Dyno Numbers on my SE30

#1

Mine just dynoed at 143.5 today. How’s that compare?

#2

Not great. I expect the majority of people are in the 145 - 155 range. Rebuilt motors are probably 155 - 160 if done by an experienced engine builder.

#3

We need way more info than 143.5. I’m assuming this is a Dynojet. Was it SAE or STD corrected? What was the smoothing set to? How did your plot look? Did you get the dyno files? Air fuel ratio? Let’s see some dyno plots. Here is my thread:

http://www.spece30.com/forum/42-engine/55499-king-tuts-dyno-experience

#4

Email me the data so I can look at the A/F ratio. Engine management issues can be a big player. I’m supposed to look at Chris Tut’s data too. Given that your top end is fresh, I would have expected 149 or 150. 155 IMO requires everything to be perfect.
.020 over.
New plugs, air filter, perfect injectors.
Swapping some DME’s.

155-157 require, again IMO only, reducing the temp of the motor a little, and swapping out more DME’s to find one that is especially sweet.

158-159hp IMO is pretty rarified stuff for us. Not impossible, but the stars need to align.

One thing that I’ve learned in my adventures is that sweating over a couple hp is lunacy. A person would much more wisely spend their time perfecting suspension bushings, alignment and weight distro, then chasing 3-4hp.

The big enchilada is coaching. That’s the hot ticket for better lap times.

#5

I’m with ranger on the need to see the A/F plot. A motor with decent leak down and compression numbers and a good head should be capable of the low 150’s if everything else is right. I’d be pretty disappointed in a freshly built motor was making less than 150.

Numbers around 160 aren’t that hard to achieve with a race built motor, but on the track that extra 5hp or so makes a lot less difference than carrying 1mph more through a corner.

#6

I personally performed the dyno testing yesterday on Scott’s Spec E30 on a Dynojet 248, SAE correction, smoothing factor of 5 (per the NASA Time Trial dyno requirements, as the car will occasionally run in TT). I cut the dyno runs at 6000 rpm, as it seems that running this engine any higher will just result in a lot of noise and decreasing power, and I didn’t want to blow it up on the dyno.

Dyno runs were as follows (in order):

1 - 139.69 rwhp, 146.14 rwtq
2 - 140.26 rwhp, 148.34 rwtq
3 - 141.32 rwhp, 147.52 rwtq
4 - 142.05 rwhp, 146.98 rwtq
5 - 143.57 rwhp, 147.23 rwtq
6 - 143.48 rwhp, 146.48 rwtq

Power seemed to increase (albeit slightly) as the engine got hotter, although there are no aftermarket gauges in the car, so the actual temperature is just speculation. The first pull was made with the idiot gauge below 1/2 (call it 3/8), and the last pull was made with the idiot gauge above 1/2 (call it 5/8). All other pulls were made with the idiot gauge right around 1/2. Nothing ever puked out of the overflow, so it couldn’t have been too hot. A carpet fan was propped on top of 2 tires in front of the grill with the rear of the hood open about a foot, since this car has no cooling fan.

The A/F ratios look to be pretty lean, at 15:1 above 5500 rpm. I know exactly nothing about tuning a Bimmer ECU.

I’m not familiar with the engine work that has been done on this car to date, although I suspect that the head was freshened after the timing belt broke and the pistons made sweet love to the valves last season. I don’t believe that the bottom end was touched since it left the factory, though.

I attached a .pdf file of all 6 dyno runs, but I have separate .pdf files for each of the runs, as well as all .drf files. If anybody is interested, I can send them to you with Scott’s permission.

Mark

#7

You are going way lean above 5500 and that is most of the cause of the disappointing numbers. That could be a bad WOT switch in the TPS, fuel pressure/delivery problem (weak pump, clogged filter, bad FPR, or dirty injectors). There are other possibilities, but start with those.

#8

Thankfully we are not racing dynos!!! I have seen, on my local dyno, numbers from 150 for a bone stock junk yard motor, to 165 on completely built motors. All have been tuned with multiple AFMs and ECUs to get the best F/A mixture possible. Each car spent in excess of 2 hours on the dyno. That is the bad:

The good part of that is the F/A ratio is safe to run wide open for extended time such as at RA and RR. CB

#9

[quote=“MarkMc26” post=56076]I attached a .pdf file of all 6 dyno runs, but I have separate .pdf files for each of the runs, as well as all .drf files. If anybody is interested, I can send them to you with Scott’s permission.

Mark[/quote]

I didn’t think anybody in the lower TT classes needed to worry about providing dyno sheets. I would be interested in the .drf files please. I’m still waiting on Ranger’s as well. If anyone wants mine, I can e-mail them.

#10

As the car sits right now, it is legal for TTD based on the Spec E30-legal upgrades that were installed (whether many of them improve the car’s performance or not). However, it will certainly not be competitive in TTD, as it is better suited for TTE.

In any of the TTA-TTF classes, it is optional to submit 3 dyno runs and your car’s minimum weight to the National TT Director, and he will create a custom base re-class for the vehicle (see the TT rules for exact details). When adding up modification points with this method, the sections for Weight Reduction and Engine modifications are skipped. This might help this particular Spec E30 stay in TTE, since it appears to be a bit down on power. This is one of the reasons why we opted to put it on the dyno yesterday.

Mark

#11

Like Jim said, I think there is something wrong in Scott’s fuel system and it appears that the fuel pressure is dropping off above 5500 RPMS. Power should peak around 6000 RPMs whereas Soctt’s power has already dropped off considerably by then. This makes me think the fuel system just can’t provide enough fuel to keep up with engine demand above 5500 RPM. I would change the fuel filter and then trouble shoot the TPS, FPR then fuel pump (in this order). To confirm you are losing fuel pressure at high engine speeds, you will need to install a fuel pressure gauge (unless someone has a better idea).

I can drop a known good FPR in the mail if you need it Scott.

#12

[quote=“MarkMc26” post=56082]This might help this particular Spec E30 stay in TTE, since it appears to be a bit down on power. This is one of the reasons why we opted to put it on the dyno yesterday.

Mark[/quote]

I wouldn’t call that down on power. I will be submitting my form to you for the Sebring event hopefully and running TTE at 2760 lbs. Tell him to add a couple more cylinder heads and run TTE. :laugh:

#13

Holy crap, man, those friggin cylinder heads…lol…there isn’t any more room in the tire well for a third…

Not that this is official for our use, but a Spec E30 “somewhere” was given a base re-class with the following parameters:

2750 lbs @ 150 rwhp = TTF**
2750 lbs @ 158 rwhp = TTE

I suspect that a 2700 lb E30 making 145 rwhp would still start around TTF** or TTE, but I’m just speculating. Only Greg G. knows for sure.

Mark

#14

[quote=“FishMan” post=56084]Like Jim said, I think there is something wrong in Scott’s fuel system and it appears that the fuel pressure is dropping off above 5500 RPMS. Power should peak around 6000 RPMs whereas Soctt’s power has already dropped off considerably by then. This makes me think the fuel system just can’t provide enough fuel to keep up with engine demand above 5500 RPM. I would change the fuel filter and then trouble shoot the TPS, FPR then fuel pump (in this order). To confirm you are losing fuel pressure at high engine speeds, you will need to install a fuel pressure gauge (unless someone has a better idea).

I can drop a known good FPR in the mail if you need it Scott.[/quote]

I’m pretty sure that Scott replaced the fuel tank, both pumps, and (I would hope) the filter about a year ago, when the car first hit the track and would barely run a handful of laps. As it turned out, the gasoline that had been sitting in the tank for several years looked less like fuel and more like high-pulp orange juice. I’m not sure if he ever swapped the FPR or not, and I’m not sure if the injectors were ever cleaned. Scott would have to comment on this.

Mark

#15

When I got the car, it had been sitting. After a few laps, it barely ran due to fuel issues. Come to find out, the tank was rusty and nasty. So I replaced the tank with a new one, put in two new OEM fuel pumps, changed out the crossover tube, removed the fuel pulse regulator, and put in a new fuel filter. I never changed the injectors, and probably should have done that, given that rust colored gas was coming out the fuel filter.

Where is the best place to rebuild the injectors? Also, where would you hook up a fuel pressure gauge? Not sure there is a rail I can tap into. I’d probably just mount a manual gauge on the cowl somewhere, is there any special CCR on that install?

-Scott

#16

I like RC Engineering for injector cleaning and flow testing. The GCR and Spec E30 rules say nothing about fuel pressure gauges. I don’t think a fuel pressure gauge runs afoul of the rules.

#17

Another fuel system failure point is the charcoal canister/fuel tank vent system. Check all components of the system and that should include blowing compressed air into the tank vent hose under the rear seat and see if fuel/air comes out at the canister. If you draw a vacuum on the system, it cannot provide fuel to the motor. Chuck

#18

I sent my injectors to Injector-Rehab dot com.

Can’t say whether they are the best, but I couldn’t find anybody locally to rehab them. They supposedly did before and after flow tests and sent me printouts of the results. Of course, I have no way to verify the printouts are legit.

#19

I had my car on the dyno at VIR at the event in late March. I got similar numbers and the A/F was almost to 15:1. I am thinking about cleaning the injectors and checking the TPS. The fuel filter is new.

I have seen two opinions on this thread: 15 is too high or okay. Thoughts? If i choose to do nothing for now is my engine on the way to blowing up with the A/F so high? The dyno guy seemed worrried.

#20

Normal for the stock DME would be 14:1, which is fine on a street car. A race engine would benefit from a richer mixture, if for no other reason than to reduce head temperature and prolong valve life. You won’t blow up the engine at 15:1, but you could burn the valves.

If the A/F ratio was at 15:1 below 5000rpm and about 14:1 above 5500rpm, the AFM and/or DME would be my first suspects. There are other possibilities, depending on what the A/F ratio curve looked like. If you have that data availble, post it so we can see it.