Our Tomahawk refresh

Discussion in 'Race 400/430/455' started by slimfromnz, Jan 20, 2016.

  1. slimfromnz

    slimfromnz Kiwi Abroad

    3.4kg per 1hp
    3.7kg per 1ft/lb

    Should be ok for the street :3gears:

  2. Jim Weise

    Jim Weise EFI/DIS 482

    7.5 lbs per HP.. that should work out just fine for you. :Brow:

    Expect your converter to increase stall about 200 rpm due to the new torque.

    That's a lot of compression for E-85, or are you running E-98? I might sweat 85 a bit for detonation..

    What lobe center is the cam ground on, and where is it installed?.. as I recall it's a 254/265 @.050 solid roller with .625 valve lift.. rocker ratio?

  3. flynbuick

    flynbuick Guest

    What does the vehicle weigh with a load of fuel?
  4. gmcgruther

    gmcgruther Well-Known Member

    E-85 has a similar octane to 112 that plenty for 13.5:1.
  5. gmcgruther

    gmcgruther Well-Known Member

    Photo of an E85 pump.
    E85 is a term that refers to high-level ethanol-gasoline blends containing 51%-83% ethanol, depending on geography and season (see Fuel Properties and E85. JW, here is a little insight.
  6. gmcgruther

    gmcgruther Well-Known Member

    Octane rating Edit
    As more effort is put into maximizing an engine to take advantage of E85's higher "octane", engines achieve greater power advantages. One car that has higher power on ethanol is the Koenigsegg CCXR, which on ethanol is the third-most powerful production car, with 20% more hp on E85 than on gasoline. According to the manufacturer, this is due to the cooling properties of ethanol. E85 has an octane rating higher than that of regular gasoline's typical rating of 87, or premium gasoline's 91-93. This allows it to be used in higher-compression engines, which tend to produce more power per unit of displacement than their gasoline counterparts. The Renewable Fuels Foundation states in its Changes in Gasoline IV manual, "There is no requirement to post octane on an E85 dispenser. If a retailer chooses to post octane, they should be aware that the often cited 105 octane is incorrect. This number was derived by using ethanols blending octane value in gasoline. This is not the proper way to calculate the octane of E85. Ethanols true octane value should be used to calculate E85s octane value. This results in an octane range of 94-96 (R+M)/2. These calculations have been confirmed by actual-octane engine tests." [12]

    Examples of this mis-citation can be found at the Iowa Renewable Fuels Association titled "E85 Facts"[13] which cites a range of 100-105, and a document at the Texas State Energy Conservation Office titled "Ethanol",[14] which cites a 113 rating.

    Some vehicles can actually be converted to use E85 despite not being specifically built for it. Because of the lower heating value E85 has a cooler intake chargewhich, coupled with its high stability level from its high octane ratinghas also been used as a "power adder" in turbocharged performance vehicles. These modifications have not only resulted in lower GHG emissions, but also resulted in 10-12% power and torque increase at the wheels. Because of its low price (less than $2.00/gal in some places) and high availability in certain areas people have started to turn to using it in place of high-end racing fuels, which typically cost over $10.00/gal.

    E85 consumes more fuel in FFV when the vehicle uses the same compression ratio for both E85 and gasoline, because of its lower airfuel ratio and lower heating value.

    Use of gasoline in an engine with a high enough compression ratio to use E85 efficiently would likely result in catastrophic failure due to premature fuel ignition, as the octane rating of gasoline is not high enough to withstand the greater compression ratios in use in an engine specifically designed to run on E85. Using E85 in a gasoline engine has the drawback of achieving lower fuel economy, as more fuel is needed per unit air (stoichiometric ratio) to run the engine in comparison with gasoline. The additional ethanol required for a stoichiometric fuel ratio helps compensate for lack of energy provided by ethanol's lower heating value (LHV), which is lower than the LHV of gasoline. I hope this puts E85 in a new perspective. I'm about facts not assumptions. If Royden is getting E85 from a performance shop like the dyno place he is at then his E85 is specifically blended. If not he does need to check for specific gravity and other things. If a car running 20+ pounds of boost on E85, Royden, you have nothing to worry about.
  7. gmcgruther

    gmcgruther Well-Known Member

    VP Racing Fuels Latest News

    TAKING E85 TO THE NEXT LEVEL - More Power, More Consistent Tuning

    SAN ANTONIO, TX - VP Racing Fuels today introduced C85 racing fuel, offering significant performance gains over conventional E85 according to Jim Kelly, VPs Director of Racing Fuel Sales. Conventional E85 gained some popularity because it was cheap and made some power, but it has a significant downside, said Kelly. In addition to requiring a costly E85 carburetor and completely revamped and upgraded fuel system, E85 is corrosive and very inconsistent.

    When you dont know if youre getting 60% ethanol, 80% ethanol or something else, its extremely difficult to tune, Kelly continued. Many engine builders have cited up to a two-jet swing in their tune from one batch of E85 to the next. By contrast, C85 is blended with the same degree of care and precision as every other VP fuel, with a consistent proportion of ethanol and every other component in every drum. It takes all the guesswork out of tuning.

    With VPs focus on power, weve engineered C85 to make up to 4% more power and torque than conventional E85, Kelly added. In addition to these performance gains, C85s higher quality pure components make it superior to E85 in terms of cooling effect, resistance to detonation and weve added corrosion inhibitors to fight the issues presented by ethanol.

    C85 will work well in drag racing, oval track, off road and virtually any other automotive racing application, in particular forced induction applications due to its lower vapor pressure. Tests of C85 indicate most applications will require richening up by 1 jet size, or 2-3% over current jetting.

    For racers who have already made the financial commitment to use an E85-type fuel , C85 is the best choice , Kelly said. For racers who want more HP and torque than conventional 110 and 112 type fuels without the additional investment in an E85 carb and fuel system upgrade, VP's MS109, VP113 and Q16 continue to be the best race gas alternatives for the money.
  8. buicksstage1

    buicksstage1 Well-Known Member

    There are a lot of people using E85 with 15.0:1+, smaller cams etc E85 has a evaporative cooling effect that is much greater vs gas and that further contributes to its detonation resistance compared to the same octane race fuel. I think Royden posted some where that they are also only running 30* I understand that fuel should be checked because there seems to be some inconsistency in the ratio's etc. I read that in the winter they go to 25% gas vs 15% in the summer so I wonder if they keep selling the winter blend until its gone. I haven't seen any e85 etc up here, I wish they did.
  9. Jim Weise

    Jim Weise EFI/DIS 482

    You could be correct Chris, I have not followed the lastest E-85 trends closely. Got any examples of a small cam 15-1 E-85 combo? I would be interested to see that.

    Mike Erickson, for whom I built, and just this summer updated, the first production Tomahawk, is a engineer who builds ethanol plants all over the central US. So, of course, we built that motor for E-85. He specifically had me built it at 12-1 back in 2010.

    We refreshed the bottom end with rings and bearings this last year, and put on a new top half. He did want me to up the compression as much as possible, without a piston change.

    From what he told me, when we discussed upping his compression ratio, was that he could deal with just about anything up to 14-1. He blends his own fuel, and often as not it's closer to E-98 than E-85.

    I dyno tested and tuned the motor to his "spec fuel".

    As far as winter blend E-85.. it's actually E-70. I just had a 8896 Dommy converted by Chris at Classic Motorsports in Sauk Centre MN.. he is very knowledgeable and experienced, well known in this area for E-85 conversions. I specifically asked him about winter blend E-85, and the long and short of that conversation was that he sold me 5 gallons of E-98 so I could blend up pump E-85 for the street 555 that will be on the dyno as soon as some parts show up.

    And then maybe have some for the supercharged 555 that will follow.

  10. Smokey15

    Smokey15 So old that I use AARP bolts.

    There seems to be a bit of disagreement with the compression ratio vs. E85. It doesn't really matter. Granted, it is not "needed" for its higher octane rating on a low compression engine, but it can, and is, being done. It all depends on the fuel delivery. Newer vehicles rely on the computer to 'adjust'. With a carb, it is all in the proper set up for E85. Compression at 12:1 was never too low.
    My Buick is just under that and I'll be running it soon.
  11. slimfromnz

    slimfromnz Kiwi Abroad

    The E85 we use is always 85%+ regardless of the seasons.
    I ask my engine guy about the lambda for the exhaust reading and he bought this up for me
    The right side reading is the one to look at
  12. slimfromnz

    slimfromnz Kiwi Abroad

    Guys, I just want to say that, I value everyone's input, because I put them all together and work out what will work best for me.
    I have to say that at 13.5:1, this engine loves the E85. I never claim to know much about the effects of valve events on an engine, but I reckon we have nailed it with this combo.
    I just love the 5300rpm data. 839hp @ 832ft/lbs. This engine was very control able on the street, how do I know, I bloody drove it. If you wanted to turn it up, just ease into the throttle. If you wanted to your stomach in the back seat while the back tyres were on fire, then you slam the pedal all the way to the floor. Buick power man!!
    It probably won't change much, just happen a 1000rpm earlier
    I wish I could take some of you guys for a ride in it.
  13. slimfromnz

    slimfromnz Kiwi Abroad

    My engine guy told me the stall would flash a bit higher now.
    No detonation on the dyno.
    .650 lift with my 1.6 rockers.
    I know when the cam went to Bullet, they reground it to the same specs. Not sure of the lobe centre, but think it was installed 4' retarded.
  14. slimfromnz

    slimfromnz Kiwi Abroad

    Just found this YouTube clip from over a year ago. This is a good indication of how it drove. Had 4 people in the car.
    Can't wait to try this again
  15. gmcgruther

    gmcgruther Well-Known Member

    Royden, I didnt mean to cause a ruckus but, many of folks back up in Michigan that I know which have your compression and some are higher, and power level the same but torque? No way. And they run E85 from well established places that only get the 85% ethanol or higher E-85. They swear by it. I see why now. I have riden in 1000+ hp cars before and they are absolutely freakin scary, especially on 12" inch slicks :-( :-0
  16. Thumper (aka greatscat)

    Thumper (aka greatscat) Well-Known Member

    You're on the wrong side of the road, did you have the camera upside down?:eek2:

    Impressive, to say the least.
  17. ken betts

    ken betts Well-Known Member

    I really like the big #'s and at only 6600rpm! Just think what a big cam and Good heads will do and at only 10,000 rpm!!! Awesome
  18. slimfromnz

    slimfromnz Kiwi Abroad

    No Gary, we live upside down
  19. slimfromnz

    slimfromnz Kiwi Abroad

    We are very happy with the power with small heads and cam
  20. Michael Evans

    Michael Evans a new project

    Less problems with small heads on the street

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