Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

had my car mapped and wanted some thoughts.

General Tuning Discussion

Forum Posts



Tech Articles

Discuss all things tuning in this section. News, products, problems and results. 

= Resolved threads


Hi everyone. so i have had my car mapped by a pro tuner. and just wanted to some advise on what i could do to get more power down the line.

so the car is a ford sierra cosworth. the engine is fully built forged pistons and rods. bored to 2.1 double valve springs, bd14 camshafts. t35 hybrid turbocharger that should beable to run 30psi of boost and give upto 380bhp. 850cc injectors. 36-1 trigger set up link monsoon ecu. mac boost controller. compression ratio is 8.1. rs500 intercooler. 3 inch stainless exhaust.

the guy who tuned it managed to get 300bhp at the rear hubs and approx 340 - 350 at the flywheel. at 1.6 bar of boost. however he told me that the car was knock limited at this point. and he could get nomore power from the engine. i have attached the map so people can check it out. he said he couldnt run anymore boost as it was starting to knock. he was using plex. i just wanted to ask how could i produce more power then ? as even if i stuck a bigger turbo on if it cant run more boost then whats the answer. bar race fuel ? and thats not an option. the car is running on 99 octance shell Vpower. so any ideas ? thanks. and if i missed anything dont hesitate to ask. thanks.

Attached Files

Keep the combustion temperatures down. More efficient radiator, intercooler, etc. Have you tried colder spark plugs?

Of course higher octane race fuel is a lot less expensive for that one dyno run for bragging rights...

A well balanced compressor/turbine set can make a big difference, generally any turbo described as a hybrid won't be that(couldn't see wheel sizes in the first couple of google hits but just by eye the turbine looks too small for the compressor). As above cold plugs could help. The is a compromise between rich afrs, ignition power, combustion stabilty and boost/power which is fairly engine dependant too, is it running a lot of fuel?

Lots of little bits and pieces like ducting cold air to intake, sealing around heat exchangers, lower temp thermostats, decent oil cooling and even fitting a 3.5 or 4 inch dump pipe (your turbine may be limiting factor anyway) can add a few a few % each (either directly by increasing charge density with less turbo pumping effort and hence exhaust pumping loss/charge carry over or through more stable combustion conditions making it less knock limited) which compounds quickly.

I think the short answer is, especially with the low comp motor you would have heaps less exhaust carry over in the chamber with a better matched turbo.

So to add. It has a updated alloy radiator and intercooler. And it’s also running ngk iridium plugs that are colder. But not too cold. It’s not about bragging rights that’s not what I’m after. I just expected more from my setup. as people with the same turbo but on a stock engine with bigger injectors are getting 380 - 400. So I’m just a bit confused. I think maybe a gt35 turbo may be a better option for the future tho. But I would be very dissatisfied if it couldn’t do more than 1.6 bar of boost at that.

Also to note. Everything is brand new. Including the turbo.

Also to note. Everything is brand new. Including the turbo.

If those cams offer more overlap than standard it is likely that you could go backwards compared to a stock motor on the same turbo. If you build the motor to breathe the turbo has to match, guys with big extend ports or Bridgeport rotaries are running turbine minor diameters easily larger than factory turbine major diameters to obtain reasonable intake:exhaust pressure ratios. Given you have increased engine displacement as well it's the first place I would look, otherwise try more conservative cams if you prefer early pickup and want to stick with that turbo. Looks like a lot of guys running bigger intake and standard exhaust cam with that kind of turbo setup? If you are happy with the power you suggested it's probably the cheapest and easiest to put the original exhaust can back into in and try again.

Post a pic of the dyno sheet and a datalog of the associated run.

Unfortunately I don’t have a log of the run. I could ask the tuner to email it to me but not sure if he would be keen. But I do have the dyno print outs I have attached them.

Attached Files

You are knock limited to 1.6 Bar with that turbo. If you where to go bigger on the turbo go with a bigger hot-side and wheel for the current turbo, you may change the engine breathing dynamics enough to allow for more boost without being knock limited. A more efficient turbo would do the trick for you.

Why is race fuel not an option? if you're happy with your current hardware I'd look into fuels or additives to them at least


What are we calling a "T35 Hybrid" mate?

What is it exactly?

Hopefully you only have a BD14 inlet? Not an exhaust cam also?

Hi stu turbo technics t35 is a t34 turbo with a .55 exhaust housing and a 360 bearing and cut back blades.

And no I have bd14 in and ex. As that’s what I was advised. However after a lot of reading I will be sticking a standard exhaust cam back in there. And then I just need to know what’s the best degrees to run the 2 cams at.

And I don’t want to run race fuel cost and all that!!

The TT T35 are a good unit and will normally nudge up to the 370 mark ok but the rear housing is restrictive up there.

1.6bar boost is quite low for that unit though, it has more to give, so your big issue is certainly why its knocking so early?

The cams could well be the biggest issue. A YB gains a little after 6000 RPM with them, but loses a lot everywhere else.

Personally I woudnt change the factory exhaust cam until we are firmly into the 500 BHP area.

A single BD14 inlet is good dialled in at around 112.

Ok thanks. And keep the exhaust cam at 110 degrees ? I agree people are running the same turbo unit and marking 380 at 28psi. So I’m convinced the cam is the issue. It’s all really laggy low down. Which is also the cam. I think the inlet bd14 will be ok. Or is there. Better Choice again ? The spec is fully forged bottom end. 8.1 compression. Double valve springs. and the rest you pretty much know. However it does have hydraulic lifters in there also I wondered if solid lifters would be a better choice.

Lifters are fine to around 7400rpm. Your turbocharger is limiting revs before the hydraulics.

Get your tuner to play with cam timing on the dyno, its not really something you can get right from forum numbers. 110 is a great starting point and guarantees no interference.

Luckily the pistons I have have massive cutouts in them. So even with the 14s I can advance and retard 5 degrees each way with no interference. “I checked when setting up the cams.” Ok cool well 100% with the standard exhaust cam.

Not sure which dyno's you are comparing, but from what I've seen during the years on our dyno and through tuning multiple YB's, 350bhp @ 1.6bar is usually in that ballpark.

Depending on the rest of the setup, it may be 340bhp or sometimes just shy under 370bhp.

I also personally never have found the need to go over than 1.8bar constant boost pressure on similar YB setups. Usually you start going in circles with reducing too much timing to run that higher boost on pump gas (99 Shell or 100 OMV).

I've taken a quick glance at the map you posted and compared it to a similar setup I tuned about 2 years ago. You're ignition map is somewhat similar... in the vacuum area they're pretty much the same and also in boost it's not far off (about a degree or two).

What I'm trying to say (without knowing who your tuner is), I'd say he tried to get the best results possible with your setup.

One possibility that could be the culprit of your knock limitation though, might be the stock 4 tooth crank trigger. Going with a higher tooth count down there and a proper camshaft sync signal, almost always resulted in much finer control over the ignition timing (and therefore power delivery).

Another advise I'd give for a 400bhp turbo, is not going with a GT35 (or your T35), but rather a GT30.

Hi thanks for your reply I do agree about the turbo and have looked at a gt30 as an option. Also I am already running a 36-1 trigger system.

If you look it’s not making full boost until 5000rpm it should be sooner than this. However I’m pretty sure that’s the exhaust cam causing this. I will be putting a standard exhaust cam back in. And it should make peak boost around 3500 - 4000 rpm.

Sorry I must have missed your attachments of the dynorun. From the last jpeg though, it looks like you have 1.6bar at around 3800rpm, peak torque at around 4000rpm, so that seems to be reasonable with your combination.

As stu above says. It’s defiantly knocking too early. It shouldn’t det that early. So that’s what needs figuring out. I have a feeling it’s the exhaust cam.

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?