TTP Engineering

iTrader: (465)

Wrapping up this week we are putting together another 4b11 Aluminum Rod Shortblock testing a new design for the Evo X. Using 86.5mm CP pistons we checked over block clearance with the newly designed rods. All checked out nicely. These units will be the most stout aluminum rods available for the Evo X and Ralliart 4b11. With 9.0:1 pistons and proprietary piston to wall clearance and ring end gaps set for high boost, high power, these engines are sure to be high revving, very stout and have a very light rotating mass which will equate to a free-revving 4b11, ready to get down to business on the track without the issues experienced by even stock 4b11 engines out of the factory.



In the stock form, the 4b11 has ring end gaps way out of spec that along with expansion can end up breaking ring lands and cause a mess of problems down the road from broken turbine blades to schrapnel bouncing around in the cylinders from pieces of piston rings entering other cylinders. There are a handful of evom members the same issue.



We have rectified the issues presented by Mitsubishi in stock form and taken them many steps forward with lightweight forged pistons, TTP A1000 aluminum rods, Cosworth main and rod bearings, ARP main studs, line boring mains, boring and honing +.20, pin fit rods, set ring gaps and seeing that it all gets assembled properly from the start this time around.



Here are a few pics of the fitting of our new A1000 rods for 4b11 Evo X and Ralliart 2009+.



At +.20 there is a ton of material thickness at the cylinder walls so no sleeving of the block is required with our engines.



Checking clearances to the main girdle and oil galleys. Everything checks out perfectly.

DRAG

iTrader: (3)

Do you have to do any clearancing for the rods? My eyes suck and I can't tell if the girdle is notched or not.

What are the stock ring gaps? Makes me wish I put a motor together instead of buying another stock one DOH!!!!

TTP Engineering

iTrader: (465)

The girdle fits perfect. The rods clear all 4 areas by 1/2" or so.

Stock ring end gaps specs I have not looked up recently however we have measured them in a stock block to .007

Most piston ring manufacturers recommend a minimum end gap of .004 inches times the bore diameter for the top piston compression ring. So for a 4 inch bore, the standard end gap would be .016 inches.

86mm stock bore = 3.38582677"
.013-.014 recommended ring gap

For a modified street performance engine that generates more horsepower and heat, the end gap should be opened up a bit to compensate for increased thermal expansion. The recommendation would be a minimum top compression piston ring end gap of.0045 to .005 inches times the bore diameter. For a 4 inch bore, the ring end gap on the top ring should be increased to .018 to .020 inches.

86mm stock bore = 3.38582677"
.017 recommended ring gap for modified street performance

For a nitrous or blown racing engine, the top ring end gap should be opened up to as much as .006 or .007 inches times the bore diameter. Now we're looking at a 2nd ring end gap of .024 to .028 inches in an engine with 4 inch bores.

86mm stock bore = 3.38582677"
.023-.024 recommended ring gap

NOTE: These recommendations are rules of thumb only. Always follow the end gap specifications recommended by the piston ring supplier or engine manufacturer.

DRAG

iTrader: (3)

I've seen a lot of tight ring gaps like that on OEM engines. That isn't uncommon and it seems to be a common trend in more modern engines.

Thanks for the info on the rods. I'm still leary about running aluminum in my street car considering the climate I live in. I run GRPs in my Honda and I love them, but I'm just leary. Maybe I'll give it a shot.

tephra

iTrader: (6)

wow nice looking parts.

hows aluminium for long term use?

hopefully I wont need these, but if I do i'll know who to ask

KPerez

UR approach to eliminating ring failure (https://www.evolutionm.net/forums/ev...misfiring.html) on the 4B11 is to increase the ring gap. However, will this also increase the potential for fuel dilution (https://www.evolutionm.net/forums/ev...l-problem.html) which potentially creates a whole host of other longevity problems?

Later, Ken

TTP Engineering

iTrader: (465)

If you have fuel dilution problems its likely due to poor tuning. Stock tune could be considered a poor tune.

KPerez

If U look through the earlier fuel dilution thread U will C that dilution was occuring in tuned and untuned X's. Perhaps Mitsu has close tolerances to minimize dilution which occurs in most cars to some degree but appears to be high in the 4B11 especially in the cold and with relatively low mileage. Not trying to "rain on the parade" here...just asking if U think this could be a consideration that may require oil changes<3k mi.

Later, Ken

TTP Engineering

iTrader: (465)

Using a high quality oil such as Amsoil Racing Dominator at proper intervals should not see any problems with fuel leakdown. We have not seen this to be a problem in any tuned Evo X's.

The TTP A1000 Aluminum Rods are designed for 450-1000hp applications where the best quality oil should only be used an at proper intervals for these power levels being run with them.

TTP Engineering

iTrader: (465)

We have been told by our machinist that there are sets in use with 75,000 miles on them.

When care is taken to build the engine to proper specs, there should be no issues with using them in a street car. In fact we have a number of Evo 8-9 engines being run with our A1000 rods as we speak.

To work, home, track and back again.

apagan01

iTrader: (299)

The topic about the fuel dilution has been discussed over and over,,, it has been very evident by evom members that have gone out of their ways to run oil analysis labs, to find that oils with high number of TBN will hold up to the abuse fuels put on them, you want an oil with a TBN of 10+,, when you see an oil that has been designed for hot fuels like, Ethanol, Methanol, Race gas and many others be sure it will be more than fine on pump, AMSOIL Dominator is designed for this matter.

evom use a high quality oil and you wont see fuel dilution at all.

Brokenevo

iTrader: (18)

thats awesome, how much for a set hehe?

TTP Engineering

iTrader: (465)

They are listed on our site, however we are accepting partial sponsorships at this time for high profile builds wanting to demonstrate their light weight, strength and ability to withstand high hp.

TTP Engineering

iTrader: (465)

Some more eye candy: