MGF/TF 1.8 turbo manifold

[Rob Bell]

Hi guys,

Just an update - I have finally had some time to drop Dave Paris at Power-speed a line regarding the fabrication of a turbo manifold for the K-series 1.8T engine, using the jig that Markus made up for Cadde's F, using the BBR GTi manifold as a pattern that Mykle very kindly dropped off with me at Stoneleigh. You got to love the power of the MG community!

The good news is that Dave can certainly fabricate it. I'll be dropping off the manifold jig with him shortly (if I am allowed by the steering committee - aka the wife! - I'll drop it off Saturday morning).

Unfortunately I can't give a clear guide on costs yet, but if you are seriously interested in getting one of these manifolds, please do let me know: if there are going to be a number made, then the unit cost is likely to go down accordingly.

I am going to be ordering at least two (for myself and Roger Parker).

Oh, and because the engine I have didn't come with it's original GT2052 turbo, Dave is going to explore other turbo options with the ambition of putting together a conversion kit capable of making a little north of 200bhp for reasonable pennies It may be we'll end up using a relatively plentiful standard VAG turbo...

[webba]

If you change to a equal length manifold and K03 turbo would you not then need a completely new map from the Z and F Mems 3 map ?

[Rob Bell]

Yes - but I was planning on remapping anyway - so not a major problem IMO. I shall have a chat with Mark to see what we can do.

[webba]

would that not involve a whole rolling road session? it all seems a lot of work as the stock Z and F map produces 200bhp .I dont really get what you are trying to achive here, why go for a equal lenght manifold and a differnt turbo to get the same bhp a slower spool time for what apears to be a lot more money ?

[Rob Bell]

Hmmm.... Glad you asked

Price wise, there may not be such a huge difference between the log and equal length exhaust manifold, but until I have quotes for both I won't really know for sure. With respect to the perceived disadvantage of a tubular manifold you describe, I would be very interested to hear why you think that this is the case? I am coming from a NA back ground, and so in my mind, tuned length manifolds make more sense. Do you have data to the contrary?

Why a different turbo? Well, this is all in the air at the moment. As mentioned above, my 1.8 came bereft of its original GT2052 turbo. I therefore have the inconvenience of having to replace it. I could purchase a replacement GT2052, but VAG K03's are more common and relatively cheap. Also there may be dimensional differences that may offer advantages for the VAG unit, but I am still trying to get dimensional data to get a better idea.

But you raise a compelling point: why spend on a rolling road session and pay for Mark's time for a custom map when I could just get Mark to provide me with a standard 1.8T remap and get the 200bhp that is the target for this engine?

Frankly, this is a fair point well made. At this stage, absolutely nothing is set in stone. My original plan had been to go with the GT2052. I shall try and get all the figures together and go with the most cost effective option. If I were going for massive power, then another turbo and remap would make sense, but as I am not, and am looking at the most cost-effective, practical solution, then the GT2052 is very likely to be the route to go.

I shall let you know whether I go plan A (GT2052) or plan B (K03)!

[webba]

http://www.sr20forum.com/turbo/84358-eq ... ifold.html a good comparison between log and equal length manifolds .

http://honda-tech.com/forced-induction- ... s-3118041/

http://www.examiner.com/article/choosin ... t-ii-of-ii

[Rob Bell]

Great link, thanks. Loose a bit low down, but impressive gains towards the top end! On that particular Honda application a gain of over 50 bhp was seen!

If I had the time I'd be looking at having both made and trying them both out - engines can behave quite differently and unpredictably. Cam timing is another variable here... This is going to be an undiscovered country for me!

[Mykel]

Yep, interesting read, webba Also I think a cork-screw like manifold like this would indeed fit in the TF’s engine bay. Not that I think top end horsepower is what we are after, though, it’s more the low rev torque gain that is interesting.

Rob, I also had a quick look at the infamous auction site, and GT2052LS turbos show up from around £160. As you know we HAVE to use this one for emission class regulations.

But I am already pondering another mod: Use a 16 valve MEMS3 1.1 litre K-Series from a Rover 25 and fit a turbo to achieve 120-ish bhp. Mykel’s gone over the top, I hear people sigh, what would this be good for, just leave the standard lump in the car. Well, it’s all about downsizing, lower tax band, better mpg, different torque characteristics. But that’s far away in the future, as the later 1.1’s are rare as hen’s teeth it seems.

[Rob Bell]

Unfortunately/fortunately we can't change tax bands in the UK: we're stuck with whatever the car came out of the factory in. So bigger engines no worries. Small engine no advantage. Except for fuel efficiency of course.

The EXF had a 1.4 turbo - so this idea has some credence in MG history

[webba]

[quote="Mykel"]Yep, interesting read, webba Also I think a cork-screw like manifold like this would indeed fit in the TF’s engine bay. Not that I think top end horsepower is what we are after, though, it’s more the low rev torque gain that is interesting.

I completely agree I feel 200bhp is all you can reliably achieve whilst it still being financially worth while. @204bhp we are already exceeding the maximum specification for the Turbocharger ,injectors ,and gearbox so with that in mind bottom end and reliability gains are what I have targeted.

[webba]

If I had the time I'd be looking at having both made and trying them both out - engines can behave quite differently and unpredictably. Cam timing is another variable here... This is going to be an undiscovered country for me!

But you would be back into the country of programable ecu's, rolling roads and my biggest concern relabilty. I only know of one person who has done more than 20k miles on a k-turbo producing more than 210bhp

[Rob Bell]

Matt Parker? I think Matt has put on around 24k on his ZS 1.8T?

MEMS 3 is programmable - and around 210-220bhp does indeed seem reliable on these engines. I have no interest in taking things beyond this level because to do so would involve much more work. And expense of course.

The advantage of forced induction is that we can get this power without increasing the rpm limit

I suspect we are all reading from the same page chaps. The main point of discourse really concerns whether you want to optimise low end torque at the expense if top end power, or vice versa. The question is whether one can walk a right rope of compromise between the two and have a wrong reliable manifold....

[webba]

How many BHP does Matt Parker's ZS produce ? and do you know the aproxx engine spec ?

I spoke to Mark Stacy somtime ago about custom turbo maps and he said that he wasnt prepared to do me a custom turbo map and that he basicly had a some pre made maps and I could have one of them but he was unable to make a custom map . has that changed now ?

"The question is whether one can walk a right rope of compromise between the two and have a wrong reliable manifold...." I dont really get what you mean by this.

[Mykel]

I had also talked to Mark about the maps, and apparently he has the original maps (150 bhp R75 and 160 bhp MG ZT) plus at least another one he uses for the 75/ZT as a chip upgrade. This will give 200+ bhp and 270-ish Nm of torque. Which is a bit stiff for a PG1 gearbox, even the uprated ones won’t keep up with this amount of torque load for long, especially if a lot of drag race style driving is involved.

"The question is whether one can walk a right rope of compromise between the two and have a wrong reliable manifold...." I dont really get what you mean by this.

I’m also quite puzzled, but I guess that’s doctor’s orders in a way ...

[webba]

I also know that he has a supercharged map and a vvc turbo map but they are use at you own risk maps so he does not offer them to the public

[webba]

I believe Matt Parker has replaced at least 1 turbocharger during his 24k.

[Rob Bell]

I can't give full detail of Matt's conversion because I don't have them, but I believe it to be a standard engine, running around 4.5-5 bar fuel pressure through the MGF fuel rail using an after market fuel pressure regulator.

BHP wise, I gather it's running around 220bhp on an Emerald map.

Has Chris Johnson covered similar miles with his TF, Ady?

"The question is whether one can walk a right rope of compromise between the two and have a wrong reliable manifold...." I dont really get what you mean by this.

Hmm - nor do I. The moral of this story is not to write forum replies on your mobile phone with predictive text switched on!!!
Should have read: "The question is whether one can walk a right rope of compromise between the two and have a STRONG, reliable manifold...." - by which I mean a manifold that doesn't fracture along welds/ pipe bends/ joints.

Having dropped off the manifold with Andy @ Power-Speed on Saturday, the verbal quotes are for around £700-750 + VAT for a single unit, dropping to under (potentially) £600 for multiple units.

In a market where the engines cost in the region of £100, and the cars themselves around £300-400 I don't see there being a long queue forming for this. And remember, this is for the manifold only. The down pipe will be a useful amount of extra cash.

This is not going to be a cheap option which ever way we look at it. On the one hand we can re-use the original R75 turbo manifold, but modify the bulkhead and fuel tank. Not sure of the costs involved there - but if getting someone else to do it, likely a three-figure sum. This compared to a manifold plus down pipe - the final figure has the potential to get into four figures.

And that's before getting into charge coolers, charge coolant radiator, pipework, brackets, remap, transmission upgrades.

The pendulum feels as though it is swinging back towards supercharging and using the parts I already have.

Darn it.

At least I am in China next week - perhaps I'll look into picking up a cheap, locally manufactured turbo or two If I don't use it, at least I should be able to put it on eBay for a profit...

[Rob Bell]

PS I should point out that the intention for a tubular manifold is to prioritise short primary lengths (may need to be unequal lengths, but I'll trust Andy's experience here). The Honda conversion has rather long primary lengths, with the primary intent on high horse power for the track. For road use, the short primary solution is likely to offer the best compromise.

And there are of course log manifolds and "log manifolds". What one OEM makes is not necessarily the same as another.

Take this:



versus this:



Both can be referred to as a "log manifold" - but one imagines that the flow characteristics could not be more different.

I am not imagining anything along the lines of this:



... although one might imagine that the torque-limiting aspect of such a design might actually benefit drive train longevity!

[webba]

Chris did a little over 20k with no problems at all although I know that Matt has changed at least a turbocharger.

You are right it is nearly £200 for a custom matched down pipe. You can do a really cheap ZR conversion but to do a MGF properly it is never going to end up cheap for the reasons you stated +

I am staying with a log manifold (on this build) as what I am looking for is reliability and near seamless power but I do plan to get far more creative with my next project as I have a spare turbo engine, t25 turbo and charge cooler.

[Rob Bell]

Who are you getting to manufacture your manifold Ady?