Janspeed manifold fitted - surprising result

[dave23572]

Fairly bog standard ZS180, only performance mod is the ITG induction kit.
After ages of deliberation I finally bit bullet and got myself some Janspeed manifolds as the first of a planned list of mods. The idea being to do each mod one at a time to see which ones make most difference.

I also modified them by spending half a day with a Dremel to fettle down the lumpy interior welds to hopefully make it flow better.

So ITG done (a year ago) and now the manifolds have been fitted on their own. Cat-back to come later.
I was really looking forward to the results.

And the results?
I literally cannot tell the difference!
What a huge surprise and letdown after all that money and effort.

What could be the reason for this?
I've seen before/after DYNO graphs showing 10BHP or so with this mod.

[sneekyparrot]

Originally Posted by dave23572

Fairly bog standard ZS180, only performance mod is the ITG induction kit.
After ages of deliberation I finally bit bullet and got myself some Janspeed manifolds as the first of a planned list of mods. The idea being to do each mod one at a time to see which ones make most difference.

I also modified them by spending half a day with a Dremel to fettle down the lumpy interior welds to hopefully make it flow better.

So ITG done (a year ago) and now the manifolds have been fitted on their own. Cat-back to come later.
I was really looking forward to the results.

And the results?
I literally cannot tell the difference!
What a huge surprise and letdown after all that money and effort.

What could be the reason for this?
I've seen before/after DYNO graphs showing 10BHP or so with this mod.

whats the rest of the system?

in order to get the best from ITG and the mani's you have to have the whole system flowing. Stock system still in place then all you have done is given the motor a chance to flow more air and exhaust but restricted it further down the line.

there are benefits to what you have fitted, Drew has dyno sheets to prove it and i have had cars with various options fitted.
the car with the ITG / full decat janspeed system was so much eager to rev out than the car with a cold air / scorpion system but stock mani's

This is the prob with kv6, its so bloody expensive to get more out of.

but with what you have spent then either decat and backbox or sports cat / backbox as you will have to fit the cat back at mot time.

P.

[dave23572]

It should all work better once I've got a decent cat-back and maybe a sports cat, but I was really expecting to feel some improvement with the manis alone.

[Skillen]

Originally Posted by dave23572

It should all work better once I've got a decent cat-back and maybe a sports cat, but I was really expecting to feel some improvement with the manis alone.

My janspeed manifolds are being fitted at the garage at the moment but I have 2.5inch stainless decat and piper system and an ITG already on there so hopefully will see something there and be able to report more.
I also have a standard 180 to compare against.

I felt a difference with decat back though so maybe that's the bigger restriction?

[dave23572]

I'll be very interested to hear your results.

Originally Posted by Skillen

My janspeed manifolds are being fitted at the garage at the moment but I have 2.5inch stainless decat and piper system and an ITG already on there so hopefully will see something there and be able to report more.
I also have a standard 180 to compare against.

I felt a difference with decat back though so maybe that's the bigger restriction?

[stamford]

If fitting a decat and decent exhaust system I take it you'll be re-fitting the OE cat for MOTs? May pay to buy a sports cat from the off and it'll be ready for the MOT. As said a free flowing exhaust will release the difference, but give the ecu time to part learn the changes. Manis is one mod I have not done as the remap was cheaper for the near on same figures. Torque being the bigger improvement from the graphs I have seen.

[Dave MGT]

Your not going to notice a big diffenance just doing the manifolds with out a decat. Cat is still holding the flow back. Makes a lovely noise when you have a cat back on as well!

[dave23572]

From the OP:-

I thought I'd share the results of my further mods:-

To go with the Janspeed manifolds and ITG Maxogen, I've now added a Janspeed sports cat, Custom "Longlife" freeflowing cat-back exhaust and had it re-mapped.

The re-map and the custom exhaust were done at AmD Tuning in Thurrock (they run a BTCC car!).

Unfortunately the before and after dyno runs aren't 100% comparable being different dynos, but probably close enough.


Dyno results

Dyno run 1 ("Before") (ITG maxogen only)
Dyno: AtSpeed (Rayleigh, Essex)
179.7BHP
168.7lbft
Given the standard car was 175BHP, it would seem the ITG gave me about 5BHP.


Dyno run 2 (Added Janspeed manifolds, Janspeed sports cat, custom freeflow cat-back) (NOT re-mapped)
Dyno: AmD Tuning (Thurrock, Essex)
187BHP
172.4lbft
This seems to show that the manifolds, sports-cat and free flowing exhaust are worth about 7BHP, before re-map.


Dyno run 3 (As run2 (Re-mapped)
Dyno: AmD Tuning (Thurrock, Essex)
194.5BHP
179.5lbft
Proof that re-maps do work, Added around 8BHP

AmD say it may develop 1 or 2 more BHP as the ECU adapts further.


Conclusion
The increases were more or less what I expected.
To get more would have needed a de-cat I suspect.
I didn't go down that route as I wanted to stay legal and also I didn't go for a loud/big exhaust as I don't like that sort of thing. That's why I went for a custom exhaust, so I could spec it to be as quiet as possible with a fairly standard looking tailpipe.
It's still a little noisier than I would like but will be OK.

On the road
It does feel a bit more powerful on the road, from 3500 onwards. Not to the point where I could say it's transformed the car but a noticeable improvement.

Total cost for all parts (except the ITG which I fitted a year or so ago), fitting and re-map was around £1400.
Was it worth it?
All things considered I'd have to say probably no, but I've done it now so I may as well enjoy it.
It was an itch I'd wanted to scratch for years and now I have. If I hadn't it would have continued to bug me.

Tuning the KV6 is expensive for relatively small gains, but with the other mods I have, I now have a pretty nice 180. Looking forward to getting it on track in 2015 with my new trackday tyres.

I really wish someone had developed a much better plenum manifold, I suspect there could be good gains in that area.


Dyno graphs attached:-

[dsirrom]

Dave

That is a really very interesting and helpful summary - thanks for putting the time in to share your experiences.

I am surprised that with all that stuff you didn't get over 200bhp.

I confess that I would have bet good money that the ITG/sports cat/stainless exhaust/ manifolds/ remap combination would have broken the 200bhp mark, but only based on a guess so it is really helpful to see what actually happens in practice rather than theory.

For me, the interesting follow up question is what is the best comination of the mods you have done or are available (you did effectively ALL the regular things bar cams) that would give the best bang per buck.

For example, decat / exhaust / ITG without cams or remap or manifolds could maybe give say 10 to 12 bhp which for the relatively smaller cost might make sense for most people (accepting you haven't done the decat for the reasons noted).

Also - if you did go for a decat and then a further remap would it break the 200bhp mark?

There is an argument to say that if you are not fussed about the power plant being original, and have the funds available up front (in this case circa £1.4k), then paying someone to take out the KV6 (and selling it on to recoup some cash) and putting in a lightly breathed on and rebuilt T16 turbo motor would give you the same (circa 197) or more (possibly up to 210 ish with a bigger down pipe and exhaust / cold air filter set up) power for similar or less money.

I accept though that for many people this is a step too far, in terms of either the initial outlay all in one go (which lets face it is hard to justify for cars worth on average less than £2k) or the potential risk in trusting a garage / tuner to do the work without any hassle or problems and that for others there is the issue of wanting to keep the KV6 for it's characteristics and 'authenticity' etc. If you are chasing power though then financially it seems to be potentially a cost effective option in the longer run?

Nice to hear you have got your car where you want it to be - enjoy the track days and don't forget to do something about the brakes

Regards
Dave

[ZS Phil]

awesome post... have some rep!