Scott's Rods 3" turbo back system

[fridayman Senior Member Find all posts View Profile Close fridayman]

I had a 3" Scott's Rods system fitted yesterday and I am very happy with the result. I went from a 2.5" system with stock dump pipe and the difference in performance is quite surprising. Out for a long drive today I found that I was constantly having to back off the throttle because I was 10kph over the speed limit using less throttle than before. I can't wait to wire in the EGT gauge and then plumb in the boost controller and boost gauge tomorrow. Hopefully this is going to solve my lack of go when towing the camper up big hills.

[matt150 Avid PP Poster! Find all posts View Profile Close matt150]

This s good news, I have been chatting with them about my 150.

I'm keen to hear how it sounds and how it performs, any pics of the pipes ?

[fridayman Senior Member Find all posts View Profile Close fridayman]

The exhaust guys fitted an EGT bung to the dump pipe for me, so all I had to do was run the wire through the firewall and mount it in the dash. I have it in place of the ashtray and will make it look a bit neater after our trip.



Fitting the Turbotech boost controller was a bit more of a challenge, only because the hose it taps into is very short and in a very difficult to reach place (behind the air intake against the right side of the engine). The controller is simplicity itself though. It uses a spring and ball valve to restrict any boost pressure from reaching the waste gate actuator until the boost level reaches the set level. I also fitted a boost gauge at the same time - I think this is a must do if you plan to push the boost up.



The controller comes with the boost set slightly higher than standard - mine is boosting around 12.5psi out the box. From what I've read I can go up to 14psi before the ecu goes into limp mode (I have not been able to verify this yet).

The boost is definitely coming on quicker now as well as slightly higher. I am using much less throttle everywhere, and it looks like mpg might be back to pre-winch/bullbar/storage/fridge/etc levels.

[fridayman Senior Member Find all posts View Profile Close fridayman]

This s good news, I have been chatting with them about my 150.

I'm keen to hear how it sounds and how it performs, any pics of the pipes ?

It is actually quieter than the 2.5" system (with muffler removed). Here are a couple of pics.

[t303 Senior Member Find all posts View Profile Close t303]

The controller comes with the boost set slightly higher than standard - mine is boosting around 12.5psi out the box. From what I've read I can go up to 14psi before the ecu goes into limp mode (I have not been able to verify this yet).

The boost is definitely coming on quicker now as well as slightly higher. I am using much less throttle everywhere, and it looks like mpg might be back to pre-winch/bullbar/storage/fridge/etc levels.

I suggest caution with the boost. I put in the same controller at 120K km and after less than an hour of playing at 14psi peak the head let go through to the waterjacket at the no2 exhaust valve. After replacing the head I limited the boost to 11psi, which is about 1.3psi over max stock. I have no desire to replace the head again. You will still get faster spool up.

[fridayman Senior Member Find all posts View Profile Close fridayman]

I suggest caution with the boost. I put in the same controller at 120K km and after less than an hour of playing at 14psi peak the head let go through to the waterjacket at the no2 exhaust valve. After replacing the head I limited the boost to 11psi, which is about 1.3psi over max stock. I have no desire to replace the head again. You will still get faster spool up.

Thanks for the word of warning. I am very cautious of cracking the head. I have already replaced/improved most of the cooling system, and learning from your experience I might wait until I can get it back to a dyno place to re-tune the Tunit box at the same time as upping the boost.

What other mods have you done? Do you have an EGT gauge fitted? And if so, did your EGT's go up just from upping the boost to 14psi?

[jayden Lurker Find all posts View Profile Close jayden]

done the 3inch scott's rods exhaust as well sounds awsome and power increase is good, just ordered a safari snorkle as well.

[t303 Senior Member Find all posts View Profile Close t303]

Thanks for the word of warning. I am very cautious of cracking the head. I have already replaced/improved most of the cooling system, and learning from your experience I might wait until I can get it back to a dyno place to re-tune the Tunit box at the same time as upping the boost.

What other mods have you done? Do you have an EGT gauge fitted? And if so, did your EGT's go up just from upping the boost to 14psi?

Dtronic chip, standard exhaust, safari snork, EGT (probe preturbo), boost contoller and gauge. I have read that cracked heads are a function of high EGTs and the effect is cuimulative on weakening the metal. With the present setup it is quite easy to ring the EGT alarm under load, so this, not the boost, is the limit. When the boot is planted the boost pegs at 11psi quickly, then the rpms wind up. I personally don't believe running 14psi would make a huge difference in the overall acceleration result because I believe you just hit the EGT limit faster and then have to back off anyway. I use 720C as the alarm point and get off it or change down a gear straight away. The only thing I could imagine would help me would be a freer flowing exhaust to use the extra boost for longer before EGT limit. I am looking at a new exhaust and look forward to a before/after comparison. Remember that your EGT limit will be somewhat lower with the probe being in the dump, the amount being a bit of a rubbery figure, but somewhere around 1-200C less. I use the extra grunt for towing the 1.5T camper trailer and it works just fine to win back a bit of performance.

[t303 Senior Member Find all posts View Profile Close t303]

Double post

[fridayman Senior Member Find all posts View Profile Close fridayman]

I'm not sure if higher boost necessarily leads to higher egt's. I suspect I might be running a little rich which would generate unnecessary heat. If I upped the boost a bit, it might use the extra fuel and run slightly cooler (for the same output). I could just have go and keep a close eye on the EGT's, or I could wait until I get a chance to have it dyno'd again. I would prefer the 2nd option, but I have itchy fingers...

[t303 Senior Member Find all posts View Profile Close t303]

As I understand it if you want more go you add more boost and the extra fuel as needs, which creates more heat that has to either go out the pipe or into the head. Happy to defer to the experts, but adding boost without fuel would mean that the engine becomes just an air pump, with the corresponding loss of efficiency? Compressing the intake air will always cause an increase in temp. Regardless, when you get the ratio right for full burn you are always going to end up with more heat. That amount will be the decided by how much burns in there and for how long and the safe limit is hard to predict. I still reckon that the limit will always be the EGT effect on the head, even a blown HG will still probably be precipitated by heat. My HG was perfect when removed even with the 14psi boost, so I agree that it is PROBABLY not the boost per se, but if you have the fuel in there to burn correctly, you WILL get the heat.

Oh yeah, one more thing: I know you think that the voices you hear have some great ideas, but trust me, resist the urge! I can guarantee they won't be contributing to your new cylinder head! ;-}

[fridayman Senior Member Find all posts View Profile Close fridayman]

The voices were driving me nuts... So I upped the boost to 14psi. What I am finding is that trying to maintain 100kph with the camper trailer, in overdrive, up hills, the temps are a bit higher than I like - around 550 upto 600, and on the odd occasion when I didn't pay attention soon enough, even 650 (at the dump pipe). However, in overdrive the turbo only seems to boost to about 10psi (sometimes 12). Then when it kicks down out of overdrive (or I take it out when I tow up a hill), it boosts up to 14psi, starts accelerating again (or stops losing momentum on big hills), and the temps actually start dropping, by as much as 30-50 degrees sometimes. If I'm not towing the camper temps are between 350-550 at 100kph, with similar boost levels. On normal brisk acceleration around town it will boost to 14psi, but temps seldom get to 500.

I've started a new head fund just in case though