Tdi FIP governer mod

[Gremlin]

Hi to all,

V8 petrol heads look away................ oily diesely bits here...................

Been reading a lot about bosch FIP ve pumps lately due to aquiring a golf gtd. Now these puppies run the same or similar FIP as the landy tdi versions but they rev in excess of 5000rpm, tweaked correctly they claim power outputs in excess of landy tdi numbers from a 1.9. Now i have also read that the vw boys are installing landy FIP to thier golfs to achive what they call an mTdi instead of the eTdi in mk4 golfs thus turning the electronic tdi into a manual tdi like a landy (fitting new engines in old golfs). Performance is really quick for a diesel, which leads me to the landy unit of 2.5ltrs, surely it can handle higher outputs, with appropiate tweaks.

Now my question, would it be worth messing with the FIP to turn the revs up on a landy, say another 1000-1400rpm?? i know the disco FIP has the governer set at a higher output than the defender FIP (which i have). The limiting factor will be the standard turbo unit i belive. Has anyone really messed with new ideas for the tdi?? As the vw boys are quite good at thier diesel tuning and seem to have found the right recipies for geting the most of thier diesels (darn quick!)

I know that longevity will be compromised, and i know a landy will never be a hot hatch, but just for the sake of discussions, i think the tdi landy engines still have a lot of potential hidden in them.

I am seriously considering the governer mod on my tdi! It just that there are to many unknowns, like, will the injectors flow enough??, will the turbo choke my effort?? Will the valves float after 4000rpm ??(i doubt it)

Anyway, food for thought i guess..............

G

[disco_al]

i think the limiting factor is going to be the engine design. the 300 tdi has it's roots back to the old n/a engines, and as such is quite an old design - overhead valve.

the vw boys have been producing ohc diesels, which as a basic rule are much more likely to be able to handle higher rpm's than our LR units.

[BogMonster]

As above ^^^ I suspect the engine architecture would go bang if you start increasing max revs by that much, and the noise would be epic

[Daan]

The engine wont like it, as stated before, but more importantly, there is little point. above 4000RPm, the time you give the mixture to burn is vey little, and the piston is at the bottom by the time the pressure has maxed, being of no use whatsoever. You might achieve 5000 RPM or more, but it wont give you much (if any) more power. Thats why on diesels, tuning is all about getting more fuel and air into it, rather than increasing revs as you would on a petrol.

In my humble opinion anyway....

Daan

[Gremlin]

Ok i understand that, so why do the vw's work so well?? they max out at 5250 no load, with tweaks they go up to 7000 then the FIP cannot keep up it seems.

G

[disco_al]

smaller capacity maybe? but surely the most power/torque on a diesel is developed below 3k usually, so what would be the point of having a diesel that revs to 7k?

[white90]

The lower revs of a diesel is down to the time to complete the cycle

no spark plugs to ignite the mixture so advancing the timing/longer duration cam and increased rev range

as per a petrol do not work,

As I have read elsewhere increasing the max revs of a TDI will result in Engine Demise

and no gains.

More Fuel in the Mix(Black smoke)and compressed Air(big turbo) is where the extra power will come from

but a TDI is an old design with Head gasket issues these being addressed engine longevity will suffer.

[Daan]

Ok i understand that, so why do the vw's work so well?? they max out at 5250 no load, with tweaks they go up to 7000 then the FIP cannot keep up it seems.

G

Have you got a powercurve? The fact it is achieving the RPM is not to say it is actually achieving much power.

Daan

[GBMUD]

My understanding here is limited...

Power (BHP) is a measure partly influenced by RPM, the higher the revs the more power you get. Torque is what you feel when you plant your foot and is not related to power, other than the power figure being derived from a sum including revs and torque.

So, a motorcycle engine may have very little torque (125lb/f?) but rev to 15000rpm and make 200BHP. Fast on a bike as they are light weight so need only very little torque but would be disappointing in a Landrover (A Tdi has only about 110BHP, 220lb/f) to start with. On the other hand, an lorry may have 350BHP from a 12l engine but only revs to 1500RPM and makes monster torque, hence the high power (BHP) output from low revs (the same speed as the bike engine will idle at!).

Making a Tdi rev higher will give more power but the torque will not increase and the car will not feel any more powerful - but you will be able to show your mates a more impressive dyno sheet.

Landrover engines are designed to offer high torque figures from lower RPM and to have very flat torque 'curve' - in other words, to make their maximum torque right across the rev range. This makes LRs good at towing, pulling away at low revs etc. I assume that, despite a higher power output, Golfs are better at going to Sainsbury's or to sales meetings in Swindon driving in the fast lane of the motorway and may leave something to be desired when connected to a mini-digger on a trailer on a 1 on 4. Horses for courses, and see the whole picture.

Chris

[white90]

This is where Derv engines Differ

they do not need to Rev high at all

they have a maximum rev limit due to the time needed to complete the combustion cycle.

bigger Cubic Capacity, Turbos and increase fuel volume is where the power is made.

[Ex Member]

We are talking about Mark 4 Golf/Bora engines here, right? They are overhead valve, and a very similar design to the 300TDI. Maximum engine speed in a diesel is based on flame speed. The VW engines run higher boost, which gives more air and fuel to burn in the same space. These modified cars run around 25 to 30 psi. With the right fueling, this allows power at higher speed. Keep in mind that the guys running these high boost and fueling need to upgrade a lot of the internals of the engine if they want them to last.

Unfortunately taking a 300TDI to 30 psi blows the head gasket, so you are limited to the lower engine speed. If someone made better con rods and better head bolts, it might be possible. Or just buy a TD5.......

[BogMonster]

Sorry but I still think 6000rpm on a 300Tdi would be a swift way to dismantle large fundamental internal bits of it onto the ground

[Ex Member]

Really the engine speed is not a problem. They are well designed. You just cannot keep getting power once the pistons reach the combustion speed.

[nicks90]

so how does a td5 manage 1000rpm more than a tdi if its down to flame speed?

[GBMUD]

so how does a td5 manage 1000rpm more than a tdi if its down to flame speed?

Better injection pattern and/or batter combustion chamber design?

Remember the Td5 was built from scratch rather than adapted from an engine first used in the 50s (40s?).

Chris

[disco_al]

....and the TD5 is OHC. I'm 99.9% sure that the vw engines are all ohc as well now, not many of the old OHV designs still left in use due to the fact that they cannot be tuned to run as well as an OHC for the newer emmissions limits. Obviously there are still some OHV V8's about.....

As for the TD5, as stated, i would go with the better injection system, better mixture controls and generally speaking better design.

[redneck]

OHC is cheaper to manufacture than OHV, rather than benefits with emissions etc.

The main concern with any motor manufacturer is cost not emissions or developing clever technology. When I worked for an engine development company they were working on VVT systems to reduce emissions, Maximum cost was $5 per unit, for a hydraulic controlled variable valve timing device????

As for more power out of a TDI Start with polishing rods deburring the block,dynamic balancing of the pistons, rods, crank, flywheel and damper, blueprint the head and build it with ARP bolts oversizing where possible. Then start playing with the turbo, intercooler and injection system.

But the very first thing to do with any engine upgrade is to decide how much power you want, then you can build the engine to suit. Making an engine powerful is easy, making it powerful and durable is not.

[BogMonster]

Naaaaah you don't wanna do it like that, just wind that big screw on the back of the pump in about six turns and it'll beat anything

[Ex Member]

We are talking about ones with the Bosch VE pump here. They stopped using these engines in 2003. Let's not confuse these engine with other newer VW engines. These are quite different.

The TD5 is common rail. This allows the combustion event to happen faster as the injection time is much shorter. At the high speeds the injection time also becomes important. The VW guys run much larger nozzles as well to help. Keep in mind that they are still only going to around 5000 rpm on the style of engine in question. I assume the limit is the injection time which is limited by the lowish pressure injection system.

On the OP, I really have never heard of anyone changing the electronic pump for a manual one. It seems a dumb thing to do. Low cost custom tuning is easily available. The electronic control allows control over fueling, timing and boost. It is a lot more flexible than with a mechanical only pump.

[will_warne]

OK, I think we need to ruin this argument with some science... Max revs on a diesel (nb not turbo diesel - the turbo will be a factor here) will be down to flame speed IF enough air and fuel can get into the engine. However, that isn't going to be a set rpm for all diesel engines. Essentially, the flame speed will be effected by the atomisation and spray pattern of the fuel - a good, fine spray will mean that it burns fast much like a spray of petrol burns far better than a puddle of it. Then, the maximum theoretical rpm will be decided by piston velocity - a short stroke engine will rev higher. This could well explain the higher max rpm that the VW engines achieve.

There's one last thing to consider: the turbo. This needs to be chosen to supply enough air for the desired power band and max bhp. A small turbo (as you find on a 200/300 tdi) will pick up fast and have minimal lag but it will drop off early. A larger turbo will be more laggy and come in at a higher rpm but will give more power. Therefore, if you want to make big power/revs out of a Tdi you will need a bigger turbo but you will loose out at lower rpm. To make up you could use a VNT turbo, a pair of differently sized turbos, hybrid super and turbocharging or a shot of nitrous to fill the void before the turbo spools up.... All of this assumes that the engine can be made to make the power. In the end you'll probably end up spending 'a lot of' thousand pounds on an engine that 'may' be strong enough and will only make OK outputs. If you want to increase the size of the powerband then ditch the diesel - there are some great engines out there that will give a genuine 6,000+ rpm powerband which is twice what you'll be looking at for a well build diesel....

[Aragorn]

One big reason they alter the governor on the GTD and other mechanical VW engines is the bosch VE used has a multistage governor.

This starts to activate around the middle of the rev range, 2-3krpm, and slowly increases to maximum governing at the 4000rpm limit. This means though, once you hit this point, its starting to pull fuel out, just when your really wanting maximum fuel. If you increase the max limit to 5000rpm, then you have more fuel available in the mid to upper range of the "normal" rev range, allowing the engine to produce more power. The mod isnt really intended to allow the engine to rev higher, as people have said your pushing the flame front, and also the cam profile just isnt designed to operate at those RPMs.

They usually remove one of the springs on the governor shaft (probably the softest one?) and replace it with something solid so it cant activate that stage of the governor. This stops it pulling fuel out of the mid range and as a side effect will allow a slightly higher max RPM, although its probably not worth using the extra revs.

If the landy tdi pump has the same multistage governor then removing the same spring should achieve the same result, just dont go revving it to 5k all the time, or you'll end up with some nice crankcase ventilation.

[Aragorn]

http://forums.vwvortex.com/zerothread?id=3107325

[Bush65]

I don't know anyone who has actually pushed the 300Tdi enough to find the strength limits, beyond the known head gasket weakness.

I suspect some comments regarding blowing the engine up are pure conjecture and not based on 1st hand experience.

Multi layer steel (MLS) gaskets are available, and with ARP studs (assuming they are available) to replace the head bolts should allow much more boost pressure before the head gasket has problems.

Then injection pump mods would be needed to get more fuel to utilise higher air flow and boost. I have no doubt the governor spring would be part of the needed IP mods (for reasons of de-fuelling given in Aragorn's post).

I haven't looked at the governor spring used in the VE pump fitted to the 300Tdi. Aragorn provided a link to a VW forum showing mods to a governor spring used in the VW tdi, but many VE IP's use a simple tension spring instead of the dual stage spring used with the VW's.

VW tdi governor spring:

Simple tension spring for governor:

If the 300Tdi IP governor uses the simple tension spring, Bosch part numbers for these governor springs are Bosch 1-464-650-XXX where XXX represents the rpm code.

Some Bosch rpm codes are:

-386 (2,800 rpm)

-366 (3,200 rpm)

-374 (3,800 rpm)

-354 (4,200 rpm)

There are other governor springs available (some on ebay) up to 5,000 rpm, but I don't know the Bosch rpm codes.

As far as the above debate on diesel engine rpm's, my 3.9 liter, 4 cylinder, Isuzu 4BD1T has 102mm bore and 118mm stroke. Stock max rpm is 3,600, but the governor (inline IP, not VE) has been adjusted to give 4,500 rpm. I know of some others with the Isuzu 4BD1T engine who reliably run them to a genuine 5,000 rpm.

So I can't see why a smaller diesel engine with the bore and stroke of the 300Tdi (90.47mm x 97mm), can't run to 5,000 rpm, given appropriate governor spring calibration to overcome de-fuelling at a lower rpm setting.

Edit:

The governor spring connects the lever that the accelerator cable is attached to, to a lever that controls IP fuel rate. When the accelerator is moved to increase engine speed, the spring pulls the lever to increase the fuel rate. As the engine speed increases, the governor fly weights pull back on the lever to reduce fuel and thereby controlling engine rpm. To get more torque at the higher rpm's the governor spring characteristics have to be changed to allow more fuel.