the turbine housing is a relatively cheap option which I can do myself. Is Maveric's turbo internally wastegated as well?

John

Yes he's running a GT30 0.86 internal wastegate with the standard manifold. As John has suggested, Mark at Owen Developments runs it leaner at around 12 AFR but with retarded ignition. Mavric has fantastic midrange torque although it does drop off at 5500rpm it is still making 300lbs/ft at redline.

I would fabricate your own to be honest and would not bother with the 0.86 A/R internal wastegate turbine housing. I had back to back tests with both housings and there was not much in it - certainly not enough to justify the difference in spoolup.


The reason why the backpressure becomes so apparent is the distance from the exhaust valves to the turbo is quite small and the length of ports in the head on the exhaust side is very short as well as the manifold run being relatively quite short. The manifold is not a clean 5-1 arrangement and the primaries are greatly different lengths all of which contributes further to the limitations of the flow.

The next thing you may get is that you get close to the limit of the Walbro fuel pump. I hit the limit of that some way below 500BHP on my setup and I'm running the GSS342 which has the best lph rating at higher pressures. There are ways around that which don't involve an expensive external swirl pot setup. I'm sure your tuner will be familiar with these as it is a common problem not limited to coupes.

Care to expand a little more please John?

Yeah the most common way is to have two parallel pumps feeding instead of a single. That has one or two potential issues if you have no safeguards around fuelling, such as if one pump fails it may not be obvious there is a problem. The two pumps must be identical so would suggest buying two new pumps

The other way is to fit a Bosch 044 inline. So the pipe that goes out from the fuel tank goes down to the fuel filter on the OS under the rear 1/4. Somewhere along that you fit an external pump and that relieves the walbro of its load (related to both pressure and due to the piping)and so allows you to flow fuel up to the capacity of the 044. Only thing neither of those solves is if the swirl pot empties in the tank which can happen.

I know what you are saying John, but I still think it is worth a punt given the ease and cost involved. The gains may only be 15-30bhp but a couple of years ago that would have been highly significant When you came out with your 2.4 many moons ago it blew the coupe tuning scene apart. Even my own 2 litre exploits have made their mark over the last 3 years

Anyway, all I am saying is that John's current engine/turbo setup should be good for at least 420bhp+ with a 0.86 housing which would be really fantastic.

Symptoms would be?

Ross

Yeah I see your point

No fuel I would imagine?

melted piston worst case, a bit of det and an obvious pull back best case.

this is a real shame John

as for the guys @ Lightspeed, you are doing a great job of trying to work on a engine with next to no experience of it, i also have a 2.4 variant, in fact, in terms of spec, it's almost idential to Johns in canada.

I did supply him with a donor chip to get him underway, which on my coop ( actually to PT version when mapped only gave 384, but that was down to my variator being seized solid )....

Melting & cracking plugs is a worrying sign that perhaps something else is amiss, I assume the fuelling can match the engine ? have you also checked the coop fuel pressure reg at the fuel rail ? when barbz checked my 3.8 or whatever it is now, it didn't even work properly & just bunged in a standard 3.0 reg....

I was hoping to hear some big big power figures, I just plray the top end hasn't had any heat damage to it pal...you worked so hard to sort it...

best of luck keep me informed as I'm gonna embark on finishing mine soon ( haven't driven mine for over 2 months at least ! )

Taz

also on a "dumb" note to LS, you are attaching the knock sensor to the block side of the intake manifold & NOT the plenum, as there are 5 off rubber donuts, which would totally mask any DET could be a simple mistake....

soz if my comment is a schoolboy error.

Yes we checked the fuel pressure and it was good, about 2.8 bar at idle which went up strongly when under load.


We started with 450cc injectors but these were starting to max out at 5000 rpm so we fitted 630cc injectors and performed a remap.

I'm pretty sure we attached the knock sensor to the metal intake manifold not the plenum.



John

Thankyou all for all your comments and advice it is certainly being heeded and worked into the program. I did attach the knock sensors to the intake and also one to the plenum ( sometimes the plenum is very good at anokifying sounds) We will work through this one part at a time. I think first on the list is the exhaust.

Proposed plan of action...

I've been speaking to ATP Turbo and they can supply me with an external wastegated version of the housing for my turbo.

They can supply a T3 style housing in either .63 or .82 A/R. I think the .63 would be enough for now as I've read it's about the same as a .86 on a T25 housing. The outlet can either be a 4 bolt 2.5" or T31 v-band. I prefer the T31 v-band option as it's going to be easier to connect the exhaust to it using a v-band connector than using the 4 bolts especially as the bolt holes would be very close to a 3" pipe.

I'm going to fit a SPAL pusher fan between the radiator and intercooler which will give more room between the engine and the radiator for the manifold and turbo. It'll also look neater as I currently have one of those dual fan housings but only a single fan configurations.

I don't have A/C so this gives more flexibility in the manifold design. I'm thinking of moving the turbo forward and to the right a bit. This should make the first bend of the exhaust less severe. A custom turbo bracket would need making but this isn't a huge issue as the existing one hardly fits with this turbo anyway.

A more extreme option would be to rotate the turbo 90 degrees so the exhaust outlet faces backwards towards the engine!

Lightspeed make manifolds using mild steel and then ceramic coat them. I need to send them some pictures as to how other people have made them. We've yet to decide on the length of pipes and diameters but they will be equal length and have a T3 flange. Lightspeed talked about a EGT boss on each primary but that may not be possible due to the tight space we have and may have to simply have a single EGT on the collector.

Thoughts...

John

Hey john

I have just bought a manifold for mine, also with T3 flange
I am using a gt2871RS, with the ATP T31 housing you mentioned so I can use an EWG. The mechanic is having great problems, especially with the A/C, I think theres not much problem with the fans, but the A/C is killing him, I think he mentioned theres only 2mm clearance from the downpipe