Turbo or SC?? - Pros/Cons

[sheetwright]

I am running the stage two MPI at only 12lbs of pressure. With out the new MPI fuel pump I was around 17:1 on the A/F gauge, and with it I am at around 13.5:1, before my problem. I would seriously consider the pump at 10lb's. If you are going to stay lower 5-6 you will probably not need it, but if you get that power itch later you may need it. Mine is a bit different, cause of the engine mods, but 12lbs is only a little away from the 10lb idea. I would stick with Turbojamie, and Skydog with their ides since they have run the stage ones at sea level. The other thing to prove the sealevel thing to you. The guy I bought my kit from was in the mountains 11-15,000', and he didn't have to run a extra pump at 16lbs of boost, now I am having problems with 12lb's at sea level. Don't get me wrong the kit is great, and the customer service is great. It is just how many pounds do you want at sealevel??????
Next time my pipe dream might be the Impulse turbo. If those claims are correct of 17lb's with pump gas on the Nytro, and the Apex kit coming out soon. That would be awesome in the woods where racing fuel is limited.

http://www.ty4stroke.com/viewtopic.php?t=77540

 

[kinger]

I am running 10lbs and Allen just had it on the dyno and said nothing about needing a fuel pump?? I'll have to look into this.

 

[SPEED]

To put your minds to rest, refer to the Dyno Feedback section on this site,That was my sled on the dyno with those results. YOU WILL RUN OUT OF FUEL @11lbs boost @ sea-level We aborted the dyno session with my sled until we upgraded the pump. I cannot speak for anyone else results ,only my own experience.

 

[kinger]

Well depending on RPM I may make between 10-11 psi. Interesting, thought this was only a issue on stage 2's.

 

[TurboJamie]

For peace of mind I would do the fuel pump on anything over 10 psi. Myself Dan I honestly think you should get familiar with thing first and run 5 psi for a FULL season. Get familiar with the system and know what to expect before going balls deep. There is alot going on and alot to learn keep it simple and avoid frustration and down time.

MPI Stage 1 @ 5 psi will be more then enough fun in the trails.

 

[sheetwright]

Does the fuel issue change from turbo supercharger or style if all at similar pounds?

 

[mbarryracing]

For peace of mind I would do the fuel pump on anything over 10 psi. Myself Dan I honestly think you should get familiar with thing first and run 5 psi for a FULL season. Get familiar with the system and know what to expect before going balls deep. There is alot going on and alot to learn keep it simple and avoid frustration and down time.

MPI Stage 1 @ 5 psi will be more then enough fun in the trails.

Jamie, great advice.

 

[ROCKERDAN]

Hey guys.....

awesome info here and I really appreciate all your help....

from what im gathering it seems that at 10lbs boost,the apex fuel pump is "on the Edge" of keeping up.....it sounds like the pump is fine for trails,and some short lake bursts....but it also seems that for long hauls on some lake runs(over 1500 and up feet) I MIGHT run into issues where the stock apex PUMP cannot keep up.

Now i spose i could stick to stock pump and watch my AFRs closely.....but i think the way im looking at this ,is i want to do the job once and ride all winter and not having to wrench it more.

since the sled will be apart for everything,i think i might as well upgrade the pump from the getgo and be done with it.

I hear what everyone is saying about starting with LOW BOOST but again,i think i want to just do this once,and not have to get into swapping pulleys and all later when im bored with low boost.

I have pulled myself back from the edge of a stage 2 though!...lol,for that the cost of fuel system bumps things up where i dont want to spend that much.

so its looking like a stage 1 MPI kit with headshim and arp studs.

can someone tell me what pulleys i need to run 10-11 lbs?....will MPI install those pulleys to spec before they ship me the kit?....

on the pulley chart(see chart below) it shows 22/26@ 11.8lbs(10,800rpms) or 24/26@10.2lbs boost(10,800)...what is the pulley setup i want?...id love to run the 22/26 for 11.8lbs,is that safe with headshim on 91 octane though?

also....what is the best fuel pump for the money that everyone is using?

thanks
Dan

 

[ROCKERDAN]

like this

robbie thanks for the picture,that looks great....what is the third gauge,is it a temp gauge? nice.

do you happen to have anymore pics of how this looks from the front?...can you see the backside of all the gauges?...does it look decent from top/front?

another question,i see your boondocker is on your riser bolts....can you guys tell me ,is the RB3 more like a pc3...where it gets mounted under the hood out of sight?...i sorta like my pc3 stealth not being seen.....hoping the rb3 i go with will be similar and not right out in open.

thanks!
Dan

 

[TurboJamie]

Head shim and turbo run 12 psi on pump gas depends on what pump is though 91 - 94 are available at the pumps. If your stuck on going high boost I would go with the pulley combo that gives you 10 psi for added safety, and the fuel pump upgrade along with the head shim.

Tune and clutch from there.

 

[ROCKERDAN]

Head shim and turbo run 12 psi on pump gas depends on what pump is though 91 - 94 are available at the pumps. If your stuck on going high boost I would go with the pulley combo that gives you 10 psi for added safety, and the fuel pump upgrade along with the head shim.

Tune and clutch from there.

the main reason im wondering about pulleys is this...

for two years now ive been hearing about SC setups where you can run 5lbs and then swap pulleys for radar day and run 10lbs.

now that i have this chart,it looks to me like to do these swaps,you will need the 22 and 26 pulleys.....so now i see this swap will result in 11.8boost.

so i guess im just wondering what pulley combo MPI considers their stage 1 kit@ 240hp.

Dan

 

[ROCKERDAN]

just noticed that ChART shows 161,715 RPMS for blower....isnt the top limit of the stage 1 only 150,000??

can someone tell me,is that CHART possibly for a LARGER blower,like a stage 2 maybe?

i assume these type of pulley charts would be different for stage 1 VS stage 2 or 3.

Dan

 

[SPEED]

Pics Of fuel pump upgrade

This worked for me, I had two years of trail riding on this set-up with no issues ( I am not trying to steal this thread ,just trying to help out) I used a Walbro #P555-255-LPH Conversion took about a half hour .

 

[TurboJamie]

Its right there 26/22 combo looks like 5 ish and 11ish for boost.

Thats the combo for radar / trail

 

[aja636]

Dan, your asking alot of the same questions over and over and most here have posted the same answers.

MPI doesn't sell their kit with any boost # in mind, that is set by you, the user. For 240 HP @ sea level you have to run the additional fuel pump and the 26/22 pulley combo.

To make it short and sweet, Figure out where you want to set it and forget it. Be that 10lbs or 5 lbs. Cause every time you change boost level, you open the door up to having to add more fuel, change clutching, possible gearing depending on how you ride. And swapping pulleys is not a 10 min job either.

You can't have you cake and eat it to.

I have tried this before on a turbo set up and popped my head gaskets. So i set my sled up to run 16 or so lbs boost clutch it for that, Map the fuel for that and let it be for the low boost settings.

That being said, From what you are telling everyone here what you want to do. This is my recommendation.

A)Set the pulleys for 10 lbs. boost. 26/24 (boost numbers will run a little higher for sea level guys, air is denser)
B)Run your head shim, with 2 factory gaskets, one on top and one under. This will lower you compression just a shade more for safety.
C)Install 10 MM ARP
D)RB3 is IMO the best out there for fueling, spend the money go to hurricane and get him to map it for you.
E)Install upgrade fuel pump, either bosch, MSD or the set up SPEED posted, all will flow enough fuel, Hurricane can hook you up with the msd as well.
F)Get any gauges you like but have boost, temp, and A/F. And watch them all very closely, all the time.
G) Ulmer Racing has great clutching for the S/C set up, Call him and he will hook you up.
H)Add additional cooling if you haven't already, all you need is the rear exchanger under the tunnel extension will be all you need.

This set up will be pump gas safe for 99% of what you will do with the sled and still be enough to make you clean your shorts every ride.

If you know you are going to go run the balls off her for more then a 1/4 or 1/2 mile races, add a few gallons of VP or A/V fuel just to be safe.

All this And we(SPEED and I) ran his S/C sled hard for 2 years with out a problem.

Hope this helps you dan, and by the way...Welcome to the boost world, it will change you!!

AJ