Roush S351 Fuel Pressure Question

9

96 S351R

New Member
Oct 17, 2004
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#1
Hello everyone... new member here with a question.

A few months ago, I purchases my dream car, a Saleen S351. The car is everything I hoped it would be, and more. Although I don't drive it much, I LOVE it!

It has one quirk which I'd like to get worked out. The car falls on it's face at just over 5,000 rpm. Right around 5,100. It has increadible power up to that point, very fast! I had initially blamed the problem on the MSD ignition which was installed before I bought the car. I figured the rev limiter might be kicking in. This turned out not to be the case.

I decided to watch the fuel pressure while under boost, thinking the car may be leaning out at 5k. I didn't notice what I would call a significant increase in fuel pressure at full boost. Maybe 5-6lbs increase. Since the car is not equipped with an FMU, I didn't expect a HUGE increase, but more than 5-6lbs.

So my question is, what kind of fuel pressure are you fellow S351 owners seeing under full boost?

My car is equipped with an adjustable fuel pressure regulator, and static fuel pressure is set at around 35lbs. I'd like to hear some feedback before I start tinkering with the regulator.

Thanks!

Any other idea's/opinions or possible culprits are also welcome!
 

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#3
Yes, call Mark at his shop. He will help you out.

What I can tell you is that before I blew up my motor at 5,100 miles I had the FMU with the boost retard adjustment and my fuel used to spike at 80-90 at 9-10 lbs. of boost with stock injectors. That is bad. Also, mine is a 95. My car would fall flat at around 5,300. You are probably running out of fuel at 5,000. Your car probably has the Edlelbrock Performer heads if its an early 96 car like mine. They don't flow worth Sh#*. Also, our hacked Cobra intake would have been better left alone also. They did leave it alone in later cars. Your fuel pressure should rise all the way up with boost depending on what injectors you are running. The 97 update cars don't usually come with a regulator. What else do you have going on? Upgrades? I don't want to lose the look of my car but if you want your car to pull all the way up you should look into some AFR 185's and the Trick Flow R upper and lower intake and a new more agressive cam. The Saleen custom S351 grind cam is just a mellow Crane cam and is also worthless. There are two types of S351 owners. Those who have lots of miles, and by lots I mean 35-30K miles on them and they drive it like they are driving Miss Daisy. The other half are like me and bought this car to put my foot in it.
With a decent tune and powerpipe ( don't pully down and don't cog drive it )you can see 600 RWHP with our cars with that combo.
I'm still on my safe tune so all of the timing has been backed out of my tune and I have only been running a couple of pounds of boost until I break it in so I can't give you an accurate fuel pressure reading from a healthy car.
THE BEST THING YOU CAN DO for your car at this very moment is go get your car dyno tuned and GET RID OF ANY detonation. EVERY SINGLE S351 that came out of Saleen ( 94-99 ) even the 99 cars and yes I mean ALL of them have a ridiculous, totally worthless tune. They were so worried with the emissions problems they never got any of the tunes right even with the N/A cars. Sorry to tell you your bottom end IS NOT forged. Unless the previous owner already rebuilt your car you are driving a R-Code grenade. Also, if you have no FMU you may have the also worthless 97 upgrade. Well, near worthless without a good tune. Do you have a six speed?
I love my car and will never sell but there is a lot to learn about owning one of these cars. After you talk to Mark, give Joe a call at http://www.chicanesport.com/

Joe worked at Saleen from 1988 until the mid to late 90's and knows almost everything you need to know about your car. He rebuilt my motor. He also was on the build team that built your car. Here's the bonus. He has a fellow named Mike working there now and he is a former S351 employee. He knows more about S351's than anyone on the planet. Hands down. Like I said the best thing anyone can do is go get your car tuned right after you buy it.
Your car will love you for it.
 
#4
Perauto and marcus95, thanks for the replies!

Mark, when would be a good time for me to call? Any time or day preferences?

I'm still gathering info on this car, but luckily, a good friend of mine happens to be the mechanic who performed some minor tuning on the car before I bought it. While it was in his shop, he installed the MSD6AL ignition system, and an aeromotive fuel pressure regulator. These are the only known mods to the car. I also understand that the car was sent back to Saleen, due to emissions trouble here in Colorado. Evidently, they switched from eec4 to eec5, required for the modle/year in CO. When the car was returned from Saleen, it was taken to a dyno. They tweaked the car a bit, and the car produced 455 rwhp.

I love this car...I'd been dreaming of owning one since I first saw one in 1994. Has been my absolute favorite car since that point. It now sits in my garage, which is literally covered in Saleen paraphernalia! :D I mention this, because like you marcus, I bought my car to drive, but do not want it changed much. I'm willing to upgrade the internals once it's time to do so, but wouldn't want to change anything external...even though there are better parts out there. Even the Frankenstein upper intake! lol It gives the car personality IMO.:)

My car doesn't have the six speed...just the 5 speed.
 
#5
96 S351

I also have a 96. Mine never got the electronics mod from Saleen. Probably a blessing though. I ended up installing a F.A.S.T DFI system. I did the usual fuel upgrades (255 intank pump and a T-rex, aeromotive pressure regulator an 99 S351 fuel rails). My car also has a healthier cam but, with the stock intake it won't pull much over 5500. That will have to be changed to change the RPM range. I would recommend a TFS. Mine has Bennett Racing stage Twisted wedge heads, one of their custom grind camshafts, 9 to 1 pistons, and is pullied for only 5 lbs of boost. Without a power pipe I made 496 RWHP and 510 RWTQ. I didn't install a power pipe because I didn't want to cut the fender apron. That killed alot of potential for the car but, I already have a car to take to the track. What is your bumper number? I own #13.
 
#6
S351"Animal" I can see where you came up with your name!! I've been calling my car "wicked bit#h" since I first drove her! lol

I appreciate the reply and info. I'd like to turn the power up a notch, just for the heck of it. On one hand, my conscience is telling me, leave the car alone...it's fast enough. On the other, it's telling me "too much is never enough" :D

I'm stuck in between a rock and a hard spot on this one. I want to upgrade my engine, but don't want anyone else working on the car. I consider myself a decent shade tree mechanic (3 supercharger installs, 1 turbo, 1 engine swap, 1 upper/lower intake swap and two tranny/clutch swaps) but I've never been inside an engine. In short, I know how they work, but have limited hands on experience inside.

I'd like to add forged internals, a better cam (old one will be in a display case) :hail2: and some wicked heads. I just don't feel comfortable dropping it off at the local Ford dealership to perform the work. The old adage "if you want it done right, do it yourself" keeps popping up in the back of my mind.

My good friend, who happens to be the pro mechanic who worked on this car before I bought it, has offered to help with the mods...but my love for this car tells me to get to know her myself.

What would you guys recommend? I don't want to push the limits to the point that I hurt the block, but I want to maximize my cars potential, without pushing the envelope. Suggestions?
 
#7
96 S351R said:
Perauto and marcus95, thanks for the replies!

Mark, when would be a good time for me to call? Any time or day preferences?

I'm still gathering info on this car, but luckily, a good friend of mine happens to be the mechanic who performed some minor tuning on the car before I bought it. While it was in his shop, he installed the MSD6AL ignition system, and an aeromotive fuel pressure regulator. These are the only known mods to the car. I also understand that the car was sent back to Saleen, due to emissions trouble here in Colorado. Evidently, they switched from eec4 to eec5, required for the modle/year in CO. When the car was returned from Saleen, it was taken to a dyno. They tweaked the car a bit, and the car produced 455 rwhp.

I love this car...I'd been dreaming of owning one since I first saw one in 1994. Has been my absolute favorite car since that point. It now sits in my garage, which is literally covered in Saleen paraphernalia! :D I mention this, because like you marcus, I bought my car to drive, but do not want it changed much. I'm willing to upgrade the internals once it's time to do so, but wouldn't want to change anything external...even though there are better parts out there. Even the Frankenstein upper intake! lol It gives the car personality IMO.:)

My car doesn't have the six speed...just the 5 speed.
Click to expand...


Nice.
Sounds as if you have a nice unmolested car. How many miles on your car? In Colorado you can get 93 octane out of the pump. Right? . We only get 91 out of the pump here in Calif. When did your car go back to Saleen? Back in 96? If it was later than that they should have done the 97 upgrade. That tune still sucked but at least you get a six speed, new fuel rails, new stainless steel fuel line, mass air, injectors and OBD II
Ok, your car made 455 RWHP. That is good. You have a nice healthy car. My car made 434 RWHP (dynojet) on the pump gas out here, in stock form with detonation, stock Saleen tune.
"Animal" Didn't your car come with a T-rex? It was noisy and worthless on my car. Did you mean you now have a 255 and a boost-a-pump now? Out is the FMU also.
I know you don't want to trim your inner fender but my Anderson Powerpipe was the single best thing I did for my car. That powerpipe woke my car up. Our cars (forced induction 351's) really respond well to a powerpipe. I am making 400 rwhp now with the timing backed way out and no boost. I had my motor rebuilt with forged internals only. No stroke or bore. Original cam, heads and intake. The only additions I have made are 47lb injectors ( may be too small, wont know until next week), Anderson powerpipe, Vortech fuel rails, Aeromotive regulator, Probe Ultralite roller rockers, lightening mass air and stainless fuel lines. My motor looks completely S351 stock. Oh, yea, I lowered my compression down to 9.0 to 1 compliments of those forged Probe pistons so I can run 2-3 pounds more boost hopefully without any problems.
96 S351 R, do you get any detonation at all?
Oh yea, un motor related. I installed HyperCoil coilovers 375 lb in the front and it got rid of the bouncy feel from our cars. Maximum Motorsports CC plates and GlobalWest subframes with seat supports round out the other mods on my car. The powerpipe first, best addition to my car. Second was the coilovers.
Animal, install a powerpipe. You wont regret it. With your combo you could make some more insane power. Are you still on your stock bottom end?? I am jealous of your cylinder heads. It's either those or the AFR's. Damn. I need them. Take care guys.
 
#8
Long story on what my car came with. When i got the car it was far from stock. Dyno'd at 1200 RWHP a few days after I bought it. I put it back relatively stock. Here is a list of internals: SVO block,Scat forged steel crank, Scat H-beam rods, Venolia custom pistons, TFS twisted wedge heads from Bennet racing along with one of their custom camshafts, jesel shaft mount rockers, stock upper and lower intake, 75 MM throttle body, no mass air, 42 lbs injectors. I run a 3.33 pulley on the vortech. I would like to go with a power pipe but, I just go through replacing the inner fender apron and don't really won't to go through that again. With the FAST system I only experienced detenation once. That was do to it blowing out an injector o-ring and leaning a cylinder out! You mentioned that with the upgrade from Saleen they installed new fuel lines. who should I contact to get those? Would Joe at Chicane have a way to get them? 96..I personally wouldn't see a problem with a few mods. For the engine I would take the stock one out and start from scratch. The only thing I might keep would be the block and the heads if you have them opened up. Marcus....You should have any problem running the 47 lbs injectors. The should be plenty unless you step it up past about 550 rwhp. Personally, If you plan on going further, upgrade to a low impedence injector driver and run low impedence injectors. I had problems in the past with the 55 lbs high impedence injectors. I have the Anderson rengade power pipe set-up I could install on my car from when I was running a YS-trim on it. I built the motor so that if I ever decided to I could step it back up to that level. I had a 410w with a YS, TFS high ports, and the same camshaft I am running now and made 844 rwhp at 15 lbs of boost. I miss that! Just couldn't do it on pump gas. With the current moro I have no issues there.
 
#9
Yea, I hear ya.

Sounds like you had quite the monster on your hands when you bought your car. I too have become old and past the days of enjoying driving the truck down for more race fuel just to drive the mustang around for a half hour at 700 hp.
I just want decent power on pump premium with lots of driveability. There is nothing wrong with 400 rwhp, but our cars were advertised 495-500 hp crank and thats just where I have set the bar (rwhp though) You know what I'm saying? After the forged rebuild ( I love Scat, they are literally across the street from me at the beach here in So. Cal. ) they do some really nice work, I just feel with the combo I'm running now I should be able to get 500-550 rwhp safely. You know what combo I'm running so I'll post after my dyno session this week.
About your fuel line. I opted to go with regular stainless fuel lines just because that's what Saleen used to go with their 97 upgrade. I really wanted to go with Chicane/Goodridge Teflon steel braid lines. If you want a nice upgrade cal Joe over there and have him make you a set for your car. They are fantastic. Like you already know Joe was at Saleen during the S351 days. He made my stainless set there.
I can see why the powerpipe is not high on you list from the mods you already have going. Again, my car really responded well to it.
Animal, are you running a YS trim on your car now( from the 1,200 hp motor) or an S-trim ( stock S351 fare) ?? Also, what kind of boost are you seeing with your combo and that stock pulley? Yea, I think that I'll be ok with my 47 lb injectors too. Hope so. I really want to mothball my cam and go with something a little more agressive but

new Cam
AFR 185's
TFS Trick Flow R upper and lower = more money than I want to spend right now.
another tune.
I guarantee I could see 600 rwhp out of that at 6300 rpm. Do I want to? Yes. Does my wife? Maybe if I told her she could spend $2,500 at Pottery Barn next weekend. So no. So there you have it. Damn.
 
#12
How much fuel pressure are you guys seeing at 5lbs of boost. How much at idle. I don't use a FMU and mine is set at about 50lbs at idle then only jumps up about 5-10 lbs at the most under boost. When I had my nice fuel system under the car it would hit almost 95 lbs of pressure under boost. Alot more motor and boost though..
 
#13
Hey guys...no problem on "adding more" to my thread. I don't see it as hijacking...I wanted to read lots of feedback about S351 motors.:) You both are giving me some great idea's on where I want to go with my car. Proceed!

S351R"Animal": I'm seeing around 35lbs of fuel pressure at idle. I'm thinking it's time to crank it up a notch. I'm still thinking it's simply running out of fuel above 5k. Also, my car is #19. A white coupe with black Recaro leather.

marcus95: There are 28k miles on my car. Looks pristine for that amount of mileage though! As close as a car could be to flawless. Not even the "rock chips" so common with CO cars. I'm just running 91 octane in my car, although I do add octane booster (NOS) to every tank. 3 tanks since owning it. lol Wish we had 93 at every station though! My car was sent back to Saleen in 2002 I believe. They didn't change out the tranny to a 6 speed, but at least Steve signed it! :D Also, no noticeable detonation as of yet. Hope to keep it that way!
 
#14
96S351R: Congrats on getting your dream car! :hail2: I too love these cars just way to much, its a really expensive sickness that we have in common. This is an excellent way to get idea's for your baby. You can also visit www.saleenchat.com to talk on that forum with Saleen owners (I know Scott, aka "s351r animal" is on that site as well. You can also go to www.SaleenClubOfAmerica.com and check out the new nation saleen club that was just born the 1st of this year. The president of the club is moving to Colorado the beginning of the year and I know that the National Show is scheduled there next year as well (I'm guessing that is where you are located, judging from an earlier post) Just have to say Hi to the other two before getting to your topic:

Marcus: if you can make it down this weekend, we are most likely meeting Saturday morning at Cyrstal Cove in Newport Beach (weekly morning show/cruise/doughnut run). I have to get together with Dennis (00 s281 sc Coupe) and Todd (01 S281 N/A coupe) to finalize the planning. We are most likely going to do the Cove and the Donut Derelicts in Huntington Beach on a rotating bi-weekly bases. We were in HB on sat the 6th and hopefully this sat the 20th in Newport. We want to switch it up so we don't get sick of seeing the same car's week in and week out......

Scott: saw your wheels on ebay. By chance do you have a spare 18" x 10" speedline alloy rear wheel laying around?? Most likely not, but hey thought I would ask :shrug:

Getting back to the topic at hand: My speedster (1997 S351"R" #01) fell flat on its face @ 5100rpm the last time it was on the dyno. It maxed out at 470rwhp and 510rwtq @ 8lbs of boost. To my knowledge, it does have the stock fuel system from Saleen (36lb injectors, vortech fuelrails, don't recall which fuel pumps) however it happens to be the press car/formerly Tony Johnsons personal car so who really knows what tricks they may have done to the car. When I spoke with Mark @ performanceautosport, he did mention that Saleen had the rev limiter set @5100rpm on all S351's leaving there facility (spec sheet says 5700). That might explain why mine hit the wall at that point, although the air/fuel ratio was dropping and dropping very fast. The fuel pressure gauge sits at 35 lbs at idle but I don't recall where it hits under full throttle. (To busy hanging on for dear life :p) Car just hit 20,000 miles this month

The coupe (1995 S351"R" #11) was on the dyno with the previous owner(just bought the car on March 1st of this year) and it hit 420rwhp and 440rwtq @ 6lbs of boost. Just like Scott's car, there is no power-pipe due to not wanting to hack the car into pieces (as of yet). But the previous owner did upgrade the fuel system (42lb injectors, 255lph intank pump, T-Rex inline pump). Car runs strong, but under full throttle, there is detonation thanks to the beautiful Saleen tune. This car is what I like to call my daily driver, just hit 64,000 miles today!!!! But it really doesn't get started daily. I live on-site where I work so I can walk to the office. Nice to see you on board, hopefully we will see you on the other board as well.......you too marcus :p
 
#15
Saleen did set the rev limiter low but, with the factory intake it really doesn't make a whole lot of difference. I believe it was 5300 rpm. I could be wrong. I tried to get Saleen to do the conversion on my car since it never was EPAA compliant but, they refused and I haven't pursued it further since the only reason I wanted it was to pass emissions. Plus I haven't had the time to talk to a lawyer. I may have to have it done anyway do to moving around again. I may end up on the West Coast again sometime next year and the military no longer allows you to keep your car registered in your home state! California was the reason for the change. Sorry, I don't have any spare 18X10 rims laying around. Wish I did. I actually need a set for a car I have.
 
#16
Good thread! Probably more information in this one thread than I have ever seen on S-351s in any forum.

My 94 S-351R was upgraded to 97 Specs by Saleen and I have no problems with the tune or detonation. The emissions were extremely clean (even with the Bassani X pipe with Cats). When I made a visit to the dyno after purchasing the car in 2000 it made 430 rwhp and 430 ft lbs of torque with the stock S trim Vortech that made 8.7lbs of boost, 36 lb injectors, Vortech fuel rails, and a standard Vortech inlet (my inner fender was already trimmed by the Saleen Race Team when they built the car) so I am sure that is why I am getting a bit more boost than some of the other cars mentioned. I don't drive my car that hard, but I don't recall the car falling on its face @ 5,100 rpm? The max RPM I have seen is @ 5500-5700 RPM with the car still pulling like a freight train lol.

Lets keep the info flowing any chance at getting Joe or anyone at Chicane to chime in here?
 
#19
fabled horse update

Ok guys. Went to the dyno today. I'm lookin at my dyno sheet right now. I'll see if I can get a scan on this weekend. Heres what to report.

My 351 motor as it stands.

Stock bore and stroke 351 block
fresh forged crank, rods, Probe pistons 9 to 1
S351 Stock un ported Edelbrock 5.0 performer heads
Stock upper and lower intake
stock Saleen S351 cam
47 lb injectors.
lightning 90 mm mass air
Anderson Powerpipe
stock s trim, stock 3.33 pulley
Vortech fuel rails and stainles fuel lines
Aeromotive fuel reg.
stock headers
bassani x with two cats
stock Borla exhaust
new 255 lph pump, new filter, gas tank flush.
oh yea, my FMU is gone as well as the t-rex.
That pump is supposed to be good for 500 hp but is dying on me a little early. Ambient temp was 73 degrees out and I'm at sea level here. I don't know what the humidity was but it was low. dry out.
So really what I have here is a stock bore and stroke forged 351 with the only mods being powerpipe, injectors and 90 mass air. I made around 8-10 lbs of boost before my motor let go stock. At one point today I saw it upwards of 565 rwhp and 585 torque at 13-14 pounds of boost?? from ehat I could see across the room and my tech said unsafe there was probably around 600 in there. My car responded in a huge way ,powerpipe with the same pulley. The ads did not lie as the powerpipe alone made 3-4 more lbs of boost.
Detonation, mass air pegged at 4.88 running out of fuel again at 4,600 rpm, he backed out the timing where it is left at right now at 452.5 and 472.6 max torque. A little dissapointing. My goal is at least 500 rwhp (91 octane). He ordered 80 mm and a boost a pump. At this point he wants to do that and actually pulley up just a tad to lower the boost a bit. He claims I will be right where I want to be when we get that fuel issue fixed next week. I'm trying to think about what I forgot. I am trying to stay on the conservative side so we will see what happens next week. I wish this was an old Camaro or something and I would just put together a little methanol injection kit to it. Anyways, that was my two hours at the dyno today. My tuner said AFR 185's, more agressive cam and TFS R intake and of course fixing my mass air problem and the boost a pump and I can run 600 rwhp all day on 91 octane. I don't know though. Other than my powerpipe my motor looks completely stock. That is the way I want to keep it. I also believe my fuel presure regulator is acting up and sending fuel back in. At idle now I'm making 30 lbs and on boost it only comes up to a little over 40 so I think I have some work ahead there. Most important is getting this car some more fuel.

Rob, thanks for the invite but I have to show some San Diego clients around the beach up here all Fri. and Sat. You know we have to work when the mon-fri guys have the weekend off. Damn. Are you going to keep the meetings (dates) on your website so I know when you are heading out again???

Take care
 
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