Tuning Runs like sh*te after decat and turbo swap

[iamfabss]

Hey guys

Newbie on the forum, from Madrid ATM with a 08' tjet 120 Sport.

I've recently swapped my turbo to a VL36 with a lighter billet performance comp wheel (stock vl36 size), APE rear silencer, gutted cat, and removed middle muffler.
Also added a secondary O2 sensor spacer to avoid DTCs. Have to do a remap yet deleting the cat.

The car runs like sh*te. Terrible lag, turbo threshold is like at 3500rpm, no torque, boost is of course within the stock map at High rom only and it's hella terrible to drive. Fuel consumption is also higher.

Anyone could help me here? Is it just the lack of a remap? Car ran great before doing all that job together. And I've just swapped the turbocharger's chra with the vl36 one (also it's comp housing) and reusing the exh housing.

Some pics are attached..also a picture of the vacuum hoses to the n75 solenoid.

Thanks in advance!

 

[iamfabss]

Anyone???

 

[SnuffRadu]

You definitely should get it remapped as the stock ECU does not know that you replaced the turbo with a slightly bigger one, and especially that you gutted the cat. Any updates?

 

[iamfabss]

Not yet mate. Was thinking about refit back another cat or stay illegal. Bought a Fiat Coupe and didn't have time and money to spend on the GPunto yet.
Will post right after remapping with or without cat anyway!

 

[SnuffRadu]

Not yet mate. Was thinking about refit back another cat or stay illegal. Bought a Fiat Coupe and didn't have time and money to spend on the GPunto yet.
Will post right after remapping with or without cat anyway!

I'm very curious as I have the same car with similar mods, but I've kept the cat. Mine did 183 hp and 296 N/m on 100 octane gas. Yours might even go to 190-195 hp.

 

[iamfabss]

I'm very curious as I have the same car with similar mods, but I've kept the cat. Mine did 183 hp and 296 N/m on 100 octane gas. Yours might even go to 190-195 hp.

I hope so. It'd be pretty fun and quick but for just +10bhp of difference between cat and non cat... I'd prefer to stay "legal" as you just because would avoid paying someone to get the ok at the MOT inspection.

 

[SnuffRadu]

I hope so. It'd be pretty fun and quick but for just +10bhp of difference between cat and non cat... I'd prefer to stay "legal" as you just because would avoid paying someone to get the ok at the MOT inspection.

Makes sense, that's the same reason I've kept the cat and made an exhaust that flows a bit better and sounds sporty without being loud and attracting attention.

Though, the only reason I would delete the cat, would be for a TD04 upgrade and 380cc injectors, good for 220 hp.

It's fast enough for me now to be honest .

 

[iamfabss]

Makes sense, that's the same reason I've kept the cat and made an exhaust that flows a bit better and sounds sporty without being loud and attracting attention.

Though, the only reason I would delete the cat, would be for a TD04 upgrade and 380cc injectors, good for 220 hp.

It's fast enough for me now to be honest .

I totally believe it's fast enough like you have it right now mate. The mhi td04 is not an option for me...my car is the daily one and such mods would get me into unreliability issues and also will value depreciation in the case I'd like to sell it (even tho not thinking about selling it in short-mid term).

 

[SnuffRadu]

I totally believe it's fast enough like you have it right now mate. The mhi td04 is not an option for me...my car is the daily one and such mods would get me into unreliability issues and also will value depreciation in the case I'd like to sell it (even tho not thinking about selling it in short-mid term).

The stock bottom end of the 1.4 T-Jet is good for about 250 hp and 300-350 N/m as far as I know. There are people that pushed over that limit, but I'm not sure that would be very reliable. High torque numbers become the issue really.

Also having over 200 hp and 300 N/m+ on the front axle means it would torque steer like crazy without a limited slip diff. 180-185 hp is quite the sweet spot for being fun to drive.

Get a cat and test if the car works ok with it, I think that's the main reason the car runs poorly. The lambda sensor might be giving weird readings to the ECU because of the gutted cat.