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.

[talkingcars]

As long as the bolts aren't rusted it is quick to swap a cat out (5 bolts and the lambda probe).

Having the near standard exhaust should provide the back pressure a NASP engine needs.

I wonder if the difference between this and Stamfords is down to who did the remap.

[Stephen]

Well mine is same spec as yours. Janspeed manifolds and sports cat. ITG induction and then stainless duplex back. Remap and cams is next on the cards to see what can be done. I recon il be close to the 200 aswell if not above with cams.

[dave23572]

Originally Posted by talkingcars

As long as the bolts aren't rusted it is quick to swap a cat out (5 bolts and the lambda probe).

Having the near standard exhaust should provide the back pressure a NASP engine needs.

I wonder if the difference between this and Stamfords is down to who did the remap.

Stamford has standard manifolds but a de-cat.
So I have better manifolds, but a more restrictive cat.
I suspect though the de-cat is probably worth more than Janspeed manifolds on a sports cat, That's why Stamford is about 4-5BHP higher than mine.

[ZS Phil]

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