Back to back injector testing on the dyno

Had a moment to sneak on the dyno for an hour and half tonight to test some prototype injectors. Car definitely needs a bigger turbo and a retune haha. This is still on the 11mm tune, car has a 12mm now.

Here's what we have;

R520's, no nos


R520's, .050" nos jet


Prototype nozzles, no nos


Prototype nozzles .050" jet


Prototype nozzles , .057" nos jet


These prototype nozzles are 5 hole .260's. I'll let the respective vendor comment on them and answer any questions about them.

All runs were done at iq of ~3. It's still smoking like hell with nos but I didn't want to push anymore in without a reduced timing tune. It was starting to get rattley with the .057" jet.

Drives very similarly to the r520's on the road, definitely a bit smoother in midrange but has alot more diesel clatter from 1000 to 1500 rpm. Doesn't seem to affect anything though, just sounds like a vp44 cummins haha.

I'll have a better idea of smoke tomorrow in the daylight.


Now back to work in the shop!

Were both sets of nozzles set at the same pressures and checked for post adjustment flows?

Variations of just 10 bar can make a big difference in flow characteristics.

It would be like comparing one nozzle with an IQ set at 8.0 to another set at an IQ 0f 3.0 and claiming one outperforms the other...its THAT big of a difference!

On the R520 race injectors there are no less than 10 different flow ranges that can be set, where were these set?

The same holds true for the other nozzles. If both are set identicaly then you would have a valid comparison with the same tune, same engine and conditions.

Drivbiwire said:

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its obviously a scam..................

although i do see the possibility for there to be variables there

there are definitely variables, but I don't think it would make more than a few hp difference on the dyno, especially if it's repeatable...

If set correctly you can make a Race 520 flow the same as a Sprint 520...there is a HUGE margin for variables with large hole nozzles.

Nozzles are not a fixed flow, it depends on how you set them up. This is why we offer varied flow rates for all nozzle versions. We can turn them down or turn them up (to a point). The difference can be 50hp+ at the extreme end of the spectrum.

Ben Dur said:

its obviously a scam..................

although i do see the possibility for there to be variables there

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Scam? No simple question, somebody has to know where they are set post the data.

Ideally, both would be set identically to eliminate the variables. You already have the same car, same tune, same day...now the injectors become the deciding factor.

If you guys want I'd be happy to set them for you (our tolerances are less than 1 bar variation at max pressure), just cover the shipping and I'll throw in the balancing and fine tuning. I'd like to see how these stack up.

you might be able to get R520's to flow as little as Sprints, but you defnintely will NOT make Sprints flow anywhere near what R520's will flow when you simply swap the R520 nozzles onto stock bodies without messing with anything.. if you take 2 sets of unaltered new bodies (like t4's for example) and put a different set of nozzles on each set of bodies for testing, they won't be that far off from each other.. they absolutely won't fall into any extreme differences relating to how they are set up.. most of the difference will be the nozzles.. I'd be interested in doing comparisons before and after you had your way with them just to see if power delivery is any different.. if it is as big of a difference as you say it is, it won't all have to be done on the same day with exactly the same weather conditions, etc.. You could just do it on the same car and same dyno with no changes to the car as long as the temperature is close..

The secondary pressure will be all over the place assuming they have never been set. I will see a variance of 30-40 bar. Pilot will generally be close within 5-10 bar.

I can document the before and after pressures to show the baseline data.

Seriously if you guys want them balanced out let me know, it would be interesting to see how they perform.

If you guys get them to me by Tuesday I'll have them both back to you on Wednesday of next week.

secondary pressure doesn't has that much of a influence on peak power, altough at low rpm's it becomes feelable.. everyone who is shimming the first stage towards 250-260bar will end up with close to 400bar secondary if you don't unshim the secondary spring.. it's a good thing altough, if you have small nozzles with a 12mm head I thik they might stay open during the injection instead of chattering, and I think shimming them up might minimize this effect up to certain extend, altough this is just specualtion as I cannot look inside the cylinder to see whats going on..

Why do all these dynos show a dip in power between 3500-4000 RPM? And why is the torque peak at 3000 RPM? Seems kind of high.

Good question Peter. What is the rest of the set up? Turbo, engine internals, etc.?

there is only a dip in torque in the runs that included Nitrous.

the dip in power is simply an effect of the formula used to calculate power, and the fact that the torque peaks and gradually falls off.

the runs without nitrous look exactly as they should more or less.

IndigoBlueWagon said:

Why do all these dynos show a dip in power between 3500-4000 RPM? And why is the torque peak at 3000 RPM? Seems kind of high.

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Yeah, I'm sure some software tweaks in the 3200-4000 range would help get that torque from dropping so much. The torque peaks at 3k because it has a big turbo IIRC. And, this dyno is just odd lol.

whitbread is most likely running a huge turbo on the car, i agree.

on all of the nitrous runs you can see that the power, and torque suddenly drop off at about 4500 rpm

im wondering if this is a stock tuned car with some big bolt ons, or what...

I'm betting money if he is running nos shots it's loudspl's car and if that is the case pretty sure it is an 1856 turbo IIRC haha

Keebler145 said:

I'm betting money if he is running nos shots it's loudspl's car and if that is the case pretty sure it is an 1856 turbo IIRC haha

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yep it's not a huge turbo at all

stock CR w/ ASVs

it really needs a larger turbo and reduced CR

Tell me about the numbers. Are they corrected? And if you're running that small a turbo, why is the torque peak both low and late? 164/273 with R520s and an 12mm (or an 11mm for that matter) is pretty low. You should be well over 300. But I don't know how to interpret the numbers, not familiar with that dyno. So set me straight if I'm off base.

Superflow will usually give lower numbers....it's the eddy-current type, not inertia like Dynojet

Had similar numbers w/11mm setup before + VNT 20

This is the link to the old runs, different tuners (Kerma + Rocketchip), 11mm setup....

http://forums.tdiclub.com/showthread.php?t=271475&highlight=smokey+fun

new tune should give better numbers

So how do folks think the superflow compares to a dyno dynamics?

And the dynos in the link don't have the dip at 3500 like the ones here. But the numbers are pretty low, even compared to dyno dynamics runs, especially the torque figures.

Different turbos....VNT 20 then vs. 1856 now. Not sure what's causing the dip.
Yes, numbers seem low w/ current setup

Superflow is the preferred dyno for nitrous cars to give more accurate numbers...less spiking from nitrous activation. It's water-braked I believe..

The dip to me looks like a fueling problem. I had the same type of curve when my case pressure relief valve had popped on my pump.

hopefully no issue w/ the IP....it was just built by Giles

maybe a problem with the lift pump?

Maybe, hadn't thought of that. But didn't someone run dyno runs recently with the lift pump connected and disconnected?

I'd show Giles the data and see what he says. I guess it could also be a boost spike and recovery, but it doesn't seem that dramatic. Perhaps a first step is to re-tune for the 12mm.

Regardless of the dip the charts don't do the car justice. Those #'s by no mean reflect the performance of that car. I can't believe how much a 12mm pump woke that thing up. My car with similar compressor wheel can't even touch that car (granted his larger nozzles and pump put him on a new level all together). I think the car has a lot faster spool thanks to the smaller turbine but I agree it does seem like the power comes on late.... maybe he is spinning the tires on the roller

Keebler, have you dyno'd your car? It would be interesting to see how the numbers differ if you feel they're so much different to drive.

It would be interesting to see 1856 vs. 2256 vs. 2260 on some of the builds coming out of Matt's shop on the same dyno, same day.

2256 w/ similar air + fuel mods should be more whp

lol....I wish it was smoking them on the rollers but that's not likely

The car needs a retune badly, I'm sure that's why the torque curves differ so much from the previous 11mm setup. I'm also going to get a reduced timing tune for heavy NOS use on the dyno. I'll try to get it back on on tuesday with the software updates.

And as Farfromovin said, this dyno reads funny/low. There's a dynojet right next to this superflow I like to use and I'm told the exact same car will dyno about 15-20% higher on the dynojet than the superflow. Problem is that the dynojet doesn't have a optical tach hookup so you only get hp over mph and then have to convert by hand if you want tq. It's also shocked (=inflated numbers) much easier by nos/turbos since it isn't braked.

Hey Pete, unless you're offering to pay for dyno time, setup multiple sets of injectors, ship them for free, and then retest them for free, I'll respectfully ask you to please refrain from bringing the mood down. We all know there's going to be variables and we have to reach a compromise somewhere since our resources aren't unlimited. Both sets of injectors tested were set up by a very reputable vendor so he'll have to answer what the exact setups were as I don't know.

FWIW, here's the same car, same night as the graphs above dyno'd at iq of ~9 with the prototype .260's. No other changes, just lots of heat soak haha.

Tolerances of (+/-)15 bar of error for a trigger pressure is a BIG difference in fueling at this extreme end of the spectrum.

I can promise a max deviation of .5 bar CERTIFIED and .25% total error at 1600bar with 10ms sample rates, I only use certified ISO spec calibration fluids to futher eliminate the error and simulate the injection events perfectly, this will allow a true nozzle to nozzle comparison.

And YES I am offering FREE of charge the balancing and FedEx overnight shipping back to you guys. The dyno, well thats up to you guys.

Just get them to me. I'm curious to see the side by side dyno comparison when set up properly.

Based on what I am seeing in those plots the error on those injectors is really throwing of the performance.

I know from experience that when these are set to the tolerances we are capable of, ALL injectors should peform smoothly up and beyond 4000 rpm. Milisecond differences and less than 1 bar tolerances are very real factors when pushing power out to this level.

Like I said, free of charge, then you guys can tune off of that with minimal variables.

I'll also let you guys know how much they were off for this last test, and where they are set at for the next run.

Don't change the tune yet, leave it or have another one ready...don't change too many things at once.

Matt, I will kick in some money here to see this happen.

Plus I'd also like to hear drivbiwire's comments/opinions of how well these prototypes "set up" when compared to a typical Bosio product.

My motives are because I'm still a little torn on which direction to go with my nozzles choices for my car.

hmm.. DBW is offering what seems like a sweet deal especially if you're planning on dynoing them back to back anyway..