SVT engine performance-Solutions!

[athens7]

Looking for dyno charts of SVT Zetecs, with or without camshaft upgrades. While trying to solve a problem concerning engine cut off above 3000 rpm when the clutch is depressed, I took the car to Tom Lesperance at Focus-Power in N Belmont, NC. He put the car on his chassis dyno. The first run yielded 129 hp, and had to be aborted at 6000 rpm because the air/fuel ratio was 15:1, and the exhaust gas temperature was 1500 degrees, causing us to fear for the safety of the engine. 9 hours and 25 dyno runs later, with a custom PCM tune, vct eliminator, and adjustable cam gears, the engine put out 147 hp. There is also a good size "hole" in the torque curve between 2700-3700 rpms. As a stock SVT motor puts out 170 hp at the flywheel, and Caterham USA and the Caterham dealer represent that the Kent camshafts will increase hp by 20, my motor's performance seems wholly inadequate. SO:

What is a typical percentage for hp drive train loss?

Why is my motor down 25 hp from a stock SVT when it should be up 20?

How do I eliminate the torque curve hole?

Why would the stock PCM allow the car to run so lean?

Before I spend yet more money chasing this problem, I sure would like to see some other dyno charts for comparison.

Attached are my chart, and a chart from Caterham USA purporting to show what the SVT motor should run like, with and without the cam upgrade. Any insights are appreciated.http://www.usa7s.com/aspnetforum/upload/1802166355_small chart.jpg

[slngsht]

15% to 20% loss is generally quoted...

 

As an example, my LS1 was rated at 345 hp from the factory, and puts down 291 hp at the wheel in my vette, which is about 14% loss. same engine in my rotus only put out 278 to the wheel, partially because of the tune (changed exhaust without retune), and also due to greater losses from a higher numerical ratio rear (the higher the ratio, the greater the loss).

 

Since your dyno place specializes in Focus, what does he have to say about how your numbers compare to his other customers? He must have 10s of those runs...

 

Can't help you with the dip. I'm assuming after his tuning, that the spark and a/f raio in the 3000 range are now good, right?

 

Can you actually feel that dip? or could it be due to the way he is loading the car down?

[drew...]

Were you hooked up to the OBDII when the runs were made? Did it flash any codes?

 

Are both the variable cam timing and variable length intake manifold activating correctly? (For both their main effect is to raise the torque curve at lower RPM's)

[Al N.]

Not SVT, but here is a thread with my Zetec chart with Focus 12 cams and ITBs...the entire thread is worth reading as people chime in with input on rwhp vs. crank hp, etc.

 

Al N's Superlight on the Dyno

 

 

[slngsht]

Al, looks like you also got exactly 148 hp also. It's interesting that your run starts at around 3K RPM, so if there is a dip, it wouldn't show on your chart. at 4K, you both have about 80 hp - very close.

[Kitcat]

Manufacturer's horsepower claims are right up there with diet claims ("Lose 30 pounds in the next week!). The dyno is merciless in exposing the puffery.

 

For the record, I would kill to have 148 rwhp. As the dyno showed on my "135 hp" Crossflow recently, I was putting out 93 hp. Where did the other 42 hp go? Maybe it never existed, except in the advertising claims of Caterham.

 

BTW: what did 9 hours and 25 dyno runs cost, if you don't mind my prying (I paid $500 for a dyno tune up of my carburated Crossflow 3 weeks ago)?

[WestTexasS2K]

When I got my motor dynoed NA in factory form it made 186hp. It is factory rated at 240hp. So that is about a23% loss. With a little tuning we got it to 198hp. But other guys have had the same tuning done and have gotten at much as 215 out of thier cars. So dynos and dyno operators vary by at least 10% from what I can tell. After supercharging our car we were making 296hp but other guys on the S2KI forum were reporting as hight as 320-340 range for the exact same set up. So I think it is a combination of tune, the engines themselves. Although all built in the same place with the same parts some just run better than others due to suttle differences. Type of dyno used/ gearing etc.

 

Manufacture claims on hp gains rarely come to be reality. So the stock engine should be 170 minus 20% is 136. The cams look like they added about 11 hp at the wheels. So the cams added about 14 more at the crank which is where the manufacturer makes their claims.

[athens7]

Mazda, I am assuming the mapping is optimized. That said, I am going to a 2nd dyno shop next month, also with a dynojet, for a 2nd opinion. Part of my tune from Focus-Power was a Predator PCM programmer that also functions as a data logger, so I'm going to hook it up and put some miles on the car. Any specific data that would help with diagnosis? Yes, I can feel the dip, when I hit the throttle at 3000 rpm in any gear, the car does not pull strongly until 4000 rpm, then acceleration is much stronger.

 

Drew, yes we were hooked up to the OBDII port, and no codes, other than a PATS code that may be related to the hard starting (immobilizer?) and/or the lack of a key on power signal (the Caterham wiring harness doesn't include that connection, apparently). The VCT was operating correctly, but now it is locked out. The DSI (dual stage intake) is functioning properly, and has been adjusted to switch at 6100 rpm, up from 5100, as this was the spot where power increased, instead of dropping off.

 

WT2K, assuming 20% loss, 146.6 hp at the wheels equals 183 hp at the flywheel. This is AFTER a custom tune, and locking out the vct. Using the numbers on the engine as supplied by Caterham, 129.3 hp=162 hp; not even up to the original Ford factory number of 170 hp, let alone the 200 hp number I was quoted.

 

Al, do you have a Zetec Supersport? Was it supplied by Caterham, and with any mods other than as listed on their website?

 

Kitcat, Tom charges $450 for a full custom tune, plus $375 for the Predator PCM programmer (you keep the Predator, which retains the original factory map, and Tom will give you a copy of the tune he makes for you).

 

Regarding the accuracy of factory hp claims, Ford's experience with late '90s Cobras indicates that traditional manufacturers have a responsibilty to be reasonably accurate, and are actionable if they aren't. Why should Caterham be any different? I paid a lot more for my car than a new Mustang! All of Caterham USA's promotional material represents this motor at 185 hp, 200 with the cams. Is it unreasonable of me to expect that to be correct, at least within some appropriate variance (10%?)? Several people have told me they believe the Caterham chart is actually for a Duratec 2.3, not a Zetec 2.0.

 

Some of the Focus people with whom I've spoken say the SVT can bog down at lower rpms, and that the SVT's vct is designed to compensate. My cams would likely exacerbate this tendency, locking out the vct adding insult to injury. The graph shows the dip is less pronounced in the original form.

 

So:

Why is my car down, in Caterham supplied trim, 10 hp from stock when it should be up some percentage of 20 hp?

Why does the dip exist? I've seen only one dyno chart with a similar dip, and it was corrected with cam timing, which Tom says he was unable to do on my car, even after multiple attempts.

What responsibilty do the sellers have to help me resolve this problem?

My plan is to data log some, then get a 2nd dyno run. If no solution is apparent, the next step would seem to be to return the car to stock SVT specs in all regards (cams, programming, vct), then test. It should be at least the same as a stock Focus SVT, if there is nothing wrong with the motor. This will get expensive!

 

 

[Kitcat]

Athens7:

 

Maybe the dyno reads low? Everything I have read about these devices suggests that they are wonderful at establishing a baseline hp # and then serving as a tool to optimize that # thru careful tuning. Which you did to good effect.

 

They are less useful at establishing an accurate horsepower number.

 

How does the car do in the real world? Is it fast? Take it to a drag strip and get some #'s. Maybe it's the dyno that's off.

[athens7]

Next dyno run Tuesday the 13th. Different shop, also with a Dynojet dynomometer. I think having a 2nd set of numbers will be useful to both verify the curves, and check power. If the 1st dyno was off, or the tune leaves something to be desired, it may become evident here. As to the accuracy of the hp readings, even if they are inaccurate on a specific car, they should be accurate relatively between similar drive lines. Focus-Power had a number of charts for SVT Zetec engines, which with Tom's PCM tunes were putting out 145 hp at the wheels, basically the same as mine WITH the hot cams. The only question remaining there is whether the transverse fwd drive train or the longitudinal rwd drive train has greater power train loss. I emailed Caterham UK asking about any info they had on drive train loss percentages, but I haven't heard back from them. I did have a compression test and cylinder leak down test performed, to check whether an internal problem was at fault, but compression was 13 bar +/- 1/2 bar (182 psi) on each cylinder, spot on for a 10.2:1 compression ratio, and leak down was only 3-4%-good news!

[JBH]

Brad:

 

Where are you going for the next dyno?

 

The good news is your compression and leakdown tests are solid. Then you have to start going through the list of things that cause HP losses: insufficient fuel delivery, timing, air flow, exhaust flow, etc.

 

What was the A/F ratio after all the tuning. I was thinking about going to Focus-Power to tune my Zetec Supersport (like Al's) because I am quite certain I am not getting a full 170 rwhp. I may just dyno it locally to see where I am at, but I am a little afraid to see the numbers.

 

Why couldn't Tom set the cam timing?

 

What gear was selected to run the dyno?

[Kitcat]

Any updates/progress?

[S1Steve]

Brad,

I went out to the garage and dug out my dyno sheets, I would post them if I could get this new &^#@% HP printer to work. My 7 has a stock Zetec, Web-con FI, cam timing gears, Superformance header, nothing else.

First Dyno Run- Max Power- 128.9 Max Air/ Fuel-17.5

 

Second, Well dyno sheet says 35th, Max Power=139.2 Max Air/Fuel=17.5

Maybe JohnK will get into this tuning post, He tuned my car out in Ohio,and is very sharp with this subject . I will get him on the phone and maybe he can post a reply. We have been there !!!

 

Steve Novelli

[athens7]

2nd dyno run at Balanced Performance in Buford, GA. Nice shop, lots of fast Japanese stuff (GTR with 1200 hp!). 1st run was 148.4 hp, 1.8 hp off last run at Focus-Power. 2nd run was without the K&N filter. 4th run was without the exhaust , from the flange back, to check for restrictions. The numbers would seem to indicate Tom's assessment of the car's performance was accurate. Ed Senf (the tuner at BPM) said our drive trains should have about 15% loss on the dyno, so I'm putting out about 174 crank hp. He agrees with Tom that this number is too low, considering a stock SVT does 170, plus, the cat is getting too hot, and the air/fuel is still too lean (red line on the bottom of the chart). Tom had set the air/fuel target at 12.9:1. The exhaust, and the PCM programming, appear not to be causal factors, however, we will probably go back to VCT on the intake, as the low end drive ability should improve. Ed looked at the factory PCM settings, and indicated that the SVT seems to have a volumetric efficiency issue between 2800-3500 rpm that Ford compensated for with ignition and valve timing. It seems the hot cams exacerbate this weakness at the low end, and locking out the VCT makes it even more pronounced. The question now is, what's the cause for the power drop? If it's not an internal engine problem (which appears unlikely), it's either the cams, or air or fuel delivery. I don't have any check engine lights on, other than the usual ones which Cody at Caterham says are normal. The cold hard start is gone, as are the PATS immobilizer codes, but the car has a hard hot start issue. I wonder if the hard start, and the lean a/f ratio are related (note the a/f at idle). Ed says he thinks the car is gasping for air, and one of my mechanics wonders if Cosworth already maxed the airflow through the head, and the hot cams are just reducing dynamic compression by keeping the valves open too long. Cody continues to maintain that the cams up the power, and will do so without PCM mods, so I wonder if something else is causing the problem (TPS, air intake, etc., etc.). Ed is researching head flow rates, and some other things. I expect we will return the engine to it's pre-NC state (stock PCM tune, VCT), and re test. If the hp drops back to 135 range, we will remove the cams, go full SVT stock, and test to make sure the stock motor makes 170 hp. Nothing like throwing $$$$ at a problem to make it go away (hopefully!).

 

Steve, I'd love to see your dyno runs. The a/f seems very high at 17.5 max; where in the power band does this occur?

 

JBH, Tom spent hours timing the cams, he just couldn't flatten the low end dip. Ed says he feels Tom's tune was solid, but this problem goes beyond tuning. I will probably keep the adjustable exhaust cam gear on the car, so that the exhaust cam can be timed, even with the intake VCT. All runs were in 3rd, because Ed said the Dynojet's resistance is high enough that 4th gear runs don't work as well. He said the power loss would be minimal in 3rd as opposed to 4th. http://www.usa7s.com/aspnetforum/upload/1027191495_Nov 13 2007 chart.jpg

[JohnK]

Brad,

I've worked with a number of Zetec engines and several different engine management systems. I used a (self) modified Dynojet for the work.

The first rule is to toss any considerations of max HP and torque out the window. If all you're after is top end power, take up drag racing, and use a carburettor and distributor. The only reason to use a computer controlled engine management system is to give you great drivability - which is mid range torgue. While Dynojet has an attachment that allows tuning in this realm to be done, I've never run across a shop using one. A good start would be to find a shop that uses a Mustang or similar "load bearing" dyno. Then ask them if they can do mid-range tuning. If they say something like "Well, we do full-throttle pulls", look for another shop.

I could not follow what your engine management setup is. Basically there are two kinds Table driven (speed density or alpa) and Ford. Table driven systems work only for a given engine configuration - if you take a brand new Camero or Honda or whatever, and put on a K&N air filter, it will run worse because the Table was not programmed for that air flow. Ford systems are adaptive and will actually adjust to changes in the engine configuration as long as you don't touch the set of sensors that came with the stock engine and you don't change the configuration too much. All of the after-market EMSs that I know of are Table driven (Pectel, Webcon, Edelbrock, ...) Some outfits sell chips that plug into the diagnostic port on the back of the Ford ECM and alter the behaviour of the ECM. These work (I have heard) pretty well, IF you've got EXACTLY the engine configuration that the add-on chip was programmed for

If you can find someone that understands how to tune an electronic ECM such as a Pectel and has the dyno to do it, you can get superb performance. I'll guess that, if you drove S1Steve's ho-hum stock Zetec you'd be sick to your stomach at how well it performs.

I, personally, have seen no examples of shops so far that I think know how to tune an engine - they are out there. Rousch(?sp) knows how, Calloway knows how, ... but none of us can afford these shops. The reason for this is that it takes a ton time, a bunch of equipment, a well-developed protocol and a pretty enormous foundation of knowledge and understanding to develop a calibration (a tune) for an engine.

The last Zetec I did, and I've developed tunes for three Zetec engine configurations where I had to start from scratch, turned out pretty well. It took me over 30 hours just getting things "in range." I stopped because the weekend was over and I lost access to the shop. The owner was an old guy with years of dirt-track racing and engine building experience. He took the car out for a bit in the area's twisties and came back with a big smile on his face. He paid me and left, and never even mentioned the dyno sheet or asked about how much power his engine was making.

I consider myself a real light-weight in the tuning area, but because I'm a scientist, I understand the fundamentals and the tuning process, and have been able to develop some pretty reasonable calibrations. However, from what I've seen and IMHO, other than the big guys, there don't seem to be any shops out there with dynos that know what they're doing when it comes to electronic EMSs. If the shop is doing runs and looking at the dyno sheets to see what's happening, they don't know what they're doing. If they're looking at fuel curves and completely ignoring the torque curves, and keeping an eye on the knock sensor, then they know what they're doing. If you don't have detailed access to adjusting fuel delivery, you can't develop a tune. Spark is where you get your power, but that's more difficult and more complicated.

 

Well, I did it again. Every time I read something like this or that someone's bought a wide-band A/F sensor and is planning on getting a few more HP out of their car by fiddling with the fuel using their laptop while they're driving around on the street,

[athens7]

John-

I had no interest in tuning this car when I bought it, and I still don't. In fact, I paid $55,000 for my fully dealer built car with a Caterham USA supplied, new-in-the-crate SVT motor, specifically because I didn't want to deal with this type of thing. My last car (a Beck 550 spyder) had a highly tuned Type 1 VW motor, and I was constantly having to get it fiddled with. I bought my car because it was, according to Caterham USA and the dealer, the last of the new SVT 7's, using factory engine management and a factory wiring loom. I had debated waiting for Caterham UK & USA to get the non CSR Duratec package put together, but Cody at Caterham indicated that after market engine management would be necessary, and I wished to avoid that. He stressed the great deal of development work that they had done on the SVT package. As part of the purchase process, I discussed with both the dealer and Caterham USA the camshaft upgrade. It was presented to me as a bolt on, 20 hp upgrade, sacrificing a small amount of low end torque for more horsepower at the top. I was told in no uncertain terms that no PCM reprogramming would be necessary.

 

From the day I received my car, it has cut off every time I depress the clutch from any revs higher than 3000. Starting at 500 miles, it has developed first a cold hard start, now a hot hard start. All tuning and dyno work was originally intended to address these problems; the power issue is secondary. The issue isn't a pretty dyno chart, the issue is THE CAR DOESN'T WORK. Everyone's got an opinion (Cody, the dealer, blatchat members, USA7s members, etc), most of them conflicting, but no one's here but me, my local resources, and my $$$$. If the engine is sound, then there is no benefit to the cam upgrade, for I will have sacrificed mid range drive ability for no hp gain, and I will remove it, and return to the stock SVT configuration. If there is a separate problem, I need to resolve it, or the car will continue to function badly, regardless of which cams are in it. Unfortunately, the US distributor has basically washed his hands of me, and the dealer is 800 miles away.

 

The engine management for my car is Ford, but has now been reflashed with a custom Diablosport Predator tune. As you so eloquently point out, not designed for my exact configuration. But then my motor was built for a 2900 pound, front wheel drive car with a different transmission, so I don't know that the factory suppositions for my PCM are any better than, or even as good as, my custom tune. As to the adaptability of the Ford PCM, the longer I drove it, the worse it ran.

[Mandurath]

Having never even considered buying a new one, does it come with a warranty? Being in GA, near some pretty nice tracks I would think that surely there are some shops worth their salt.

[Al N.]

I think JohnK brings up a great point: why do many of us care so much about the peak power? About getting a printout of our charts?

 

I mean, if I didn't know my car was "down on power vs. the factory claim, even factoring in SAE vs. RWHP" (which it is), would I care? It's plenty fast for me, and feels like a rocket those few times I have the guts to really step on it. I'll never be able to keep up with a Super-Stalker on DOT slicks in the hills of Tennessee, but that could just be the difference in drivers.

 

Regarding Brad's initial cold start/cut out issues...I do think that is a slightly different animal. And one that should be addressed by the dealer as a way of solidifying his reputation. After all, if he helps with the problem, then Brad is much more inclined to promote that dealer to people who ask where they can buy a car just like his. Right now, it sounds like Brad is feeling he didn't get the car he thought he was buying.

 

That said, as much as we'd like to think otherwise, the whole warranty thing doesn't really apply here. As some of you know, I had several coolant hose issues in my first year of ownership (2005), but since my car was technically a 2003 (built in 2004)...any claim I might have had long since expired.

 

When I got my car, USA7s.org didn't exist (that I knew of, at least)...there was just the email list that many here are still part of. And back then, there was definitely a sentiment of "the Cat distributor and dealers don't really care about owners after the sale...owners are on their own and rely on themselves and other owners to sort things out". I don't know what the sentiment is with other makes....Stalker & WCM owners seem to love Dennis and Brian.

 

While I don't have any of these ill feelings about the dealer I bought from (Rex M. of Speed Classics) or about Cat-USA, I definitely think the onus is on owners to sort their own cars out. It's not a good thing or a bad thing, it just is.

[Mandurath]

You are probably right on the car part. The engine however is a different matter. Since its supposed to be a new engine, regardless when built, ford provides a warranty. Though, the cams may have voided that too.

[Al N.]

FWIW, if you have the 6 speed tranny, then I've been told that dyno runs should be made in 6th....it's direct then, with less loss due to gears.