Got Boost? YEP! All 10psi without detonation! =) YAHOO!

[WESTCOAST JASON]

Before I say anything here I MUST praise DLM and Vipermed (scott). They have both, for no profit of their own, walked me through hours of tech support help with my Turbo car. Without them I am certain that I would not have found the problem/solution to my detonation/spark knock headache.

Thank You Doug. Thank You Scott.

That being said, I can finally announce that all 10PSI is being put into the motor with 91 octane gas and the car is NOT pinging or detonating.

The problem was so stupid I am almost embarassed to say it, but here goes.

During another day of changing/reading plugs and trying different combos of fuel pressure, retard settings (both on MSD and Piggyback) and plugs I was under the car checking on the flex pipes (thanks Scott, new ones are still fine!) and figured since the car was in the air I would check the fuel filter.

Yep. That was it.

The car has a intank pump still in place (it is a 255LPH Mustang unit from Summit I had installed back in the NX days) which feeds to the CPR (Aeromotive type) billet filter and then to the 1000HP CPR (Aeromotive) pump. I decided to check the fuel filter so I took it off and put it on the bench.

Upon opening it (the unit is a reusable type billet case with a purolator filter inside) I found that the filter was a bit dirty but looked fine. However, I put it to my lips and it was hard to blow through. hmmmm..... I went to the autoparts store and got a replacement and it to was not 'EASY' to blow through. Turns out it is a '10 micron' filter for what thats worth.

Instead of putting the new one back in I figured I would try without one as a test. I took the car out and it felt the same at 5psi. Oh well I thought. While driving back I realized all the retard was still programmed into the box. Ooops... I put the piggyback at zero retard across the board and just put the MSD @ 1 for testing. Wow, the car pulled great! I had not felt the 5 psi setting feel so powerful before.
I pulled over and cranked the manual boost controller up to 10 psi and drove again. Ear to ear grin, felt almost like the NX kit used to. Drove around a little more and was thinking maybe I should pull more timing out (no detonation to this point).

Low and behold, I was able to set the MSD to .5 (point 5) which pulls 1 degree of timing out for every 2 psi of boost. Now the car greatly SURPASSES the seat of the pants it used to be like with the NX (300HP) setting!!!!! I have now put a solid 300 miles on today alone and run 2 tanks of gas so far. PURFECT! I love it. Pulls SOOOOOOOOOOOO hard! 4th gear - 3000RPM (about 75mph) roll ons are the greatest! Smoked every street bike I could find on the freeway today with power to spare. I am AMAZED that a stupid filter could do this to me!! ARGH! Just the wrong part for the application I guess....
Scott and Doug both talked about it though and Doug SPECIFICALLY kept reminding me that fuel pressure is not fuel flow. I was told over and over that flow is important also. Right on the money guys! Now I just need to put the inline filter back in with a free flowing filter. Who would have ever thought? With that fixed and the oil control problems fixed by my ANGELIC-like, long distance phone techs, there are but a few minor (in comparison) issues to deal with.

Anyhow, thanks guys (and gals) and to all that have supported me with tech tid-bits. I know more about boost and Vipers than ever and it is because of this board and its members. Vegas and So. Cal members, PM me for your rides, no more cancels!!

Thanks again VCA!

 

[Paolo Castellano]

Jason, 10 pounds for 10 cylinders, sounds about right to me! I hope I will be OK with 11 PSI! LOL! Congrats! I am glad to hear that your car is running fine. Paolo

 

[HP]

I think anyone that's tuned in lately felt your pain.
Glad to see you turned it around - with a little long distance help.

 

[Doug Supercharged Vipers]

Jason -

I'm more than delighted for you! Good to see things are looking more positive. Your hard work is paying off.

By the way, a 10 micron filter is for fuel injection and should ONLY be placed post pump. A 100 micron filter is to be used pre-pump and can also be used post pump.

On another note, I have even a better fix for you regarding your fuel system since you are on a positive roll.

Regards,
Doug

 

[WESTCOAST JASON]

Thanks for setting me straight on the Micron thing DLM. (I always thought it was just another dead PC manufacturer..) =)

As one member humorously noted, I am VERY thankful that the rest of the fuel system I purchased with the kit is not 1/10th scale.

As far as driving feel, it is much like my dream of turbo charging originally was. It is like having my old nitrous setup on all the time and perfectly proportional to throttle. The car feels like it weighs about 10 pounds and is just awesome. SOOOO FAST!!!!!!! As far as the great mileage I was getting, that is shown to have fallen with the fix to about 10 MPG. I will know more once I stop driving the car like a kid with a new toy though and maybe I can get back to the pre-fix 20 I was getting on the HWY's

 

[Torquemonster]

Well done. The sense of accomplishment must be wonderful. Enjoy!!

re mileage. you should be able to get back to what you had earlier and better it. Not sure how flexible your setup is so these comments may not apply if you're a bit limited on the adjustments....

Turbo milegae varies wildly depending upon throttle, but if you feather it and just keep up with the traffic along the interstate you should be able to tune it to get at least stock mileage figures unless you dropped compression too much. A turbo gives better quality air at cruise - a forced swirl effect of hot air which vaporises the fuel better in the chamber. To take advantage of it - simply lean it out under the cruise vacuum range, but don't forget to richen it back up a bit for idle or it will idle rough, you can also run plenty of spark advance under vacuum - and I assume you run an O2 sensor. Optimise cruise vacuum mixture and spark and you'll get great mileage without hurting power at all. If compression is close to stock you will get better than the non turbo car did - until you run boost - then you can forget economy... but who cares - the rush is addictive right

note: most turbo cars run poor economy because their over zealous tuners run the [******] cars too rich. A little bit rich may be a poor mans way of compensating for lack of intercooler efficiency under boost, but there's no excuse for running too rich at cruise - its just wasting gas, and the mixture should revert to power mixture ratios the moment the vacuum drops close to 0.

If you really want to get exotic - try the UK Aquamist 3D mapped water injection system and run a lot more spark at boost - its brilliant. I ran 9:1 at 18psi boost with 24 degrees timing at full boost on pump gas - no problem and not near the limit - and got 33% better cruise economy than a stock 10psi car. Don't let any bozo tell you water doesn't work. Other guys trying what i did without water soon had a bucket full of broken bits. Water does not make power but it allows you to tune a lot more in - the only better method is to run a lot more octane. A safe conservative ballpark would be 4 degrees more at full boost with the water mapped properly. You better believe you'll feel another 4 degrees by the seat of your pants. You do need a low water red light and a water malfunction light if you don't have a knock sensor, and remember to top the water up each tank fill. They don't use much on the street, but you don't want to run out.

 

[Anthony - 98 GTS]

Well done. The sense of accomplishment must be wonderful. Enjoy!!

re mileage. you should be able to get back to what you had earlier and better it. Not sure how flexible your setup is so these comments may not apply if you're a bit limited on the adjustments....

Turbo milegae varies wildly depending upon throttle, but if you feather it and just keep up with the traffic along the interstate you should be able to tune it to get at least stock mileage figures unless you dropped compression too much. A turbo gives better quality air at cruise - a forced swirl effect of hot air which vaporises the fuel better in the chamber. To take advantage of it - simply lean it out under the cruise vacuum range, but don't forget to richen it back up a bit for idle or it will idle rough, you can also run plenty of spark advance under vacuum - and I assume you run an O2 sensor. Optimise cruise vacuum mixture and spark and you'll get great mileage without hurting power at all. If compression is close to stock you will get better than the non turbo car did - until you run boost - then you can forget economy... but who cares - the rush is addictive right

note: most turbo cars run poor economy because their over zealous tuners run the [******] cars too rich. A little bit rich may be a poor mans way of compensating for lack of intercooler efficiency under boost, but there's no excuse for running too rich at cruise - its just wasting gas, and the mixture should revert to power mixture ratios the moment the vacuum drops close to 0.

If you really want to get exotic - try the UK Aquamist 3D mapped water injection system and run a lot more spark at boost - its brilliant. I ran 9:1 at 18psi boost with 24 degrees timing at full boost on pump gas - no problem and not near the limit - and got 33% better cruise economy than a stock 10psi car. Don't let any bozo tell you water doesn't work. Other guys trying what i did without water soon had a bucket full of broken bits. Water does not make power but it allows you to tune a lot more in - the only better method is to run a lot more octane. A safe conservative ballpark would be 4 degrees more at full boost with the water mapped properly. You better believe you'll feel another 4 degrees by the seat of your pants. You do need a low water red light and a water malfunction light if you don't have a knock sensor, and remember to top the water up each tank fill. They don't use much on the street, but you don't want to run out.

You ran 18 psi in a Viper???

 

[Torquemonster]

I wish!

No, but the principle is exactly the same... my engine had 4 valves, the pistons had a ceramic coating on the crown and teflon coated skirts, but the chambers were not polished or coated, and the heads were stock. The coatings added safety margin and power but the 4 degrees advance advice with water does not require coatings - just common sense in engine build like deburring rough edges in chamber etc. The best anti-detonation protection is a tight quench (0.040"), with a dish to get compression back to boostable levels.

18psi = 122% power increase on base engine if done properly. That can be exceeded, but most installations will fall short due to bottlenecks somewhere such as unoptimised intercooling etc. So if you build a 650hp Viper engine at a given compression ratio then add 18psi you should have 1440hp if everything else was matched.

I often drive a Skyline with 22psi on its 3 litre straight six. At 1 bar (14.7psi) boost it has instant and seemless power and acts like any other 400hp car with a lot of torque. The difference between 1 bar and 1.5 bar however is like the difference between a lightning bug and lightning! The "sudden rush" is replaced by a brutal kick and you are simply hanging onto a torque steering AWD car and shifting gears for all you're worth. High boost is a blast, but with RWD it'd be a real handful as the higher boost pressures normally come on with brutal speed - this can be managed by computer, but its like pouring water on the fire you just lit!

10psi on a Viper is sensible and good for a 68% increase over the base engine.

 

[WESTCOAST JASON]

Thanks for the details. I have heard of a number of people having good luck with H20 injection. I will do some more fine tuning how you mention also. I do have an A/F rich/rean gauge (Tomei) so it will be fairly easy to know where I am at. I am just tickled right now with the performance and am sure that I am running harder than normal while the 'novelty' is still here. Additionally, I have become sub-conciously 'trained' to be light footed over the past months since detonation was such an issue. That, I am sure, contributed to the great mileage I was getting (along with the restricted fuel flow that is). I have noticed that I still get a mis-fire light when doing light throttle acceleration at low rpm. I have NOT checked the coils yet, but the wires are new and plugs were changed daily for a while during testing. I know there was an TSB on the V10 truck regarding cross firing from wire routing, could this be an issue on the Viper with the extra cylinder pressure?

 

[Torquemonster]

Jason - you say "light throttle" misfire, what does the boost/vacuum gauge read at these times?

If you are still on vacuum, cylinder pressure should be normal. Only if boost is starting will pressure be up... clarifying the gauge reading at the point of trouble will assist those more qualified than me to give you an opinion.

 

[WESTCOAST JASON]

The gauge is still in vacuum when it does it most of the time. If the car did not have turbos I would guess it would be enough to show zero on the gauge. I get a headache trying to figure if there is boost modifying the point of where vac would no longer be shown.... light throttle situations, you can hear the turbos whine up but still not show boost on the gauge, yet you can for sure feel the pull. The gauge gets it signal directly from the manifold. Figuring out the answer to your point is complexing..... (I feel like Austin Powers when he was discussing time travel........ "I've gone mad")

 

[Torquemonster]

Ok... there shouldn't be boost in the cylinder until it registers positive on the manifold... are you confident it is not detonation and simply an electrical or fuel problem?

Here's a test. Run octane booster - a good one like NO2 Race Booster. If the problem goes away - that's a clue its probably detonation. If the problem persists you can relax a bit and try and isolate whether fuel or electric.

I know from tuning my old turbo engine on a laptop that "pockets" of detonation could appear in the weirdest places, but if you have a good map of the whole EFI system, you can isolate each pocket and fix it. I used to race around the circuit having a ball, while my tuner would play on the laptop with these "zones" - hundreds of them. He could maximise spark advance across a range then retard it just in the little pockets that needed it - often just a single 100rpm zone. So you could have an advance curve that looked like a zig-zag - but it meant you got maximum spark and only ******** where it needed it instead of the normal safe method of right across a whole range which hurts performance significantly. If you cannot do this, you may need to look at tuning the entire transition area between vacuum and boost to get rid of the problem... or live with it. It may be as simple as the retard is not fast enough.

If its very mild and at light throttle - an engine can live with that for years... but I'd be like you and have to fix it... just to feel better.

 

[GTS Dean]

The problem was so stupid I am almost embarassed to say it, but here goes.

I decided to check the fuel filter so I took it off and put it on the bench.

Scott and Doug both talked about it though and Doug SPECIFICALLY kept reminding me that fuel pressure is not fuel flow. I was told over and over that flow is important also. Right on the money guys! Now I just need to put the inline filter back in with a free flowing filter. Who would have ever thought? With that fixed and the oil control problems fixed by my ANGELIC-like, long distance phone techs, there are but a few minor (in comparison) issues to deal with.

Power output is directly related to MASSFLOW of fuel and oxygen. They both have to be present in the correct amounts.

I haven't heard an apology yet...

 

[jimandela]

Jason,
Congrats!!

 

[WESTCOAST JASON]

[/QUOTE]

Power output is directly related to MASSFLOW of fuel and oxygen. They both have to be present in the correct amounts.

I haven't heard an apology yet...

[/QUOTE]

Guess I'm lost on the apology comment....

 

[jp]

Jason, Doug, which fuel filter should I use to not get leaned out?

 

[WESTCOAST JASON]

I have learned that when filtering from the tank to an aftermarket pump, you need at least 100 micron to avoid flow restrictions. Many of the 'cool' billet filters only come with a 10 micron filter, which will not support 80-100% horsepower gains. You can filter with a 10 micron unit on certain setups, but boost is not one of them. Check with Doug or Scott specifically on your setup....