{"product_id":"exhaust-header-for-jeep-wrangler-grand-cherokee-1991-1999-4-0l","title":"Exhaust Header for Jeep Wrangler Grand Cherokee (1991-1999) 4.0L","description":"\u003ch2\u003eHeavy-Duty Stainless Steel Exhaust Header for 1991-1999 Jeep Wrangler,Grand Cherokee\u003c\/h2\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e The performance exhaust header replaces the crack-prone factory manifold on 1991-1999 Jeep Wrangler and Grand Cherokee models to eliminate exhaust leaks, lower backpressure, and improve low-end torque delivery.\u003c\/p\u003e\n\n\u003ch3\u003eThe Stock Jeep Wrangler,Grand Cherokee Exhaust Manifold Failure\u003c\/h3\u003e\n\u003cp\u003eFactory exhaust manifolds on the \u003cstrong\u003eAMC 242\u003c\/strong\u003e inline-six engine are plagued by a notorious design flaw: stress cracking at the runner collector junctions. Because the cast iron cylinder head on the \u003cstrong\u003eYJ\u003c\/strong\u003e, \u003cstrong\u003eTJ\u003c\/strong\u003e, and \u003cstrong\u003eZJ\u003c\/strong\u003e platforms spans a long inline architecture, uneven thermal expansion subjects the OEM thin-gauge manifold to extreme shear forces. Combined with powertrain movement under load, the stock runners fatigue, crack, and leak. This structural failure causes loud exhaust ticks, upstream O2 sensor false-lean readings, compromised fuel trim management, and a noticeable loss of low-rpm crawling power.\u003c\/p\u003e\n\n\u003ch3\u003eThe Engineering Solution\u003c\/h3\u003e\n\u003cp\u003eEngineered to resolve thermal stress fatigue, this direct replacement header is constructed from high-grade stainless steel with smooth, mandrel-bent primary tubes. The continuous radius bends reduce exhaust flow turbulence, improving cylinder scavenging during the valve overlap cycle. Heavy-duty, precision-machined mounting flanges resist heat warping to provide a flat, persistent seal against the engine block. Reinforced collector joints withstand aggressive engine-mount torque articulation without shearing, safeguarding exhaust gas velocity and restoring crisp throttle response on and off the trail.\u003c\/p\u003e\n\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003ctable width=\"100%\" style=\"border-collapse: collapse; border: 1px solid #e0e0e0; font-size: 14px; margin-bottom: 20px;\"\u003e\n  \u003ctr style=\"background-color: #f9f9f9;\"\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eFitment\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e1991-1999 Jeep Wrangler, Grand Cherokee\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eEngine \/ Chassis\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e\n\u003cstrong\u003eAMC 242\u003c\/strong\u003e 4.0L I6 \/ \u003cstrong\u003eYJ\u003c\/strong\u003e, \u003cstrong\u003eTJ\u003c\/strong\u003e, \u003cstrong\u003eZJ\u003c\/strong\u003e, \u003cstrong\u003eWJ\u003c\/strong\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr style=\"background-color: #f9f9f9;\"\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eStock Output\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e190 hp \/ 225 lb-ft\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eReplaces OEM Part #\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003eSP-EH0006\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eCompatibility\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e1991-1995 Jeep Wrangler (YJ) 4.0L Inline-6\u003c\/li\u003e\n  \u003cli\u003e1997-1999 Jeep Wrangler (TJ) 4.0L Inline-6\u003c\/li\u003e\n  \u003cli\u003e1993-1998 Jeep Grand Cherokee (ZJ) 4.0L Inline-6\u003c\/li\u003e\n  \u003cli\u003e1999 Jeep Grand Cherokee (WJ) 4.0L Inline-6\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eDoes this fit the TJ Wrangler,Grand Cherokee?\u003c\/strong\u003e\u003cbr\u003e Yes, this is a direct fit for the 1991-1999 Jeep Wrangler and Grand Cherokee equipped with the \u003cstrong\u003eAMC 242\u003c\/strong\u003e 4.0L engine.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWill installation require custom welding or ECM tuning?\u003c\/strong\u003e\u003cbr\u003e No, this assembly bolts directly to the factory downpipe location and operates cleanly within factory ECU closed-loop fuel parameters without tuning.\u003c\/p\u003e\n\n\u003ch3\u003eThe Jeep Durability Standard\u003c\/h3\u003e\n\u003cp\u003eBuilt to handle harsh off-camber trail flex and severe high-heat rock crawling, this header assembly withstands brutal operating environments where brittle stock castings consistently split apart.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":50607114387704,"sku":"DS-E3FKLWX8F","price":210.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0800\/1290\/2648\/files\/exhaust-header-for-jeep-wrangler-grand-cherokee-1991-1999-4-0l-1.jpg?v=1790090975","url":"https:\/\/performancechiptuning.com\/fr\/products\/exhaust-header-for-jeep-wrangler-grand-cherokee-1991-1999-4-0l","provider":"Performance Chip Tuning","version":"1.0","type":"link"}