Seams a lot of effort for how many extra ponies?
Hi Rich,Seams a lot of effort for how many extra ponies?
Hi Nick, getting very interesting now over this Jetex back box of mine lol. I did phone Jetex & as you rightly said they test there exhausts on stock cars to go with stock downpipes & cats etc. This is the only back box design they do for the 8L which is the same for the Mk 4 Golf v6 4motion & also the TT has the same way pipe goes in but just has two tail pipes either side going out. Must surely have same sort of internal principles from same manufacturer. Would like to see someone else with back box to compare.Has anyone looked at the Jetex 8l rear box and compared to the oem unit or brands that are proven to flow? The oem rear box is capable off 300hp+ with a decent effective setup. The jetex 8l box is unique and like no other 8l system on the market its going again the grain.
Under load is sounds like the santa pod jet car, a high pitch high velocity air flow sound the type of sound which is related to a collapsed silencer or blocked cat. Its as if the rear box is being filled up with the gasses and forcing the gas out under "pressure" not flowing out clean as if the rear box is a pressure vessel if you know what I mean?
The car did make the delta numbers but during tuning i could tell there was a more effort needed and the timing and egts where higher other setups which I relate to back pressure build up and poor flow. I am seeing this more with the 8p and cupra tfsi on higher power setups on hybrids same effect and same sounds from the rear boxes building up pressure. The fix was to move to a another rear box design which aids a better directional flow exit.
The simple experiment is to kick the rear box off while on the dyno and do back to back runs and logs, a method I have used 100s of times to gain data to resolve issues.
I would love to see the data jetex have in the 8l running stage2 or above power with this design rear box. But we must remember most manufactures will only test and develop on stock untuned engines not setups at the edge of there ve window.
I have ran the inline jetex systems on the Cupra R and they worked prefect and sounded correct not like a jet engine sound.
Cheers bud, looks nice. Wished I had made the long journey & got Pipewerx to do the lot now. You live & learn.Would be interesting to see that kind of layout that Jetex backbox has inside, i can't see it being designed specifically for gases to get in and out quickly tbh
Enjoy the remap bud!
Not posted a picture in ages so heres my set up
Hi Nick, So my peak boost at 1.5 bar is completely safe on my standard rods but any higher is not, is that what you mean? If so is that not a bit close for comfort? I'm a worry guts so humour me if I'm asking a silly question.@paul
How is 1.5bar going to have any effect on the stock intercoolers sub 3500rpm? stage1 stage1.5 stage2 boost in that area is not an issue at all limiting factor is the rods sub stage2 still the boost and torque limiting factor is rods. Stage2 with rods and stock smic can happy go over 340lbft with 1.75bar. (I have seen some come in with the stage1 boost at 1.7bar on stock rods.. cringe factor for me I am happy at 1.5bar peak on stock rods at any stage of tune)
The hold back is when trying to hold boost up the rpm range to a point which egt and ait can rocket the stage of tune is to manage this effect. The addition of a fmic on a k04 at stage2 is for manage the charge temps while trying to hold the boost higher in the rpm range. Stock fmics can be used fine with stage2 if the whole setup is perfect and effective. Rolling roads wont show this effectiveness as most cannot supply both cores with a decent amount of air into the cores. Its the same smic setup as we use on r32 turbo at 500hp.
Hi Rich,
We're in the middle of this great Jetex back box design debate lol. So when are you planning the remap? Would be very interested to see if you have the same issue or maybe mine has a defect in it.
HI Nick,@paul
Whooooooshhhhhhhhhhh Not a Roooooarrrrrrr lol
and egts wanting to go into oem protection on the 350rpm sec runs which I never see at stage2, so had to use a different fuel and boost strategy counter.
I could add move boost at the top end and power would not climbed just egts went even higher, opening the air box gained around 100mb across the top end but no gain in hp. Normally at this stage by opening the air box I can see 12-15hp delta at the top end from the extra 100mb.
Hi Tuffty,Ah... the 'jet engine' sound was not mentioned... this is a typical noise a restrictive system makes to be fair... this is the noise my Miltek started making when I did the last round of updates on my GT30 setup at 400ish hp...
the Jetex box is not very wide so suspect its chambered at the other end...
EGT's would be a tell... I used an OE back box when I first did my GT30 build and EGT's went through the roof...
<tuffty/>
Yes Bill,jet noise does'nt mean its a restriction... but the exit of the pipe is causing the noise, but it does'nt exclude a restrictive exit to also make a similar noise.
proof is dyno it with it on, remove the back box and repeat dyno. Facts then confirm reality from perception
Well I'd imagine if their back box on the S3 8l & Golf 4motion were the only ones restricting flow then they probably wouldn't want the hassle & expense.Only developed and tested on a stock software car answers a few questions. Are Jetex willing to develop a system at stage 2 power? I dont mind lending a hand if needed.
If 25% pressure reduction does equate to 25% flow and 25% power, yes.exactly how i would understand it karl.
so if a standard exhaust has seen 300bhp that jetex should be seeing 300 + 25% bhp
Definitive test... Remove back box and rerun on dyno... If power lifts then you can confirm suspicions
<tuffty/>
agreed!I reckon they should use your car, just to make an example.
Definitive test... Remove back box and rerun on dyno... If power lifts then you can confirm suspicions
<tuffty/>