Keep everyone up to date with how your project is coming along.
New to HP Academy. We’re building a land speed SC300 with two different engines for different classes - NA and Turbo - to be run at Bonneville. We’re starting in the Production class with the GE motor.
It’s tough to find resources on high horsepower NA builds because of course everyone goes turbo and if anyone asks about making NA HP people say their stupid for wasting their money and spend the time convincing them to go turbo.
Well, in the Production class you have to run what came in the car. We’ve never built a 2JZ before so this platform is all new to us. We’re starting to sketch out the initial build and was hoping to get some input from those of you who have some experience with the platform.
The class is a gas class so limited to a select set of gas products from VP Racing Fuels. Looks like we will be running C14. Possibly C14 Plus but we’re not sure if that fuel will pass tech. They just switched to VP last year so the on-site fuel testing hasn’t shaken out yet.
I’ve reached out to JE Pistons to see what what type of compression they feel they can get. I’ve found no high compression piston information online. Our tentative target is 14.5:1.
We will be running an AEM Infinity 506 standalone. EFI Hardware ITBs with 410cc injectors.
We’re sending the head out to an ex-Cosworth guy in Indianapolis. We had started discussing valvetrain components and the question came up on whether we wanted to run oversized valves. Really don’t have any idea about the flow dynamics of the GE head so I was looking for some feedback.
Some of the other components we were looking at were Ferrea Competition Plus valves, Ferrea PAC Allow dual valve springs and all the other associated goodies with the Crower 270 cams.
Our target is low 300s WHP and running up to about 9,000 RPMs. We really have no idea if this is feasible given the long run time at that RPM.
Any feedback would be much appreciated. We’re just trying to learn and consume as much advice as possible.
Hi Nick, unfortunately my only experience with the 2JZGTE is in turbo format, however I can still offer some guidelines for you. As far as the compression ratio goes, I'd expect that your in the ballpark with your target of 14.5:1. You may find that going any higher actually interrupts the flame front due to the large crown of the piston and you go backwards. I would expect that you should be able to get away with that CR on C14 but if you can use a better fuel then I'd advise it - C25 would be excellent if it's legal.
I think you're probably a little conservative with your cam profile, but at the same point, you're not really aiming for huge power - 300 whp is only a touch beyond 100hp/litre at the crank which shouldn't be a stretch. For an all out land speed record engine I'd probably be looking at a more aggressive cam profile to improve high rpm performance since low rpm is not too relevant. I can't speak too much for the valve size, but given the turbo drag guys are all running oversize it's a safe bet that there is power to be had. The people porting the head should be able to advise here though and bigger isn't always better when it comes to ports and valve size.
over size valves will be a must 1mm and valve seats also will need to be done to get the materials to match kelford cams can do a custom grind but you will ideally be as Andre has said larger in the cam 192-200 plus degress of duration and 10.5 plus mm lift to get the na head flowing
it will be suitable to run 10000 plus rpm.
and should be fairly easy to get the power reading your after
I'm not familiar with the current reg's, but I understand you have to use the fuel supplied by the sanctioning body (obviously to avoid accidental nitro' contaminations, etc), so the first thing would be to confirm the fuel that is to be used.
Next is to check what can, what cannot, and what isn't clear on what can be done to the engines, in either form. I would expect it to require an OEM block and head, but what else has to be based on OEM parts for the NA class - manifolds, management, transmissions, etc?
When you've got that sorted, you need to start planning your builds with what they're going to be used for in mind - with the NA, it may be quite difficult getting suffient compression as The Lake is just over 4200ft elevation, which reduces density by ~1/8th, and it is run in the summer, which further compromises air density.
Also, with the NA engine, you're going to be limited in the torque you can get out of the engine so, to get the power, you're going to have to wind it out - this will probably mean different rear end ratios (relatively easy to just unbolt one and bolt in the other), but will you need two different gearboxes?
With a turbo' engine, you're probably going to be looking at more cooling water and maybe different aero'.
All in all, it sounds like a really fun project, but I can't help feeling you're going to be better off concentrating on either forced induction or NA for the first year - there will be enough teething problems and expenses without adding to them the first time out.
Thanks for the feedback guys!
I was concerned about the increased dome on the piston and the added lift getting pretty cramped in the cylinder. We'll see what JE Pistons comes back with. Gasoline is limited to those VP Racing gasolines that have a dielectric constant of 15.0 or less and then they mention a bunch of other tests they might utilize - specific gravity, gas chromatography and mass spectrometry. Since they just changed fuel vendors last year they haven't done a lot of testing on various fuels. C14 passed. C25 might pass, we'll make sure to check on that one. C14+ might pass even with oxygenation. I don't think C45 has much of a chance of passing.
We're on the coast so we'll have about 1,200 meters of elevation up there. Air density at Bonneville is typical in the high 70's to low 80's in August. Thanks for the suggestion to look at a more aggressive cam. Will definitely look at that closer. Will report back on what we hear from the head guy.
Things are pretty open other that stock block and head. We're starting in Production class so first year will just be NA. Production class also doesn't allow any aero modes so everything will be stock. We've been looking at different transmission and rear-end options. Looks like we might be able to piece together a couple options based on what came in the SC300s and Supras that will give us different final drive ratios. Maybe save a little money on the drivetrain until we move to the forced induction class. We also have options for tire heights as well to change things up a little.
Curious what you all feel are the limits of the stock crank, GE rods and mains for very low torque, low HP and high RPM?
Head is off to Indy and full teardown almost complete.
Thanks again guys.
Can you provide a link to the relevant engine regulations/rules, please, getting a bit of a runaround looking myself.
The engines have been around for a long time, and I expect all the weaknesses to already be known and addressed - I'd suggest checking out the JZ forums because they will have a much better idea of what will, and will not, work for you. One big thing is, for example, the oil pump isn't reliable at elevated rpm, so that would need to be addressed - a good dry sump setup will take care of that and even have a potential power gain.
Other than that, decide on an RPM range for the short block and build the rest of the engine for that - you may find you can even run a stroker crank/alloy rod/ high pin high compression pistons with it. If you're using an ice chest for cooling with a blocked off radiator grill, might be well worth while using it to chill the intake air as density = power.
It's going to be difficult to make a call for the initial gearing, so if you can use a quick change rear end to fine tune it, it will help.
Rather than doing the same thing twice, build the fuel system, for example, with the capacity for the proposed forced induction. Same with other components that may be in common. If you expect to use the same car, swapping over the engines, starting out with quick release couplings, planning ease of removing/replacing the engines, etc, during the initial build can save a LOT of hassle and time later - there's never enough time, and if there is, there are better things to spend it on.
Anyway, sounds like a fun project!
Standard na none vvti rods are fine dont use the vvti na rods the cranks are all the same and handle 850-900 whp
the oil pump is good for 9000 rpm and by drilling out the return hole behind the front seal to 6.5mm you will stop the issue of the front seal blowing out at high rpm
Unfortunately SCTA doesn't publish anything online. You have to buy their regs book every year. The regulations on engine are pretty short and sweet for the Production class.
Displacement is limited to 3.014 L.
Head must maintain same number of valves and port configuration.
No blocking radiator of airflow. Radiator must be is stock location. Can upsize.
No quick change rear ends.
That's pretty much it for engine regulations.
That seems to strike out most of my thoughts...
Unfortunately you live in the US where everything seems to revolve around huge displacement and/or turbo's. In the UK/Europe racing is broken up my capacity with penalties for turbo's etc, hence people over here are generally a bit more aware of NA tuning.
As several have said, 100BHP is really nothing special, even WHP...that is a "rally" engine. Especially if you are using better fuel.
My last NA engine made 138BHP per litre (Note that this is UK BHP...engines built in the UK and then shipped the US mysteriously gain a surprising amount in the trip over!). This was a 1700cc inline 4 (Toyota 4AGE) running stock UK pump fuel, it was even intentionally a little restricted. The basic recipe was 2mm O/S valves, 320 degree 10.5mm lift (gross) cams, ported head, 48mm ITB's, proper intake and exhaust lengths and diameters and 12.7:1 compression ration. Given your larger capacity and better fuel I would probably go to 11.5-12mm lift cams (the "Full Drag Race Crower cams don't look a million miles off), 51mm+ ITB's and 13.5:1.
With NA engines, the key is always the intake system, starting with the valve sizes. On my VQ30 (3L V6) I am on 36mm inlets (stock, with 31.2mm stock exhaust cars) and this will support around 300-320BHP on 312 degree 9.7mm inlet with 286 degree 9.7mm exhaust cams on 47-45.5mm ITB's.
Beware people who tell you that you just need ultra high lift cams to compensate for smaller valves...these people usually don't understand head porting and don't own a flow bench. Have a look at how low the lift is on the various Cosworth NA cams.
Hope that gives you a starting point.
i'm sure you know but take any big 2jz turbo engine , look at the bhp then take every atmosphere of boost out of it , you will see there are many with the bhp in n/a
what i have seen and usually like to do is get the flow in the head 100% with whatever means valves ect , as when trying to make things up with cams moves the power up where as compression and head flow add power everwhere and then less cam takes away less compression all resulting in far better power band