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99gs777

Probationary Member
29
5
Mar 4, 2020
GORMANIA, West_Virginia
Had a 99 gs for a couple months now looking to build or possibly turbo. Not my first dsm had a 94 talon. Would like to gain info on what products everyone are using. Thanks everyone.
 
I know I'm gonna have rebuild my engine first off it producing blue smoke so probably valve seats or rings are done for so when in in that deep I want to do some rods and pistons and head studs to handle a turbo I know 420as aren't the best at handling boost on the stock internals
 
I know I'm gonna have rebuild my engine first off it producing blue smoke so probably valve seats or rings are done for so when in in that deep I want to do some rods and pistons and head studs to handle a turbo I know 420as aren't the best at handling boost on the stock internals
What is your peak hp goal?
 
What is your peak hp goal?
Well that is definitely possible. I forget what the stock hp is on a 420a, but a decent amount of people boost it. At the least I would do arp head studs and a cometic head gasket to handle the increase in cylinder pressure. I have a gst so I can't really help you, but I'm sure a little research will give you some good ideas. Just be smart about what you do. After you build the engine, try a fuel pump, injector, exhaust, and cold air intake. Those would be a good starting platform before you start boosting. A stock t25 off of a gst or gsx might work, or you might have to find a kit for it.
 
First, welcome!

Stock up is 150chp iirc. I did basic mods on my buddies back in the day and got 150whp out of it on the college Dyno after some small tweaks to cam timing on stock cams. Otherwise had intake, header, 2.5" full exh. and about 10.2:1 compression. It was kind of a turd which I attribute to the header and exhaust. Car was much more responsive with the stock system, so without cams to take advantage of the higher flow it was kinda worthless.

If built correctly a 420a can be quite impressive. Biggest limiting factors are lack of aftermarket support, no ready made tuning solutions that are cost effective and supported as well as mitsu powered cars, and some inherent drawbacks to certain systems in the 420a powered platform.

Fuel system is returnless so that changes tuning capabilities and mod paths. Can always swap to a return style system if budget allows.

ECM isn't programmable or flashable, so an aftermarket option like aem, megasquirt etc. Needs to be used when modifying to get any major benefit. Budget and knowledge permitting here.

Certain weak points if the 420a engine itself, like the head bolts, should be swapped out. One of the firewall side bolts is different that the others (shorter/shallower?) than the rest and can cause issues in stock trim, let alone aftermarket.
Personally I've also had poor luck with cam and cranks sensors on the engines, they seem to fail regularly with general aftermarket replacements that are available.

There's more that I'm forgetting or just not as knowledgeable in, but I'm sure some n/t guys will chime in.

As with any upgrade path, set a goal, research, research some more, and then research even more before diving in.
Personally I'd love to see a supercharger 420a again, always thought that was done pretty nicely back in the day.

Once again, welcome and GL!
 
I think it's about 120 or 110hp
Well that is definitely possible. I forget what the stock hp is on a 420a, but a decent amount of people boost it. At the least I would do arp head studs and a cometic head gasket to handle the increase in cylinder pressure. I have a gst so I can't really help you, but I'm sure a little research will give you some good ideas. Just be smart about what you do. After you build the engine, try a fuel pump, injector, exhaust, and cold air intake. Those would be a good starting platform before you start boosting. A stock t25 off of a gst or gsx might work, or you might have to find a kit for it.

Thanks for ur reply yeah I have to see I have a few things done but I definitely need a fuel pump and injectors before I go turbo
 
First, welcome!

Stock up is 150chp iirc. I did basic mods on my buddies back in the day and got 150whp out of it on the college Dyno after some small tweaks to cam timing on stock cams. Otherwise had intake, header, 2.5" full exh. and about 10.2:1 compression. It was kind of a turd which I attribute to the header and exhaust. Car was much more responsive with the stock system, so without cams to take advantage of the higher flow it was kinda worthless.

If built correctly a 420a can be quite impressive. Biggest limiting factors are lack of aftermarket support, no ready made tuning solutions that are cost effective and supported as well as mitsu powered cars, and some inherent drawbacks to certain systems in the 420a powered platform.

Fuel system is returnless so that changes tuning capabilities and mod paths. Can always swap to a return style system if budget allows.

ECM isn't programmable or flashable, so an aftermarket option like aem, megasquirt etc. Needs to be used when modifying to get any major benefit. Budget and knowledge permitting here.

Certain weak points if the 420a engine itself, like the head bolts, should be swapped out. One of the firewall side bolts is different that the others (shorter/shallower?) than the rest and can cause issues in stock trim, let alone aftermarket.
Personally I've also had poor luck with cam and cranks sensors on the engines, they seem to fail regularly with general aftermarket replacements that are available.

There's more that I'm forgetting or just not as knowledgeable in, but I'm sure some n/t guys will chime in.

As with any upgrade path, set a goal, research, research some more, and then research even more before diving in.
Personally I'd love to see a supercharger 420a again, always thought that was done pretty nicely back in the day.

Once again, welcome and GL!

Thanks for the welcomes ... yeah I have done some research and they have some problems with the one stud being longer causing issues and the sensors leaking as well I have a few things done like headers test tube cat back and a cai really thinking hard about turboing it to make at least 250 hp or 220hp just want to have alil fun
 
I think it's about 120 or 110hp


Thanks for ur reply yeah I have to see I have a few things done but I definitely need a fuel pump and injectors before I go turbo
Yeah I would do the headstuds, headgasket, injectors, and fuel pump. Do all of those then get a tune and see how much hp you are making. Once you know it is reliable and won't grenade itself when boosting it, then ad a spooly boi :)
 
you could evo swap it.......
Yeah I would do the headstuds, headgasket, injectors, and fuel pump. Do all of those then get a tune and see how much hp you are making. Once you know it is reliable and won't grenade itself when boosting it, then ad a spooly boi :)

10 4 I like the way u think been itching to get something turbo or turboing something LOL
 
Nice I know alot of guy around here that has hondas running decent power one guy is running like 32lb of boost on a stock crank I was surprised LOL
 
Welcome! I haven't personally built any 420a's. But your power goal is doable, I had a local buddy make almost 500whp on a 420. Till he went to evo's now though.
 
Thanks for the welcome...I thought I would go reasonable with the goal till I get a better understanding on what parts works with what then when I get a chance later down the road get a 4g63t and make a monster
 
As much as some of us hate hondas (I love them personally) they are tough little critters
Yeah for sure 300k on a stock engine is common aftermarket support is huge and common hard parts are surprisingly inexpensive.. I can appreciate any car that someone puts work into.
 
Yeah for sure 300k on a stock engine is common aftermarket support is huge and common hard parts are surprisingly inexpensive.. I can appreciate any car that someone puts work into.
I have a very limited budget.....if I was smart I would have bought a civic...not a dsm where everything is 3 times the price of civic parts.....
 
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