420A internal build options?

[rc000e]

I have a customer build coming this week. The car is a 99 with a 420a. The build will include my own turbo manifold, charge pipes, head work, tuning, etc.

The budget is adequate, but I think we're coming up short due to the small market for 420A internals. The only viable option I see is the Eagle H beams, and the Je's.

What my question is, has there been any discovery in terms of an "intermediate" internal option. I'm looking at a possible race prep like I've done for road race engines where stock internals are required.

The deburr piston prep works well to suppress detonation but the cast piston in 420'a, from what I'm told, isn't highly reliable. I can improve rod strength about 25% through prep, but I think due to the lack of affordable, capable management, the internal strength of these motors hasn't been properly tested.

So are there any intermediate options?

 

[VelocitàPaola]

I have a customer build coming this week. The car is a 99 with a 420a. The build will include my own turbo manifold, charge pipes, head work, tuning, etc.

The budget is adequate, but I think we're coming up short due to the small market for 420A internals. The only viable option I see is the Eagle H beams, and the Je's.

What my question is, has there been any discovery in terms of an "intermediate" internal option. I'm looking at a possible race prep like I've done for road race engines where stock internals are required.

The deburr piston prep works well to suppress detonation but the cast piston in 420'a, from what I'm told, isn't highly reliable. I can improve rod strength about 25% through prep, but I think due to the lack of affordable, capable management, the internal strength of these motors hasn't been properly tested.

So are there any intermediate options?

Wiseco, Ross, and of course Venolia, also make pistons for this application. Besides Eagle, Crower makes rods -- they're expensive, but extremely strong. Personally, I would call Eagles/JE's a good "intermediate" option.

You'd be wrong about the 420A being untested. While the aftermarket hasn't given us too much though, we've compiled heaps of data from enthusiasts. Consensus is the stock bottom end is good for around 10psi of boost, before detonation becomes catastrophic. Some properly tuned bottom ends can withhold much more, but that's given lots of dyno time to eliminate knock.

If engine management is what you want, this is the upgrade path most follow:
Stock ECU/FMU (<8psi) >> Stock ECU/S-FMU (<15psi) >> Supp. fuel + spark control (Megasquirt, PortFueler/MSD, etc.)

Of course there are options like Tec3, Haltech, EMS, etc. but I wouldn't call those intermediate.

 

[rc000e]

Boost pressure is relative, and is not a cause for internal failure. 10psi out of a 14b and 10psi out of a GT40 are two different things. Peak torque and mechanical pressure on the rod and wrist pin is what is going to cause failure. You can't correlate psi to detonation because one doesn't have a direct relationship to the other.

When I speak in terms of intermediate options, I'm referring to OEM pistons with similar bore diameters and compression heights that can be used with an aftermarket or heavier OEM rod.

The budget for this build is adequate, and I mean that it's adequate to see the motor rebuilt and the entire setup built. It is coming up short though in terms of internals, which is why I'm exploring other options.

I will tune be tuning it for 10+psi on a mixture of management tools.

 

[VelocitàPaola]

The budget for this build is adequate, and I mean that it's adequate to see the motor rebuilt and the entire setup built. It is coming up short though in terms of internals, which is why I'm exploring other options.

I don't understand what you mean by this. If the budget is enough to include a proper rebuild, and plenty of piston/rod combinations exist, then what other options do you need?

I agree that pressure without flow rate is relatively useless, but those are the benchmarks used for a variety of reasons... I believe it started because FMU's can literally only handle so much boost pressure before they overrun the fuel pump and yield diminishing returns. The descriptions of the rest of the management techniques on the upgrade path follow suit.

I feel it's not fair to totally write off pressure in a correlation to detonation. If anything, it can not only contribute to knock, but certainly compound its effects. Once the intake valve is closed, flow rate is meaningless as basic stoichiometry and the Ideal Gas Law take precedence.

 

[totaleclipse_05]

The reason he is saying under 8 psi on Stock ECU+FMU is because at 8 psi the FMU is pumping over 120psi of fuel pressure (if you go with the 12:1, which most people do). SFMU at 15psi because anything over that and the ECU will begin to alter timing and you won't be able to do anything about that unless you have a standalone system or the AEM piggyback system.

 

[rc000e]

I don't understand what you mean by this. If the budget is enough to include a proper rebuild, and plenty of piston/rod combinations exist, then what other options do you need?

I apologize, it being "football day" and all, I was in a rush, and in yet another attempt to be clear I still wasn't. This is me trying to be close-lipped about budget just because that's not the forums business.

So, let me restate. The customer is on a set budget. Certain components were already chosen, leaving "x" amount of cash for the needed rebuild of this 420a. The issue is, with little flexibility in the budget, going the Eagle/JE route with the remaining funds is presenting an issue. So, therefore I was exploring other "intermediate" options.

In the Honda world, for example, we commonly use a Suzuki Vitara piston for our single cams as an "intermediate" piston option. It's not as strong as an aftermarket forged unit, but it's stronger than the stock cast piston. We've produced sohc 1.6's that have made in excess of 400whp on these pistons, which cost about 150.00 a set. Coupled with a SCAT rod, you have a high horsepower, very cheap build option.

I agree that pressure without flow rate is relatively useless, but those are the benchmarks used for a variety of reasons... I believe it started because FMU's can literally only handle so much boost pressure before they overrun the fuel pump and yield diminishing returns.

I agree, this is likely why I see alot more of this "talk" about psi in situations where enthusiasts have fewer options in terms of cheap management. It's clear you understand that point, but many MANY people do not.

So, since we both know that we both understand this, and I've not stated what compressor will be on this setup, then to appropriately answer my question, what are the hp/tq limitations of the stock internals, and have they or have they not been truly tested?

It's my feeling that due to the limited amount of enthusiasts in the 420a world that possibly this motor hasn't been tested in stock form, yet tuned with proper management. Is this a correct assumption, or no?

Consensus is the stock bottom end is good for around 10psi of boost, before detonation becomes catastrophic.

This statement led me to believe that you were implying a direct relationsip. Once again, you could have been citing psi more in terms of "noob" talk and it's relationship to the FMU approach. With an FMU approach and with the right corresponding conditions, I can see that a general 10psi statement and detonation can be made.


I've been "assigned" a turbo on this build, and I'm still trying to get specifics on the 420a so I can do some lb/min calculations. Does anyone know where I can locate some stock headflow cfm numbers, as well as peak ve% on these motors in stock form?

 

[tkelly27]

Will SRT-4 pistons and rods fit?

 

[VelocitàPaola]

Will SRT-4 pistons and rods fit?

No, but they will fit in the 2.4L 420A counterpart.

rc000e, thanks for clarifying: I'm glad we're on the same page now.

As far as I know, no stronger stock-type internals have been tested and confirmed. I can't recall HP/TQ numbers off the top of my head, but you might want to either PM or e-mail awddynamite. He was one of the first to really push the stock 420A to its limits. We know the pistons and rods are fairly capable -- pushing some as far as the low 11's in the 1/4 mile. Again, that's considering no detonation. The crank is still relatively untested since no one has yet to destroy it (bearing failure not withstanding). Your customer could probably benefit from headwork, but it wouldn't be necessary. Hahn pushed the stock head into the 10's.

 

[Locke]

at 8 psi the FMU is pumping over 120psi of fuel pressure (if you go with the 12:1, which most people do).

Nearing 150psi.

(You did say "over 120psi", so don't think I am correcting you. I'm not.

 

[link16]

One key thing to remember about this engine is: the ECU controls timing. Unless you go with a standalone you will be hardpressed to provide sufficient fuel with out knock or detonation. Hopefully this helps just a little when looking into your means of management.


(The 420A does not respond well to budgets either.)

 

[all_motor_mike]

u could use neon sohc pistons to lower compression but they are no stronger than stock 420a pistons.


AMM

 

[rc000e]

No, but they will fit in the 2.4L 420A counterpart.

rc000e, thanks for clarifying: I'm glad we're on the same page now.

As far as I know, no stronger stock-type internals have been tested and confirmed. I can't recall HP/TQ numbers off the top of my head, but you might want to either PM or e-mail awddynamite. He was one of the first to really push the stock 420A to its limits. We know the pistons and rods are fairly capable -- pushing some as far as the low 11's in the 1/4 mile. Again, that's considering no detonation. The crank is still relatively untested since no one has yet to destroy it (bearing failure not withstanding). Your customer could probably benefit from headwork, but it wouldn't be necessary. Hahn pushed the stock head into the 10's.

All good information there.

I'll be doing headwork to the extent that I'll be doing a basic streetport so as to maintain torque but remove turbulent areas and improve the intake/exhaust flow bias. I'll also work the chamber as a means of controlling stress risers.

The management will be a mixture of sorts at this point. Dyno numbers will do the talking though...I'm not getting into that now. I'll tell everyone the setup when I see what I can produce with it.


All Motor Mike...that's interest to know just in case. Whats the stock compression, and then the compression that results with the Neon pistons?

 

[VelocitàPaola]

Our stock compression ratio is 9.6:1, and I believe the compression ratio of a SOHC Neon is 9.0:1.

 

[rc000e]

I see...thank you.....

 

[BigRand]

I know this isn't exactly what you were looking for, but I figured, it might come in handy during your build anways.

http://www.2gnt.com/index.php?d=Specifications

The only "intermediate" option I can think of, is actually more or less not an option at all, but to only purchase after market pistions and leave the stock rods.

I have seen people on a budget try to cut cost in this department, however I am not sure of the results, but I think general consensus around the 420a community (IMO) is that the rods are a lot stronger then the pistions, however someone interested in doing a build usually just swaps both the pisitons and rods while there in there.

I think that you will find most of your power gains and opportunity for race prep on this type of motor, is going to be tuning, and I think your customer should really keep his mind on the engine management side of things as thats where people seem to come up short. It has been mentioned that megasquirt and porterfueler have been the two most user friendly and cost effective.

Last but not least, I do not know where you would find a forged typed pistion with the same compression ratio's as stock forum without having one custom made.

Good luck with the build, and we hope that you will return with an update from time to time.

 

[VelocitàPaola]

Last but not least, I do not know where you would find a forged typed pistion with the same compression ratio's as stock forum without having one custom made.

All Venolia pistons for this application are custom made anyway... you can specify any arbitrary compression ratio and they'll supply it.

 

[all_motor_mike]

Our stock compression ratio is 9.6:1, and I believe the compression ratio of a SOHC Neon is 9.0:1.

correct on the 9.6:1 paul but a sohc is actualy 9.8:1 (and i know nobody will care a but thats why a sohc auto will beat a dohc auto).......... but when u put the sohc piston with the bigger combo chamber of the dohc motor then u get a lower comp ratio of............. well i dont know off the top of my head to be honest........... but it works visa versa also when the sohc guys want a little more compression for cheap they throw some dohc pistons in and bump the comp ratio up to 10.3:1.


AMM

 

[VelocitàPaola]

correct on the 9.6:1 paul but a sohc is actualy 9.8:1.......... but when u put the sohc piston with the bigger combo chamber of the dohc motor then u get a lower comp ratio of............. well i dont know off the top of my head to be honest........... but it works visa versa also when the sohc guys want a little more compression for cheap they throw some dohc pistons in and bump the comp ratio up to 10.3:1.


AMM

I thought it was 9.0:1 once installed with a DOHC head...

 

[bullettdsm]

I thought it was 9.0:1 once installed with a DOHC head...

Hmm, not that it matters but, that's the number I have "heard" (i.e. researched) also.

MB

 

[all_motor_mike]

I thought it was 9.0:1 once installed with a DOHC head...

woops......... i thought u were talking about just a sohc engines compression not a dohc engine with sohc pistons.


AMM

 

[VelocitàPaola]

woops......... i thought u were talking about just a sohc engines compression not a dohc engine with sohc pistons.


AMM

My fault, I should have been clearer.

 

[totaleclipse_05]

Nearing 150psi.

(You did say "over 120psi", so don't think I am correcting you. I'm not.

Yeah, the 255lph high pressure pump is only good for around 120 psi, that's why I said that number.

 

[rc000e]

I'll definitely be here with updates during the build. I will be developing a full runner style manifold for this motor, and I will be developing full jigs to do reproduction. As soon as I can get this freakin noob thing lifted off of my head I've got intentions of becoming a sponsor of the site and really getting into doing products for the DSM world to break away from just Honda's.

I also have another build in house, but that's a 4G63 stroker with a 40R, and a stage 3 shep rebuild...ya'll don't wanna hear about that...

I appreciate everyones help here getting me filled in with some things I need to know. Let's see what this 420a is about.

Here's some of my other mani's just for reference, plus the mani in my avatar is mine as well....

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[link16]

Very nice.

When making your new manifold, try and allow for both of the cooling fans, and other various accesories.

I would like to see a manifold that puts the turbo on the driver's side of the car, allows for more room and possibly easier intercooler piping routes.

 

[rc000e]

Very interesting....

Does anyone share this view? Whatever I can make to help 420a guys out, as long as it sells and is cost effective for me, then I'll do it.

Can someone post a pic of a turbo'd 420a bay, so I can get a visual? The motor of my customers car is getting here Sat. so the build will begin, then once reinstalled, I have one turbo Civic to finish, then his car will be here. So I won't actually be hitting his turbo setup unit December sometime. Right now it's just parts purchasing and getting his motor rebuild and ready to go.

If anyone has any suggestions I'm wide open to hear them. (Honda-Tech doesn't have all these fun smileys to play with... )